]> git.vpit.fr Git - perl/modules/re-engine-Hooks.git/blobdiff - src/5017006/orig/regexec.c
Add support for perl 5.12.5 and 5.17.[678]
[perl/modules/re-engine-Hooks.git] / src / 5017006 / orig / regexec.c
diff --git a/src/5017006/orig/regexec.c b/src/5017006/orig/regexec.c
new file mode 100644 (file)
index 0000000..d0560ce
--- /dev/null
@@ -0,0 +1,7772 @@
+/*    regexec.c
+ */
+
+/*
+ *     One Ring to rule them all, One Ring to find them
+ &
+ *     [p.v of _The Lord of the Rings_, opening poem]
+ *     [p.50 of _The Lord of the Rings_, I/iii: "The Shadow of the Past"]
+ *     [p.254 of _The Lord of the Rings_, II/ii: "The Council of Elrond"]
+ */
+
+/* This file contains functions for executing a regular expression.  See
+ * also regcomp.c which funnily enough, contains functions for compiling
+ * a regular expression.
+ *
+ * This file is also copied at build time to ext/re/re_exec.c, where
+ * it's built with -DPERL_EXT_RE_BUILD -DPERL_EXT_RE_DEBUG -DPERL_EXT.
+ * This causes the main functions to be compiled under new names and with
+ * debugging support added, which makes "use re 'debug'" work.
+ */
+
+/* NOTE: this is derived from Henry Spencer's regexp code, and should not
+ * confused with the original package (see point 3 below).  Thanks, Henry!
+ */
+
+/* Additional note: this code is very heavily munged from Henry's version
+ * in places.  In some spots I've traded clarity for efficiency, so don't
+ * blame Henry for some of the lack of readability.
+ */
+
+/* The names of the functions have been changed from regcomp and
+ * regexec to  pregcomp and pregexec in order to avoid conflicts
+ * with the POSIX routines of the same names.
+*/
+
+#ifdef PERL_EXT_RE_BUILD
+#include "re_top.h"
+#endif
+
+/* At least one required character in the target string is expressible only in
+ * UTF-8. */
+static const char* const non_utf8_target_but_utf8_required
+                = "Can't match, because target string needs to be in UTF-8\n";
+
+#define NON_UTF8_TARGET_BUT_UTF8_REQUIRED(target) STMT_START { \
+    DEBUG_EXECUTE_r(PerlIO_printf(Perl_debug_log, "%s", non_utf8_target_but_utf8_required));\
+    goto target; \
+} STMT_END
+
+/*
+ * pregcomp and pregexec -- regsub and regerror are not used in perl
+ *
+ *     Copyright (c) 1986 by University of Toronto.
+ *     Written by Henry Spencer.  Not derived from licensed software.
+ *
+ *     Permission is granted to anyone to use this software for any
+ *     purpose on any computer system, and to redistribute it freely,
+ *     subject to the following restrictions:
+ *
+ *     1. The author is not responsible for the consequences of use of
+ *             this software, no matter how awful, even if they arise
+ *             from defects in it.
+ *
+ *     2. The origin of this software must not be misrepresented, either
+ *             by explicit claim or by omission.
+ *
+ *     3. Altered versions must be plainly marked as such, and must not
+ *             be misrepresented as being the original software.
+ *
+ ****    Alterations to Henry's code are...
+ ****
+ ****    Copyright (C) 1991, 1992, 1993, 1994, 1995, 1996, 1997, 1998, 1999,
+ ****    2000, 2001, 2002, 2003, 2004, 2005, 2006, 2007, 2008
+ ****    by Larry Wall and others
+ ****
+ ****    You may distribute under the terms of either the GNU General Public
+ ****    License or the Artistic License, as specified in the README file.
+ *
+ * Beware that some of this code is subtly aware of the way operator
+ * precedence is structured in regular expressions.  Serious changes in
+ * regular-expression syntax might require a total rethink.
+ */
+#include "EXTERN.h"
+#define PERL_IN_REGEXEC_C
+#include "perl.h"
+
+#ifdef PERL_IN_XSUB_RE
+#  include "re_comp.h"
+#else
+#  include "regcomp.h"
+#endif
+
+#include "inline_invlist.c"
+#include "unicode_constants.h"
+
+#define RF_tainted     1       /* tainted information used? e.g. locale */
+#define RF_warned      2               /* warned about big count? */
+
+#define RF_utf8                8               /* Pattern contains multibyte chars? */
+
+#define UTF_PATTERN ((PL_reg_flags & RF_utf8) != 0)
+
+#define HAS_NONLATIN1_FOLD_CLOSURE(i) _HAS_NONLATIN1_FOLD_CLOSURE_ONLY_FOR_USE_BY_REGCOMP_DOT_C_AND_REGEXEC_DOT_C(i)
+
+#ifndef STATIC
+#define        STATIC  static
+#endif
+
+/* Valid for non-utf8 strings: avoids the reginclass
+ * call if there are no complications: i.e., if everything matchable is
+ * straight forward in the bitmap */
+#define REGINCLASS(prog,p,c)  (ANYOF_FLAGS(p) ? reginclass(prog,p,c,0)   \
+                                             : ANYOF_BITMAP_TEST(p,*(c)))
+
+/*
+ * Forwards.
+ */
+
+#define CHR_SVLEN(sv) (utf8_target ? sv_len_utf8(sv) : SvCUR(sv))
+#define CHR_DIST(a,b) (PL_reg_match_utf8 ? utf8_distance(a,b) : a - b)
+
+#define HOPc(pos,off) \
+       (char *)(PL_reg_match_utf8 \
+           ? reghop3((U8*)pos, off, (U8*)(off >= 0 ? PL_regeol : PL_bostr)) \
+           : (U8*)(pos + off))
+#define HOPBACKc(pos, off) \
+       (char*)(PL_reg_match_utf8\
+           ? reghopmaybe3((U8*)pos, -off, (U8*)PL_bostr) \
+           : (pos - off >= PL_bostr)           \
+               ? (U8*)pos - off                \
+               : NULL)
+
+#define HOP3(pos,off,lim) (PL_reg_match_utf8 ? reghop3((U8*)(pos), off, (U8*)(lim)) : (U8*)(pos + off))
+#define HOP3c(pos,off,lim) ((char*)HOP3(pos,off,lim))
+
+
+#define NEXTCHR_EOS -10 /* nextchr has fallen off the end */
+#define NEXTCHR_IS_EOS (nextchr < 0)
+
+#define SET_nextchr \
+    nextchr = ((locinput < PL_regeol) ? UCHARAT(locinput) : NEXTCHR_EOS)
+
+#define SET_locinput(p) \
+    locinput = (p);  \
+    SET_nextchr
+
+
+/* these are unrolled below in the CCC_TRY_XXX defined */
+#define LOAD_UTF8_CHARCLASS(class,str) STMT_START { \
+    if (!CAT2(PL_utf8_,class)) { \
+       bool ok; \
+       ENTER; save_re_context(); \
+       ok=CAT2(is_utf8_,class)((const U8*)str); \
+        PERL_UNUSED_VAR(ok); \
+       assert(ok); assert(CAT2(PL_utf8_,class)); LEAVE; } } STMT_END
+/* Doesn't do an assert to verify that is correct */
+#define LOAD_UTF8_CHARCLASS_NO_CHECK(class) STMT_START { \
+    if (!CAT2(PL_utf8_,class)) { \
+       bool throw_away PERL_UNUSED_DECL; \
+       ENTER; save_re_context(); \
+       throw_away = CAT2(is_utf8_,class)((const U8*)" "); \
+        PERL_UNUSED_VAR(throw_away); \
+       LEAVE; } } STMT_END
+
+#define LOAD_UTF8_CHARCLASS_ALNUM() LOAD_UTF8_CHARCLASS(alnum,"a")
+#define LOAD_UTF8_CHARCLASS_DIGIT() LOAD_UTF8_CHARCLASS(digit,"0")
+
+#define LOAD_UTF8_CHARCLASS_GCB()  /* Grapheme cluster boundaries */        \
+        /* No asserts are done for some of these, in case called on a   */  \
+        /* Unicode version in which they map to nothing */                  \
+       LOAD_UTF8_CHARCLASS(X_regular_begin, HYPHEN_UTF8);                          \
+       LOAD_UTF8_CHARCLASS(X_extend, COMBINING_GRAVE_ACCENT_UTF8);         \
+
+#define PLACEHOLDER    /* Something for the preprocessor to grab onto */
+
+/* The actual code for CCC_TRY, which uses several variables from the routine
+ * it's callable from.  It is designed to be the bulk of a case statement.
+ * FUNC is the macro or function to call on non-utf8 targets that indicate if
+ *      nextchr matches the class.
+ * UTF8_TEST is the whole test string to use for utf8 targets
+ * LOAD is what to use to test, and if not present to load in the swash for the
+ *     class
+ * POS_OR_NEG is either empty or ! to complement the results of FUNC or
+ *     UTF8_TEST test.
+ * The logic is: Fail if we're at the end-of-string; otherwise if the target is
+ * utf8 and a variant, load the swash if necessary and test using the utf8
+ * test.  Advance to the next character if test is ok, otherwise fail; If not
+ * utf8 or an invariant under utf8, use the non-utf8 test, and fail if it
+ * fails, or advance to the next character */
+
+#define _CCC_TRY_CODE(POS_OR_NEG, FUNC, UTF8_TEST, CLASS, STR)                \
+    if (NEXTCHR_IS_EOS) {                                              \
+       sayNO;                                                                \
+    }                                                                         \
+    if (utf8_target && UTF8_IS_CONTINUED(nextchr)) {                          \
+       LOAD_UTF8_CHARCLASS(CLASS, STR);                                      \
+       if (POS_OR_NEG (UTF8_TEST)) {                                         \
+           sayNO;                                                            \
+       }                                                                     \
+    }                                                                         \
+    else if (POS_OR_NEG (FUNC(nextchr))) {                                    \
+            sayNO;                                                            \
+    }                                                                         \
+    goto increment_locinput;
+
+/* Handle the non-locale cases for a character class and its complement.  It
+ * calls _CCC_TRY_CODE with a ! to complement the test for the character class.
+ * This is because that code fails when the test succeeds, so we want to have
+ * the test fail so that the code succeeds.  The swash is stored in a
+ * predictable PL_ place */
+#define _CCC_TRY_NONLOCALE(NAME,  NNAME,  FUNC,                               \
+                          CLASS, STR)                                        \
+    case NAME:                                                                \
+       _CCC_TRY_CODE( !, FUNC,                                               \
+                         cBOOL(swash_fetch(CAT2(PL_utf8_,CLASS),             \
+                                           (U8*)locinput, TRUE)),            \
+                         CLASS, STR)                                         \
+    case NNAME:                                                               \
+       _CCC_TRY_CODE(  PLACEHOLDER , FUNC,                                   \
+                         cBOOL(swash_fetch(CAT2(PL_utf8_,CLASS),             \
+                                           (U8*)locinput, TRUE)),            \
+                         CLASS, STR)                                         \
+
+/* Generate the case statements for both locale and non-locale character
+ * classes in regmatch for classes that don't have special unicode semantics.
+ * Locales don't use an immediate swash, but an intermediary special locale
+ * function that is called on the pointer to the current place in the input
+ * string.  That function will resolve to needing the same swash.  One might
+ * think that because we don't know what the locale will match, we shouldn't
+ * check with the swash loading function that it loaded properly; ie, that we
+ * should use LOAD_UTF8_CHARCLASS_NO_CHECK for those, but what is passed to the
+ * regular LOAD_UTF8_CHARCLASS is in non-locale terms, and so locale is
+ * irrelevant here */
+#define CCC_TRY(NAME,  NNAME,  FUNC,                                          \
+               NAMEL, NNAMEL, LCFUNC, LCFUNC_utf8,                           \
+               NAMEA, NNAMEA, FUNCA,                                         \
+               CLASS, STR)                                                   \
+    case NAMEL:                                                               \
+       PL_reg_flags |= RF_tainted;                                           \
+       _CCC_TRY_CODE( !, LCFUNC, LCFUNC_utf8((U8*)locinput), CLASS, STR)     \
+    case NNAMEL:                                                              \
+       PL_reg_flags |= RF_tainted;                                           \
+       _CCC_TRY_CODE( PLACEHOLDER, LCFUNC, LCFUNC_utf8((U8*)locinput),       \
+                      CLASS, STR)                                            \
+    case NAMEA:                                                               \
+       if (NEXTCHR_IS_EOS || ! FUNCA(nextchr)) {                      \
+           sayNO;                                                            \
+       }                                                                     \
+       /* Matched a utf8-invariant, so don't have to worry about utf8 */     \
+       locinput++;                                        \
+       break;                                                                \
+    case NNAMEA:                                                              \
+       if (NEXTCHR_IS_EOS || FUNCA(nextchr)) {                        \
+           sayNO;                                                            \
+       }                                                                     \
+        goto increment_locinput;                                              \
+    /* Generate the non-locale cases */                                       \
+    _CCC_TRY_NONLOCALE(NAME, NNAME, FUNC, CLASS, STR)
+
+/* This is like CCC_TRY, but has an extra set of parameters for generating case
+ * statements to handle separate Unicode semantics nodes */
+#define CCC_TRY_U(NAME,  NNAME,  FUNC,                                         \
+                 NAMEL, NNAMEL, LCFUNC, LCFUNC_utf8,                          \
+                 NAMEU, NNAMEU, FUNCU,                                        \
+                 NAMEA, NNAMEA, FUNCA,                                        \
+                 CLASS, STR)                                                  \
+    CCC_TRY(NAME, NNAME, FUNC,                                                 \
+           NAMEL, NNAMEL, LCFUNC, LCFUNC_utf8,                                \
+           NAMEA, NNAMEA, FUNCA,                                              \
+           CLASS, STR)                                                        \
+    _CCC_TRY_NONLOCALE(NAMEU, NNAMEU, FUNCU, CLASS, STR)
+
+/* TODO: Combine JUMPABLE and HAS_TEXT to cache OP(rn) */
+
+/* for use after a quantifier and before an EXACT-like node -- japhy */
+/* it would be nice to rework regcomp.sym to generate this stuff. sigh
+ *
+ * NOTE that *nothing* that affects backtracking should be in here, specifically
+ * VERBS must NOT be included. JUMPABLE is used to determine  if we can ignore a
+ * node that is in between two EXACT like nodes when ascertaining what the required
+ * "follow" character is. This should probably be moved to regex compile time
+ * although it may be done at run time beause of the REF possibility - more
+ * investigation required. -- demerphq
+*/
+#define JUMPABLE(rn) (      \
+    OP(rn) == OPEN ||       \
+    (OP(rn) == CLOSE && (!cur_eval || cur_eval->u.eval.close_paren != ARG(rn))) || \
+    OP(rn) == EVAL ||   \
+    OP(rn) == SUSPEND || OP(rn) == IFMATCH || \
+    OP(rn) == PLUS || OP(rn) == MINMOD || \
+    OP(rn) == KEEPS || \
+    (PL_regkind[OP(rn)] == CURLY && ARG1(rn) > 0) \
+)
+#define IS_EXACT(rn) (PL_regkind[OP(rn)] == EXACT)
+
+#define HAS_TEXT(rn) ( IS_EXACT(rn) || PL_regkind[OP(rn)] == REF )
+
+#if 0 
+/* Currently these are only used when PL_regkind[OP(rn)] == EXACT so
+   we don't need this definition. */
+#define IS_TEXT(rn)   ( OP(rn)==EXACT   || OP(rn)==REF   || OP(rn)==NREF   )
+#define IS_TEXTF(rn)  ( OP(rn)==EXACTFU || OP(rn)==EXACTFU_SS || OP(rn)==EXACTFU_TRICKYFOLD || OP(rn)==EXACTFA || OP(rn)==EXACTF || OP(rn)==REFF  || OP(rn)==NREFF )
+#define IS_TEXTFL(rn) ( OP(rn)==EXACTFL || OP(rn)==REFFL || OP(rn)==NREFFL )
+
+#else
+/* ... so we use this as its faster. */
+#define IS_TEXT(rn)   ( OP(rn)==EXACT   )
+#define IS_TEXTFU(rn)  ( OP(rn)==EXACTFU || OP(rn)==EXACTFU_SS || OP(rn)==EXACTFU_TRICKYFOLD || OP(rn) == EXACTFA)
+#define IS_TEXTF(rn)  ( OP(rn)==EXACTF  )
+#define IS_TEXTFL(rn) ( OP(rn)==EXACTFL )
+
+#endif
+
+/*
+  Search for mandatory following text node; for lookahead, the text must
+  follow but for lookbehind (rn->flags != 0) we skip to the next step.
+*/
+#define FIND_NEXT_IMPT(rn) STMT_START { \
+    while (JUMPABLE(rn)) { \
+       const OPCODE type = OP(rn); \
+       if (type == SUSPEND || PL_regkind[type] == CURLY) \
+           rn = NEXTOPER(NEXTOPER(rn)); \
+       else if (type == PLUS) \
+           rn = NEXTOPER(rn); \
+       else if (type == IFMATCH) \
+           rn = (rn->flags == 0) ? NEXTOPER(NEXTOPER(rn)) : rn + ARG(rn); \
+       else rn += NEXT_OFF(rn); \
+    } \
+} STMT_END 
+
+
+static void restore_pos(pTHX_ void *arg);
+
+#define REGCP_PAREN_ELEMS 3
+#define REGCP_OTHER_ELEMS 3
+#define REGCP_FRAME_ELEMS 1
+/* REGCP_FRAME_ELEMS are not part of the REGCP_OTHER_ELEMS and
+ * are needed for the regexp context stack bookkeeping. */
+
+STATIC CHECKPOINT
+S_regcppush(pTHX_ const regexp *rex, I32 parenfloor)
+{
+    dVAR;
+    const int retval = PL_savestack_ix;
+    const int paren_elems_to_push = (PL_regsize - parenfloor) * REGCP_PAREN_ELEMS;
+    const UV total_elems = paren_elems_to_push + REGCP_OTHER_ELEMS;
+    const UV elems_shifted = total_elems << SAVE_TIGHT_SHIFT;
+    I32 p;
+    GET_RE_DEBUG_FLAGS_DECL;
+
+    PERL_ARGS_ASSERT_REGCPPUSH;
+
+    if (paren_elems_to_push < 0)
+       Perl_croak(aTHX_ "panic: paren_elems_to_push, %i < 0",
+                  paren_elems_to_push);
+
+    if ((elems_shifted >> SAVE_TIGHT_SHIFT) != total_elems)
+       Perl_croak(aTHX_ "panic: paren_elems_to_push offset %"UVuf
+                  " out of range (%lu-%ld)",
+                  total_elems, (unsigned long)PL_regsize, (long)parenfloor);
+
+    SSGROW(total_elems + REGCP_FRAME_ELEMS);
+    
+    DEBUG_BUFFERS_r(
+       if ((int)PL_regsize > (int)parenfloor)
+           PerlIO_printf(Perl_debug_log,
+               "rex=0x%"UVxf" offs=0x%"UVxf": saving capture indices:\n",
+               PTR2UV(rex),
+               PTR2UV(rex->offs)
+           );
+    );
+    for (p = parenfloor+1; p <= (I32)PL_regsize;  p++) {
+/* REGCP_PARENS_ELEMS are pushed per pairs of parentheses. */
+       SSPUSHINT(rex->offs[p].end);
+       SSPUSHINT(rex->offs[p].start);
+       SSPUSHINT(rex->offs[p].start_tmp);
+       DEBUG_BUFFERS_r(PerlIO_printf(Perl_debug_log,
+           "    \\%"UVuf": %"IVdf"(%"IVdf")..%"IVdf"\n",
+           (UV)p,
+           (IV)rex->offs[p].start,
+           (IV)rex->offs[p].start_tmp,
+           (IV)rex->offs[p].end
+       ));
+    }
+/* REGCP_OTHER_ELEMS are pushed in any case, parentheses or no. */
+    SSPUSHINT(PL_regsize);
+    SSPUSHINT(rex->lastparen);
+    SSPUSHINT(rex->lastcloseparen);
+    SSPUSHUV(SAVEt_REGCONTEXT | elems_shifted); /* Magic cookie. */
+
+    return retval;
+}
+
+/* These are needed since we do not localize EVAL nodes: */
+#define REGCP_SET(cp)                                           \
+    DEBUG_STATE_r(                                              \
+            PerlIO_printf(Perl_debug_log,                      \
+               "  Setting an EVAL scope, savestack=%"IVdf"\n", \
+               (IV)PL_savestack_ix));                          \
+    cp = PL_savestack_ix
+
+#define REGCP_UNWIND(cp)                                        \
+    DEBUG_STATE_r(                                              \
+        if (cp != PL_savestack_ix)                             \
+           PerlIO_printf(Perl_debug_log,                       \
+               "  Clearing an EVAL scope, savestack=%"IVdf"..%"IVdf"\n", \
+               (IV)(cp), (IV)PL_savestack_ix));                \
+    regcpblow(cp)
+
+#define UNWIND_PAREN(lp, lcp)               \
+    for (n = rex->lastparen; n > lp; n--)   \
+        rex->offs[n].end = -1;              \
+    rex->lastparen = n;                     \
+    rex->lastcloseparen = lcp;
+
+
+STATIC void
+S_regcppop(pTHX_ regexp *rex)
+{
+    dVAR;
+    UV i;
+    U32 paren;
+    GET_RE_DEBUG_FLAGS_DECL;
+
+    PERL_ARGS_ASSERT_REGCPPOP;
+
+    /* Pop REGCP_OTHER_ELEMS before the parentheses loop starts. */
+    i = SSPOPUV;
+    assert((i & SAVE_MASK) == SAVEt_REGCONTEXT); /* Check that the magic cookie is there. */
+    i >>= SAVE_TIGHT_SHIFT; /* Parentheses elements to pop. */
+    rex->lastcloseparen = SSPOPINT;
+    rex->lastparen = SSPOPINT;
+    PL_regsize = SSPOPINT;
+
+    i -= REGCP_OTHER_ELEMS;
+    /* Now restore the parentheses context. */
+    DEBUG_BUFFERS_r(
+       if (i || rex->lastparen + 1 <= rex->nparens)
+           PerlIO_printf(Perl_debug_log,
+               "rex=0x%"UVxf" offs=0x%"UVxf": restoring capture indices to:\n",
+               PTR2UV(rex),
+               PTR2UV(rex->offs)
+           );
+    );
+    paren = PL_regsize;
+    for ( ; i > 0; i -= REGCP_PAREN_ELEMS) {
+       I32 tmps;
+       rex->offs[paren].start_tmp = SSPOPINT;
+       rex->offs[paren].start = SSPOPINT;
+       tmps = SSPOPINT;
+       if (paren <= rex->lastparen)
+           rex->offs[paren].end = tmps;
+       DEBUG_BUFFERS_r( PerlIO_printf(Perl_debug_log,
+           "    \\%"UVuf": %"IVdf"(%"IVdf")..%"IVdf"%s\n",
+           (UV)paren,
+           (IV)rex->offs[paren].start,
+           (IV)rex->offs[paren].start_tmp,
+           (IV)rex->offs[paren].end,
+           (paren > rex->lastparen ? "(skipped)" : ""));
+       );
+       paren--;
+    }
+#if 1
+    /* It would seem that the similar code in regtry()
+     * already takes care of this, and in fact it is in
+     * a better location to since this code can #if 0-ed out
+     * but the code in regtry() is needed or otherwise tests
+     * requiring null fields (pat.t#187 and split.t#{13,14}
+     * (as of patchlevel 7877)  will fail.  Then again,
+     * this code seems to be necessary or otherwise
+     * this erroneously leaves $1 defined: "1" =~ /^(?:(\d)x)?\d$/
+     * --jhi updated by dapm */
+    for (i = rex->lastparen + 1; i <= rex->nparens; i++) {
+       if (i > PL_regsize)
+           rex->offs[i].start = -1;
+       rex->offs[i].end = -1;
+       DEBUG_BUFFERS_r( PerlIO_printf(Perl_debug_log,
+           "    \\%"UVuf": %s   ..-1 undeffing\n",
+           (UV)i,
+           (i > PL_regsize) ? "-1" : "  "
+       ));
+    }
+#endif
+}
+
+/* restore the parens and associated vars at savestack position ix,
+ * but without popping the stack */
+
+STATIC void
+S_regcp_restore(pTHX_ regexp *rex, I32 ix)
+{
+    I32 tmpix = PL_savestack_ix;
+    PL_savestack_ix = ix;
+    regcppop(rex);
+    PL_savestack_ix = tmpix;
+}
+
+#define regcpblow(cp) LEAVE_SCOPE(cp)  /* Ignores regcppush()ed data. */
+
+/*
+ * pregexec and friends
+ */
+
+#ifndef PERL_IN_XSUB_RE
+/*
+ - pregexec - match a regexp against a string
+ */
+I32
+Perl_pregexec(pTHX_ REGEXP * const prog, char* stringarg, register char *strend,
+        char *strbeg, I32 minend, SV *screamer, U32 nosave)
+/* stringarg: the point in the string at which to begin matching */
+/* strend:    pointer to null at end of string */
+/* strbeg:    real beginning of string */
+/* minend:    end of match must be >= minend bytes after stringarg. */
+/* screamer:  SV being matched: only used for utf8 flag, pos() etc; string
+ *            itself is accessed via the pointers above */
+/* nosave:    For optimizations. */
+{
+    PERL_ARGS_ASSERT_PREGEXEC;
+
+    return
+       regexec_flags(prog, stringarg, strend, strbeg, minend, screamer, NULL,
+                     nosave ? 0 : REXEC_COPY_STR);
+}
+#endif
+
+/*
+ * Need to implement the following flags for reg_anch:
+ *
+ * USE_INTUIT_NOML             - Useful to call re_intuit_start() first
+ * USE_INTUIT_ML
+ * INTUIT_AUTORITATIVE_NOML    - Can trust a positive answer
+ * INTUIT_AUTORITATIVE_ML
+ * INTUIT_ONCE_NOML            - Intuit can match in one location only.
+ * INTUIT_ONCE_ML
+ *
+ * Another flag for this function: SECOND_TIME (so that float substrs
+ * with giant delta may be not rechecked).
+ */
+
+/* Assumptions: if ANCH_GPOS, then strpos is anchored. XXXX Check GPOS logic */
+
+/* If SCREAM, then SvPVX_const(sv) should be compatible with strpos and strend.
+   Otherwise, only SvCUR(sv) is used to get strbeg. */
+
+/* XXXX We assume that strpos is strbeg unless sv. */
+
+/* XXXX Some places assume that there is a fixed substring.
+       An update may be needed if optimizer marks as "INTUITable"
+       RExen without fixed substrings.  Similarly, it is assumed that
+       lengths of all the strings are no more than minlen, thus they
+       cannot come from lookahead.
+       (Or minlen should take into account lookahead.) 
+  NOTE: Some of this comment is not correct. minlen does now take account
+  of lookahead/behind. Further research is required. -- demerphq
+
+*/
+
+/* A failure to find a constant substring means that there is no need to make
+   an expensive call to REx engine, thus we celebrate a failure.  Similarly,
+   finding a substring too deep into the string means that less calls to
+   regtry() should be needed.
+
+   REx compiler's optimizer found 4 possible hints:
+       a) Anchored substring;
+       b) Fixed substring;
+       c) Whether we are anchored (beginning-of-line or \G);
+       d) First node (of those at offset 0) which may distinguish positions;
+   We use a)b)d) and multiline-part of c), and try to find a position in the
+   string which does not contradict any of them.
+ */
+
+/* Most of decisions we do here should have been done at compile time.
+   The nodes of the REx which we used for the search should have been
+   deleted from the finite automaton. */
+
+char *
+Perl_re_intuit_start(pTHX_ REGEXP * const rx, SV *sv, char *strpos,
+                    char *strend, const U32 flags, re_scream_pos_data *data)
+{
+    dVAR;
+    struct regexp *const prog = ReANY(rx);
+    I32 start_shift = 0;
+    /* Should be nonnegative! */
+    I32 end_shift   = 0;
+    char *s;
+    SV *check;
+    char *strbeg;
+    char *t;
+    const bool utf8_target = (sv && SvUTF8(sv)) ? 1 : 0; /* if no sv we have to assume bytes */
+    I32 ml_anch;
+    char *other_last = NULL;   /* other substr checked before this */
+    char *check_at = NULL;             /* check substr found at this pos */
+    char *checked_upto = NULL;          /* how far into the string we have already checked using find_byclass*/
+    const I32 multiline = prog->extflags & RXf_PMf_MULTILINE;
+    RXi_GET_DECL(prog,progi);
+#ifdef DEBUGGING
+    const char * const i_strpos = strpos;
+#endif
+    GET_RE_DEBUG_FLAGS_DECL;
+
+    PERL_ARGS_ASSERT_RE_INTUIT_START;
+    PERL_UNUSED_ARG(flags);
+    PERL_UNUSED_ARG(data);
+
+    RX_MATCH_UTF8_set(rx,utf8_target);
+
+    if (RX_UTF8(rx)) {
+       PL_reg_flags |= RF_utf8;
+    }
+    DEBUG_EXECUTE_r( 
+        debug_start_match(rx, utf8_target, strpos, strend,
+            sv ? "Guessing start of match in sv for"
+               : "Guessing start of match in string for");
+             );
+
+    /* CHR_DIST() would be more correct here but it makes things slow. */
+    if (prog->minlen > strend - strpos) {
+       DEBUG_EXECUTE_r(PerlIO_printf(Perl_debug_log,
+                             "String too short... [re_intuit_start]\n"));
+       goto fail;
+    }
+                
+    /* XXX we need to pass strbeg as a separate arg: the following is
+     * guesswork and can be wrong... */
+    if (sv && SvPOK(sv)) {
+        char * p   = SvPVX(sv);
+        STRLEN cur = SvCUR(sv); 
+        if (p <= strpos && strpos < p + cur) {
+            strbeg = p;
+            assert(p <= strend && strend <= p + cur);
+        }
+        else
+            strbeg = strend - cur;
+    }
+    else 
+        strbeg = strpos;
+
+    PL_regeol = strend;
+    if (utf8_target) {
+       if (!prog->check_utf8 && prog->check_substr)
+           to_utf8_substr(prog);
+       check = prog->check_utf8;
+    } else {
+       if (!prog->check_substr && prog->check_utf8) {
+           if (! to_byte_substr(prog)) {
+                NON_UTF8_TARGET_BUT_UTF8_REQUIRED(fail);
+            }
+        }
+       check = prog->check_substr;
+    }
+    if (prog->extflags & RXf_ANCH) {   /* Match at beg-of-str or after \n */
+       ml_anch = !( (prog->extflags & RXf_ANCH_SINGLE)
+                    || ( (prog->extflags & RXf_ANCH_BOL)
+                         && !multiline ) );    /* Check after \n? */
+
+       if (!ml_anch) {
+         if ( !(prog->extflags & RXf_ANCH_GPOS) /* Checked by the caller */
+               && !(prog->intflags & PREGf_IMPLICIT) /* not a real BOL */
+              /* SvCUR is not set on references: SvRV and SvPVX_const overlap */
+              && sv && !SvROK(sv)
+              && (strpos != strbeg)) {
+             DEBUG_EXECUTE_r(PerlIO_printf(Perl_debug_log, "Not at start...\n"));
+             goto fail;
+         }
+         if (prog->check_offset_min == prog->check_offset_max
+              && !(prog->extflags & RXf_CANY_SEEN)
+              && ! multiline)   /* /m can cause \n's to match that aren't
+                                   accounted for in the string max length.
+                                   See [perl #115242] */
+          {
+           /* Substring at constant offset from beg-of-str... */
+           I32 slen;
+
+           s = HOP3c(strpos, prog->check_offset_min, strend);
+           
+           if (SvTAIL(check)) {
+               slen = SvCUR(check);    /* >= 1 */
+
+               if ( strend - s > slen || strend - s < slen - 1
+                    || (strend - s == slen && strend[-1] != '\n')) {
+                   DEBUG_EXECUTE_r(PerlIO_printf(Perl_debug_log, "String too long...\n"));
+                   goto fail_finish;
+               }
+               /* Now should match s[0..slen-2] */
+               slen--;
+               if (slen && (*SvPVX_const(check) != *s
+                            || (slen > 1
+                                && memNE(SvPVX_const(check), s, slen)))) {
+                 report_neq:
+                   DEBUG_EXECUTE_r(PerlIO_printf(Perl_debug_log, "String not equal...\n"));
+                   goto fail_finish;
+               }
+           }
+           else if (*SvPVX_const(check) != *s
+                    || ((slen = SvCUR(check)) > 1
+                        && memNE(SvPVX_const(check), s, slen)))
+               goto report_neq;
+           check_at = s;
+           goto success_at_start;
+         }
+       }
+       /* Match is anchored, but substr is not anchored wrt beg-of-str. */
+       s = strpos;
+       start_shift = prog->check_offset_min; /* okay to underestimate on CC */
+       end_shift = prog->check_end_shift;
+       
+       if (!ml_anch) {
+           const I32 end = prog->check_offset_max + CHR_SVLEN(check)
+                                        - (SvTAIL(check) != 0);
+           const I32 eshift = CHR_DIST((U8*)strend, (U8*)s) - end;
+
+           if (end_shift < eshift)
+               end_shift = eshift;
+       }
+    }
+    else {                             /* Can match at random position */
+       ml_anch = 0;
+       s = strpos;
+       start_shift = prog->check_offset_min;  /* okay to underestimate on CC */
+       end_shift = prog->check_end_shift;
+       
+       /* end shift should be non negative here */
+    }
+
+#ifdef QDEBUGGING      /* 7/99: reports of failure (with the older version) */
+    if (end_shift < 0)
+       Perl_croak(aTHX_ "panic: end_shift: %"IVdf" pattern:\n%s\n ",
+                  (IV)end_shift, RX_PRECOMP(prog));
+#endif
+
+  restart:
+    /* Find a possible match in the region s..strend by looking for
+       the "check" substring in the region corrected by start/end_shift. */
+    
+    {
+        I32 srch_start_shift = start_shift;
+        I32 srch_end_shift = end_shift;
+        U8* start_point;
+        U8* end_point;
+        if (srch_start_shift < 0 && strbeg - s > srch_start_shift) {
+           srch_end_shift -= ((strbeg - s) - srch_start_shift); 
+           srch_start_shift = strbeg - s;
+       }
+    DEBUG_OPTIMISE_MORE_r({
+        PerlIO_printf(Perl_debug_log, "Check offset min: %"IVdf" Start shift: %"IVdf" End shift %"IVdf" Real End Shift: %"IVdf"\n",
+            (IV)prog->check_offset_min,
+            (IV)srch_start_shift,
+            (IV)srch_end_shift, 
+            (IV)prog->check_end_shift);
+    });       
+        
+        if (prog->extflags & RXf_CANY_SEEN) {
+            start_point= (U8*)(s + srch_start_shift);
+            end_point= (U8*)(strend - srch_end_shift);
+        } else {
+           start_point= HOP3(s, srch_start_shift, srch_start_shift < 0 ? strbeg : strend);
+            end_point= HOP3(strend, -srch_end_shift, strbeg);
+       }
+       DEBUG_OPTIMISE_MORE_r({
+            PerlIO_printf(Perl_debug_log, "fbm_instr len=%d str=<%.*s>\n", 
+                (int)(end_point - start_point),
+                (int)(end_point - start_point) > 20 ? 20 : (int)(end_point - start_point), 
+                start_point);
+        });
+
+       s = fbm_instr( start_point, end_point,
+                     check, multiline ? FBMrf_MULTILINE : 0);
+    }
+    /* Update the count-of-usability, remove useless subpatterns,
+       unshift s.  */
+
+    DEBUG_EXECUTE_r({
+        RE_PV_QUOTED_DECL(quoted, utf8_target, PERL_DEBUG_PAD_ZERO(0),
+            SvPVX_const(check), RE_SV_DUMPLEN(check), 30);
+        PerlIO_printf(Perl_debug_log, "%s %s substr %s%s%s",
+                         (s ? "Found" : "Did not find"),
+           (check == (utf8_target ? prog->anchored_utf8 : prog->anchored_substr)
+               ? "anchored" : "floating"),
+           quoted,
+           RE_SV_TAIL(check),
+           (s ? " at offset " : "...\n") ); 
+    });
+
+    if (!s)
+       goto fail_finish;
+    /* Finish the diagnostic message */
+    DEBUG_EXECUTE_r(PerlIO_printf(Perl_debug_log, "%ld...\n", (long)(s - i_strpos)) );
+
+    /* XXX dmq: first branch is for positive lookbehind...
+       Our check string is offset from the beginning of the pattern.
+       So we need to do any stclass tests offset forward from that 
+       point. I think. :-(
+     */
+    
+        
+    
+    check_at=s;
+     
+
+    /* Got a candidate.  Check MBOL anchoring, and the *other* substr.
+       Start with the other substr.
+       XXXX no SCREAM optimization yet - and a very coarse implementation
+       XXXX /ttx+/ results in anchored="ttx", floating="x".  floating will
+               *always* match.  Probably should be marked during compile...
+       Probably it is right to do no SCREAM here...
+     */
+
+    if (utf8_target ? (prog->float_utf8 && prog->anchored_utf8)
+                : (prog->float_substr && prog->anchored_substr)) 
+    {
+       /* Take into account the "other" substring. */
+       /* XXXX May be hopelessly wrong for UTF... */
+       if (!other_last)
+           other_last = strpos;
+       if (check == (utf8_target ? prog->float_utf8 : prog->float_substr)) {
+         do_other_anchored:
+           {
+               char * const last = HOP3c(s, -start_shift, strbeg);
+               char *last1, *last2;
+               char * const saved_s = s;
+               SV* must;
+
+               t = s - prog->check_offset_max;
+               if (s - strpos > prog->check_offset_max  /* signed-corrected t > strpos */
+                   && (!utf8_target
+                       || ((t = (char*)reghopmaybe3((U8*)s, -(prog->check_offset_max), (U8*)strpos))
+                           && t > strpos)))
+                   NOOP;
+               else
+                   t = strpos;
+               t = HOP3c(t, prog->anchored_offset, strend);
+               if (t < other_last)     /* These positions already checked */
+                   t = other_last;
+               last2 = last1 = HOP3c(strend, -prog->minlen, strbeg);
+               if (last < last1)
+                   last1 = last;
+                /* XXXX It is not documented what units *_offsets are in.  
+                   We assume bytes, but this is clearly wrong. 
+                   Meaning this code needs to be carefully reviewed for errors.
+                   dmq.
+                  */
+               /* On end-of-str: see comment below. */
+               must = utf8_target ? prog->anchored_utf8 : prog->anchored_substr;
+               if (must == &PL_sv_undef) {
+                   s = (char*)NULL;
+                   DEBUG_r(must = prog->anchored_utf8);        /* for debug */
+               }
+               else
+                   s = fbm_instr(
+                       (unsigned char*)t,
+                       HOP3(HOP3(last1, prog->anchored_offset, strend)
+                               + SvCUR(must), -(SvTAIL(must)!=0), strbeg),
+                       must,
+                       multiline ? FBMrf_MULTILINE : 0
+                   );
+                DEBUG_EXECUTE_r({
+                    RE_PV_QUOTED_DECL(quoted, utf8_target, PERL_DEBUG_PAD_ZERO(0),
+                        SvPVX_const(must), RE_SV_DUMPLEN(must), 30);
+                    PerlIO_printf(Perl_debug_log, "%s anchored substr %s%s",
+                       (s ? "Found" : "Contradicts"),
+                        quoted, RE_SV_TAIL(must));
+                });                
+               
+                           
+               if (!s) {
+                   if (last1 >= last2) {
+                       DEBUG_EXECUTE_r(PerlIO_printf(Perl_debug_log,
+                                               ", giving up...\n"));
+                       goto fail_finish;
+                   }
+                   DEBUG_EXECUTE_r(PerlIO_printf(Perl_debug_log,
+                       ", trying floating at offset %ld...\n",
+                       (long)(HOP3c(saved_s, 1, strend) - i_strpos)));
+                   other_last = HOP3c(last1, prog->anchored_offset+1, strend);
+                   s = HOP3c(last, 1, strend);
+                   goto restart;
+               }
+               else {
+                   DEBUG_EXECUTE_r(PerlIO_printf(Perl_debug_log, " at offset %ld...\n",
+                         (long)(s - i_strpos)));
+                   t = HOP3c(s, -prog->anchored_offset, strbeg);
+                   other_last = HOP3c(s, 1, strend);
+                   s = saved_s;
+                   if (t == strpos)
+                       goto try_at_start;
+                   goto try_at_offset;
+               }
+           }
+       }
+       else {          /* Take into account the floating substring. */
+           char *last, *last1;
+           char * const saved_s = s;
+           SV* must;
+
+           t = HOP3c(s, -start_shift, strbeg);
+           last1 = last =
+               HOP3c(strend, -prog->minlen + prog->float_min_offset, strbeg);
+           if (CHR_DIST((U8*)last, (U8*)t) > prog->float_max_offset)
+               last = HOP3c(t, prog->float_max_offset, strend);
+           s = HOP3c(t, prog->float_min_offset, strend);
+           if (s < other_last)
+               s = other_last;
+ /* XXXX It is not documented what units *_offsets are in.  Assume bytes.  */
+           must = utf8_target ? prog->float_utf8 : prog->float_substr;
+           /* fbm_instr() takes into account exact value of end-of-str
+              if the check is SvTAIL(ed).  Since false positives are OK,
+              and end-of-str is not later than strend we are OK. */
+           if (must == &PL_sv_undef) {
+               s = (char*)NULL;
+               DEBUG_r(must = prog->float_utf8);       /* for debug message */
+           }
+           else
+               s = fbm_instr((unsigned char*)s,
+                             (unsigned char*)last + SvCUR(must)
+                                 - (SvTAIL(must)!=0),
+                             must, multiline ? FBMrf_MULTILINE : 0);
+           DEBUG_EXECUTE_r({
+               RE_PV_QUOTED_DECL(quoted, utf8_target, PERL_DEBUG_PAD_ZERO(0),
+                   SvPVX_const(must), RE_SV_DUMPLEN(must), 30);
+               PerlIO_printf(Perl_debug_log, "%s floating substr %s%s",
+                   (s ? "Found" : "Contradicts"),
+                   quoted, RE_SV_TAIL(must));
+            });
+           if (!s) {
+               if (last1 == last) {
+                   DEBUG_EXECUTE_r(PerlIO_printf(Perl_debug_log,
+                                           ", giving up...\n"));
+                   goto fail_finish;
+               }
+               DEBUG_EXECUTE_r(PerlIO_printf(Perl_debug_log,
+                   ", trying anchored starting at offset %ld...\n",
+                   (long)(saved_s + 1 - i_strpos)));
+               other_last = last;
+               s = HOP3c(t, 1, strend);
+               goto restart;
+           }
+           else {
+               DEBUG_EXECUTE_r(PerlIO_printf(Perl_debug_log, " at offset %ld...\n",
+                     (long)(s - i_strpos)));
+               other_last = s; /* Fix this later. --Hugo */
+               s = saved_s;
+               if (t == strpos)
+                   goto try_at_start;
+               goto try_at_offset;
+           }
+       }
+    }
+
+    
+    t= (char*)HOP3( s, -prog->check_offset_max, (prog->check_offset_max<0) ? strend : strpos);
+        
+    DEBUG_OPTIMISE_MORE_r(
+        PerlIO_printf(Perl_debug_log, 
+            "Check offset min:%"IVdf" max:%"IVdf" S:%"IVdf" t:%"IVdf" D:%"IVdf" end:%"IVdf"\n",
+            (IV)prog->check_offset_min,
+            (IV)prog->check_offset_max,
+            (IV)(s-strpos),
+            (IV)(t-strpos),
+            (IV)(t-s),
+            (IV)(strend-strpos)
+        )
+    );
+
+    if (s - strpos > prog->check_offset_max  /* signed-corrected t > strpos */
+        && (!utf8_target
+           || ((t = (char*)reghopmaybe3((U8*)s, -prog->check_offset_max, (U8*) ((prog->check_offset_max<0) ? strend : strpos)))
+                && t > strpos))) 
+    {
+       /* Fixed substring is found far enough so that the match
+          cannot start at strpos. */
+      try_at_offset:
+       if (ml_anch && t[-1] != '\n') {
+           /* Eventually fbm_*() should handle this, but often
+              anchored_offset is not 0, so this check will not be wasted. */
+           /* XXXX In the code below we prefer to look for "^" even in
+              presence of anchored substrings.  And we search even
+              beyond the found float position.  These pessimizations
+              are historical artefacts only.  */
+         find_anchor:
+           while (t < strend - prog->minlen) {
+               if (*t == '\n') {
+                   if (t < check_at - prog->check_offset_min) {
+                       if (utf8_target ? prog->anchored_utf8 : prog->anchored_substr) {
+                           /* Since we moved from the found position,
+                              we definitely contradict the found anchored
+                              substr.  Due to the above check we do not
+                              contradict "check" substr.
+                              Thus we can arrive here only if check substr
+                              is float.  Redo checking for "other"=="fixed".
+                            */
+                           strpos = t + 1;                     
+                           DEBUG_EXECUTE_r(PerlIO_printf(Perl_debug_log, "Found /%s^%s/m at offset %ld, rescanning for anchored from offset %ld...\n",
+                               PL_colors[0], PL_colors[1], (long)(strpos - i_strpos), (long)(strpos - i_strpos + prog->anchored_offset)));
+                           goto do_other_anchored;
+                       }
+                       /* We don't contradict the found floating substring. */
+                       /* XXXX Why not check for STCLASS? */
+                       s = t + 1;
+                       DEBUG_EXECUTE_r(PerlIO_printf(Perl_debug_log, "Found /%s^%s/m at offset %ld...\n",
+                           PL_colors[0], PL_colors[1], (long)(s - i_strpos)));
+                       goto set_useful;
+                   }
+                   /* Position contradicts check-string */
+                   /* XXXX probably better to look for check-string
+                      than for "\n", so one should lower the limit for t? */
+                   DEBUG_EXECUTE_r(PerlIO_printf(Perl_debug_log, "Found /%s^%s/m, restarting lookup for check-string at offset %ld...\n",
+                       PL_colors[0], PL_colors[1], (long)(t + 1 - i_strpos)));
+                   other_last = strpos = s = t + 1;
+                   goto restart;
+               }
+               t++;
+           }
+           DEBUG_EXECUTE_r(PerlIO_printf(Perl_debug_log, "Did not find /%s^%s/m...\n",
+                       PL_colors[0], PL_colors[1]));
+           goto fail_finish;
+       }
+       else {
+           DEBUG_EXECUTE_r(PerlIO_printf(Perl_debug_log, "Starting position does not contradict /%s^%s/m...\n",
+                       PL_colors[0], PL_colors[1]));
+       }
+       s = t;
+      set_useful:
+       ++BmUSEFUL(utf8_target ? prog->check_utf8 : prog->check_substr);        /* hooray/5 */
+    }
+    else {
+       /* The found string does not prohibit matching at strpos,
+          - no optimization of calling REx engine can be performed,
+          unless it was an MBOL and we are not after MBOL,
+          or a future STCLASS check will fail this. */
+      try_at_start:
+       /* Even in this situation we may use MBOL flag if strpos is offset
+          wrt the start of the string. */
+       if (ml_anch && sv && !SvROK(sv) /* See prev comment on SvROK */
+           && (strpos != strbeg) && strpos[-1] != '\n'
+           /* May be due to an implicit anchor of m{.*foo}  */
+           && !(prog->intflags & PREGf_IMPLICIT))
+       {
+           t = strpos;
+           goto find_anchor;
+       }
+       DEBUG_EXECUTE_r( if (ml_anch)
+           PerlIO_printf(Perl_debug_log, "Position at offset %ld does not contradict /%s^%s/m...\n",
+                         (long)(strpos - i_strpos), PL_colors[0], PL_colors[1]);
+       );
+      success_at_start:
+       if (!(prog->intflags & PREGf_NAUGHTY)   /* XXXX If strpos moved? */
+           && (utf8_target ? (
+               prog->check_utf8                /* Could be deleted already */
+               && --BmUSEFUL(prog->check_utf8) < 0
+               && (prog->check_utf8 == prog->float_utf8)
+           ) : (
+               prog->check_substr              /* Could be deleted already */
+               && --BmUSEFUL(prog->check_substr) < 0
+               && (prog->check_substr == prog->float_substr)
+           )))
+       {
+           /* If flags & SOMETHING - do not do it many times on the same match */
+           DEBUG_EXECUTE_r(PerlIO_printf(Perl_debug_log, "... Disabling check substring...\n"));
+           /* XXX Does the destruction order has to change with utf8_target? */
+           SvREFCNT_dec(utf8_target ? prog->check_utf8 : prog->check_substr);
+           SvREFCNT_dec(utf8_target ? prog->check_substr : prog->check_utf8);
+           prog->check_substr = prog->check_utf8 = NULL;       /* disable */
+           prog->float_substr = prog->float_utf8 = NULL;       /* clear */
+           check = NULL;                       /* abort */
+           s = strpos;
+           /* XXXX If the check string was an implicit check MBOL, then we need to unset the relevant flag
+                   see http://bugs.activestate.com/show_bug.cgi?id=87173 */
+           if (prog->intflags & PREGf_IMPLICIT)
+               prog->extflags &= ~RXf_ANCH_MBOL;
+           /* XXXX This is a remnant of the old implementation.  It
+                   looks wasteful, since now INTUIT can use many
+                   other heuristics. */
+           prog->extflags &= ~RXf_USE_INTUIT;
+           /* XXXX What other flags might need to be cleared in this branch? */
+       }
+       else
+           s = strpos;
+    }
+
+    /* Last resort... */
+    /* XXXX BmUSEFUL already changed, maybe multiple change is meaningful... */
+    /* trie stclasses are too expensive to use here, we are better off to
+       leave it to regmatch itself */
+    if (progi->regstclass && PL_regkind[OP(progi->regstclass)]!=TRIE) {
+       /* minlen == 0 is possible if regstclass is \b or \B,
+          and the fixed substr is ''$.
+          Since minlen is already taken into account, s+1 is before strend;
+          accidentally, minlen >= 1 guaranties no false positives at s + 1
+          even for \b or \B.  But (minlen? 1 : 0) below assumes that
+          regstclass does not come from lookahead...  */
+       /* If regstclass takes bytelength more than 1: If charlength==1, OK.
+          This leaves EXACTF-ish only, which are dealt with in find_byclass().  */
+        const U8* const str = (U8*)STRING(progi->regstclass);
+        const int cl_l = (PL_regkind[OP(progi->regstclass)] == EXACT
+                   ? CHR_DIST(str+STR_LEN(progi->regstclass), str)
+                   : 1);
+       char * endpos;
+       if (prog->anchored_substr || prog->anchored_utf8 || ml_anch)
+            endpos= HOP3c(s, (prog->minlen ? cl_l : 0), strend);
+        else if (prog->float_substr || prog->float_utf8)
+           endpos= HOP3c(HOP3c(check_at, -start_shift, strbeg), cl_l, strend);
+        else 
+            endpos= strend;
+                   
+        if (checked_upto < s)
+           checked_upto = s;
+        DEBUG_EXECUTE_r(PerlIO_printf(Perl_debug_log, "start_shift: %"IVdf" check_at: %"IVdf" s: %"IVdf" endpos: %"IVdf" checked_upto: %"IVdf"\n",
+                                      (IV)start_shift, (IV)(check_at - strbeg), (IV)(s - strbeg), (IV)(endpos - strbeg), (IV)(checked_upto- strbeg)));
+
+       t = s;
+        s = find_byclass(prog, progi->regstclass, checked_upto, endpos, NULL);
+       if (s) {
+           checked_upto = s;
+       } else {
+#ifdef DEBUGGING
+           const char *what = NULL;
+#endif
+           if (endpos == strend) {
+               DEBUG_EXECUTE_r( PerlIO_printf(Perl_debug_log,
+                               "Could not match STCLASS...\n") );
+               goto fail;
+           }
+           DEBUG_EXECUTE_r( PerlIO_printf(Perl_debug_log,
+                                  "This position contradicts STCLASS...\n") );
+           if ((prog->extflags & RXf_ANCH) && !ml_anch)
+               goto fail;
+           checked_upto = HOPBACKc(endpos, start_shift);
+           DEBUG_EXECUTE_r(PerlIO_printf(Perl_debug_log, "start_shift: %"IVdf" check_at: %"IVdf" endpos: %"IVdf" checked_upto: %"IVdf"\n",
+                                      (IV)start_shift, (IV)(check_at - strbeg), (IV)(endpos - strbeg), (IV)(checked_upto- strbeg)));
+           /* Contradict one of substrings */
+           if (prog->anchored_substr || prog->anchored_utf8) {
+               if ((utf8_target ? prog->anchored_utf8 : prog->anchored_substr) == check) {
+                   DEBUG_EXECUTE_r( what = "anchored" );
+                 hop_and_restart:
+                   s = HOP3c(t, 1, strend);
+                   if (s + start_shift + end_shift > strend) {
+                       /* XXXX Should be taken into account earlier? */
+                       DEBUG_EXECUTE_r( PerlIO_printf(Perl_debug_log,
+                                              "Could not match STCLASS...\n") );
+                       goto fail;
+                   }
+                   if (!check)
+                       goto giveup;
+                   DEBUG_EXECUTE_r( PerlIO_printf(Perl_debug_log,
+                               "Looking for %s substr starting at offset %ld...\n",
+                                what, (long)(s + start_shift - i_strpos)) );
+                   goto restart;
+               }
+               /* Have both, check_string is floating */
+               if (t + start_shift >= check_at) /* Contradicts floating=check */
+                   goto retry_floating_check;
+               /* Recheck anchored substring, but not floating... */
+               s = check_at;
+               if (!check)
+                   goto giveup;
+               DEBUG_EXECUTE_r( PerlIO_printf(Perl_debug_log,
+                         "Looking for anchored substr starting at offset %ld...\n",
+                         (long)(other_last - i_strpos)) );
+               goto do_other_anchored;
+           }
+           /* Another way we could have checked stclass at the
+               current position only: */
+           if (ml_anch) {
+               s = t = t + 1;
+               if (!check)
+                   goto giveup;
+               DEBUG_EXECUTE_r( PerlIO_printf(Perl_debug_log,
+                         "Looking for /%s^%s/m starting at offset %ld...\n",
+                         PL_colors[0], PL_colors[1], (long)(t - i_strpos)) );
+               goto try_at_offset;
+           }
+           if (!(utf8_target ? prog->float_utf8 : prog->float_substr)) /* Could have been deleted */
+               goto fail;
+           /* Check is floating substring. */
+         retry_floating_check:
+           t = check_at - start_shift;
+           DEBUG_EXECUTE_r( what = "floating" );
+           goto hop_and_restart;
+       }
+       if (t != s) {
+            DEBUG_EXECUTE_r(PerlIO_printf(Perl_debug_log,
+                       "By STCLASS: moving %ld --> %ld\n",
+                                  (long)(t - i_strpos), (long)(s - i_strpos))
+                   );
+        }
+        else {
+            DEBUG_EXECUTE_r(PerlIO_printf(Perl_debug_log,
+                                  "Does not contradict STCLASS...\n"); 
+                   );
+        }
+    }
+  giveup:
+    DEBUG_EXECUTE_r(PerlIO_printf(Perl_debug_log, "%s%s:%s match at offset %ld\n",
+                         PL_colors[4], (check ? "Guessed" : "Giving up"),
+                         PL_colors[5], (long)(s - i_strpos)) );
+    return s;
+
+  fail_finish:                         /* Substring not found */
+    if (prog->check_substr || prog->check_utf8)                /* could be removed already */
+       BmUSEFUL(utf8_target ? prog->check_utf8 : prog->check_substr) += 5; /* hooray */
+  fail:
+    DEBUG_EXECUTE_r(PerlIO_printf(Perl_debug_log, "%sMatch rejected by optimizer%s\n",
+                         PL_colors[4], PL_colors[5]));
+    return NULL;
+}
+
+#define DECL_TRIE_TYPE(scan) \
+    const enum { trie_plain, trie_utf8, trie_utf8_fold, trie_latin_utf8_fold } \
+                    trie_type = ((scan->flags == EXACT) \
+                              ? (utf8_target ? trie_utf8 : trie_plain) \
+                              : (utf8_target ? trie_utf8_fold : trie_latin_utf8_fold))
+
+#define REXEC_TRIE_READ_CHAR(trie_type, trie, widecharmap, uc, uscan, len,          \
+uvc, charid, foldlen, foldbuf, uniflags) STMT_START {                               \
+    STRLEN skiplen;                                                                 \
+    switch (trie_type) {                                                            \
+    case trie_utf8_fold:                                                            \
+        if ( foldlen>0 ) {                                                          \
+            uvc = utf8n_to_uvuni( (const U8*) uscan, UTF8_MAXLEN, &len, uniflags ); \
+            foldlen -= len;                                                         \
+            uscan += len;                                                           \
+            len=0;                                                                  \
+        } else {                                                                    \
+            uvc = to_utf8_fold( (const U8*) uc, foldbuf, &foldlen );                \
+            len = UTF8SKIP(uc);                                                     \
+            skiplen = UNISKIP( uvc );                                               \
+            foldlen -= skiplen;                                                     \
+            uscan = foldbuf + skiplen;                                              \
+        }                                                                           \
+        break;                                                                      \
+    case trie_latin_utf8_fold:                                                      \
+        if ( foldlen>0 ) {                                                          \
+            uvc = utf8n_to_uvuni( (const U8*) uscan, UTF8_MAXLEN, &len, uniflags ); \
+            foldlen -= len;                                                         \
+            uscan += len;                                                           \
+            len=0;                                                                  \
+        } else {                                                                    \
+            len = 1;                                                                \
+            uvc = _to_fold_latin1( (U8) *uc, foldbuf, &foldlen, 1);                 \
+            skiplen = UNISKIP( uvc );                                               \
+            foldlen -= skiplen;                                                     \
+            uscan = foldbuf + skiplen;                                              \
+        }                                                                           \
+        break;                                                                      \
+    case trie_utf8:                                                                 \
+        uvc = utf8n_to_uvuni( (const U8*) uc, UTF8_MAXLEN, &len, uniflags );        \
+        break;                                                                      \
+    case trie_plain:                                                                \
+        uvc = (UV)*uc;                                                              \
+        len = 1;                                                                    \
+    }                                                                               \
+    if (uvc < 256) {                                                                \
+        charid = trie->charmap[ uvc ];                                              \
+    }                                                                               \
+    else {                                                                          \
+        charid = 0;                                                                 \
+        if (widecharmap) {                                                          \
+            SV** const svpp = hv_fetch(widecharmap,                                 \
+                        (char*)&uvc, sizeof(UV), 0);                                \
+            if (svpp)                                                               \
+                charid = (U16)SvIV(*svpp);                                          \
+        }                                                                           \
+    }                                                                               \
+} STMT_END
+
+#define REXEC_FBC_EXACTISH_SCAN(CoNd)                     \
+STMT_START {                                              \
+    while (s <= e) {                                      \
+       if ( (CoNd)                                       \
+            && (ln == 1 || folder(s, pat_string, ln))    \
+            && (!reginfo || regtry(reginfo, &s)) )       \
+           goto got_it;                                  \
+       s++;                                              \
+    }                                                     \
+} STMT_END
+
+#define REXEC_FBC_UTF8_SCAN(CoDe)                     \
+STMT_START {                                          \
+    while (s < strend && s + (uskip = UTF8SKIP(s)) <= strend) {     \
+       CoDe                                          \
+       s += uskip;                                   \
+    }                                                 \
+} STMT_END
+
+#define REXEC_FBC_SCAN(CoDe)                          \
+STMT_START {                                          \
+    while (s < strend) {                              \
+       CoDe                                          \
+       s++;                                          \
+    }                                                 \
+} STMT_END
+
+#define REXEC_FBC_UTF8_CLASS_SCAN(CoNd)               \
+REXEC_FBC_UTF8_SCAN(                                  \
+    if (CoNd) {                                       \
+       if (tmp && (!reginfo || regtry(reginfo, &s)))  \
+           goto got_it;                              \
+       else                                          \
+           tmp = doevery;                            \
+    }                                                 \
+    else                                              \
+       tmp = 1;                                      \
+)
+
+#define REXEC_FBC_CLASS_SCAN(CoNd)                    \
+REXEC_FBC_SCAN(                                       \
+    if (CoNd) {                                       \
+       if (tmp && (!reginfo || regtry(reginfo, &s)))  \
+           goto got_it;                              \
+       else                                          \
+           tmp = doevery;                            \
+    }                                                 \
+    else                                              \
+       tmp = 1;                                      \
+)
+
+#define REXEC_FBC_TRYIT               \
+if ((!reginfo || regtry(reginfo, &s))) \
+    goto got_it
+
+#define REXEC_FBC_CSCAN(CoNdUtF8,CoNd)                         \
+    if (utf8_target) {                                             \
+       REXEC_FBC_UTF8_CLASS_SCAN(CoNdUtF8);                   \
+    }                                                          \
+    else {                                                     \
+       REXEC_FBC_CLASS_SCAN(CoNd);                            \
+    }
+    
+#define REXEC_FBC_CSCAN_PRELOAD(UtFpReLoAd,CoNdUtF8,CoNd)      \
+    if (utf8_target) {                                             \
+       UtFpReLoAd;                                            \
+       REXEC_FBC_UTF8_CLASS_SCAN(CoNdUtF8);                   \
+    }                                                          \
+    else {                                                     \
+       REXEC_FBC_CLASS_SCAN(CoNd);                            \
+    }
+
+#define REXEC_FBC_CSCAN_TAINT(CoNdUtF8,CoNd)                   \
+    PL_reg_flags |= RF_tainted;                                \
+    if (utf8_target) {                                             \
+       REXEC_FBC_UTF8_CLASS_SCAN(CoNdUtF8);                   \
+    }                                                          \
+    else {                                                     \
+       REXEC_FBC_CLASS_SCAN(CoNd);                            \
+    }
+
+#define DUMP_EXEC_POS(li,s,doutf8) \
+    dump_exec_pos(li,s,(PL_regeol),(PL_bostr),(PL_reg_starttry),doutf8)
+
+
+#define UTF8_NOLOAD(TEST_NON_UTF8, IF_SUCCESS, IF_FAIL) \
+       tmp = (s != PL_bostr) ? UCHARAT(s - 1) : '\n';                         \
+       tmp = TEST_NON_UTF8(tmp);                                              \
+       REXEC_FBC_UTF8_SCAN(                                                   \
+           if (tmp == ! TEST_NON_UTF8((U8) *s)) { \
+               tmp = !tmp;                                                    \
+               IF_SUCCESS;                                                    \
+           }                                                                  \
+           else {                                                             \
+               IF_FAIL;                                                       \
+           }                                                                  \
+       );                                                                     \
+
+#define UTF8_LOAD(TeSt1_UtF8, TeSt2_UtF8, IF_SUCCESS, IF_FAIL) \
+       if (s == PL_bostr) {                                                   \
+           tmp = '\n';                                                        \
+       }                                                                      \
+       else {                                                                 \
+           U8 * const r = reghop3((U8*)s, -1, (U8*)PL_bostr);                 \
+           tmp = utf8n_to_uvchr(r, UTF8SKIP(r), 0, UTF8_ALLOW_DEFAULT);       \
+       }                                                                      \
+       tmp = TeSt1_UtF8;                                                      \
+       LOAD_UTF8_CHARCLASS_ALNUM();                                                                \
+       REXEC_FBC_UTF8_SCAN(                                                   \
+           if (tmp == ! (TeSt2_UtF8)) { \
+               tmp = !tmp;                                                    \
+               IF_SUCCESS;                                                    \
+           }                                                                  \
+           else {                                                             \
+               IF_FAIL;                                                       \
+           }                                                                  \
+       );                                                                     \
+
+/* The only difference between the BOUND and NBOUND cases is that
+ * REXEC_FBC_TRYIT is called when matched in BOUND, and when non-matched in
+ * NBOUND.  This is accomplished by passing it in either the if or else clause,
+ * with the other one being empty */
+#define FBC_BOUND(TEST_NON_UTF8, TEST1_UTF8, TEST2_UTF8) \
+    FBC_BOUND_COMMON(UTF8_LOAD(TEST1_UTF8, TEST2_UTF8, REXEC_FBC_TRYIT, PLACEHOLDER), TEST_NON_UTF8, REXEC_FBC_TRYIT, PLACEHOLDER)
+
+#define FBC_BOUND_NOLOAD(TEST_NON_UTF8, TEST1_UTF8, TEST2_UTF8) \
+    FBC_BOUND_COMMON(UTF8_NOLOAD(TEST_NON_UTF8, REXEC_FBC_TRYIT, PLACEHOLDER), TEST_NON_UTF8, REXEC_FBC_TRYIT, PLACEHOLDER)
+
+#define FBC_NBOUND(TEST_NON_UTF8, TEST1_UTF8, TEST2_UTF8) \
+    FBC_BOUND_COMMON(UTF8_LOAD(TEST1_UTF8, TEST2_UTF8, PLACEHOLDER, REXEC_FBC_TRYIT), TEST_NON_UTF8, PLACEHOLDER, REXEC_FBC_TRYIT)
+
+#define FBC_NBOUND_NOLOAD(TEST_NON_UTF8, TEST1_UTF8, TEST2_UTF8) \
+    FBC_BOUND_COMMON(UTF8_NOLOAD(TEST_NON_UTF8, PLACEHOLDER, REXEC_FBC_TRYIT), TEST_NON_UTF8, PLACEHOLDER, REXEC_FBC_TRYIT)
+
+
+/* Common to the BOUND and NBOUND cases.  Unfortunately the UTF8 tests need to
+ * be passed in completely with the variable name being tested, which isn't
+ * such a clean interface, but this is easier to read than it was before.  We
+ * are looking for the boundary (or non-boundary between a word and non-word
+ * character.  The utf8 and non-utf8 cases have the same logic, but the details
+ * must be different.  Find the "wordness" of the character just prior to this
+ * one, and compare it with the wordness of this one.  If they differ, we have
+ * a boundary.  At the beginning of the string, pretend that the previous
+ * character was a new-line */
+#define FBC_BOUND_COMMON(UTF8_CODE, TEST_NON_UTF8, IF_SUCCESS, IF_FAIL) \
+    if (utf8_target) {                                                         \
+               UTF8_CODE \
+    }                                                                          \
+    else {  /* Not utf8 */                                                     \
+       tmp = (s != PL_bostr) ? UCHARAT(s - 1) : '\n';                         \
+       tmp = TEST_NON_UTF8(tmp);                                              \
+       REXEC_FBC_SCAN(                                                        \
+           if (tmp == ! TEST_NON_UTF8((U8) *s)) {                             \
+               tmp = !tmp;                                                    \
+               IF_SUCCESS;                                                    \
+           }                                                                  \
+           else {                                                             \
+               IF_FAIL;                                                       \
+           }                                                                  \
+       );                                                                     \
+    }                                                                          \
+    if ((!prog->minlen && tmp) && (!reginfo || regtry(reginfo, &s)))           \
+       goto got_it;
+
+/* We know what class REx starts with.  Try to find this position... */
+/* if reginfo is NULL, its a dryrun */
+/* annoyingly all the vars in this routine have different names from their counterparts
+   in regmatch. /grrr */
+
+STATIC char *
+S_find_byclass(pTHX_ regexp * prog, const regnode *c, char *s, 
+    const char *strend, regmatch_info *reginfo)
+{
+       dVAR;
+       const I32 doevery = (prog->intflags & PREGf_SKIP) == 0;
+       char *pat_string;   /* The pattern's exactish string */
+       char *pat_end;      /* ptr to end char of pat_string */
+       re_fold_t folder;       /* Function for computing non-utf8 folds */
+       const U8 *fold_array;   /* array for folding ords < 256 */
+       STRLEN ln;
+       STRLEN lnc;
+       STRLEN uskip;
+       U8 c1;
+       U8 c2;
+       char *e;
+       I32 tmp = 1;    /* Scratch variable? */
+       const bool utf8_target = PL_reg_match_utf8;
+       UV utf8_fold_flags = 0;
+        RXi_GET_DECL(prog,progi);
+
+       PERL_ARGS_ASSERT_FIND_BYCLASS;
+        
+       /* We know what class it must start with. */
+       switch (OP(c)) {
+       case ANYOF:
+           if (utf8_target) {
+               REXEC_FBC_UTF8_CLASS_SCAN(
+                          reginclass(prog, c, (U8*)s, utf8_target));
+           }
+           else {
+               REXEC_FBC_CLASS_SCAN(REGINCLASS(prog, c, (U8*)s));
+           }
+           break;
+       case CANY:
+           REXEC_FBC_SCAN(
+               if (tmp && (!reginfo || regtry(reginfo, &s)))
+                   goto got_it;
+               else
+                   tmp = doevery;
+           );
+           break;
+
+       case EXACTFA:
+           if (UTF_PATTERN || utf8_target) {
+               utf8_fold_flags = FOLDEQ_UTF8_NOMIX_ASCII;
+               goto do_exactf_utf8;
+           }
+           fold_array = PL_fold_latin1;    /* Latin1 folds are not affected by */
+           folder = foldEQ_latin1;         /* /a, except the sharp s one which */
+           goto do_exactf_non_utf8;        /* isn't dealt with by these */
+
+       case EXACTF:
+           if (utf8_target) {
+
+               /* regcomp.c already folded this if pattern is in UTF-8 */
+               utf8_fold_flags = 0;
+               goto do_exactf_utf8;
+           }
+           fold_array = PL_fold;
+           folder = foldEQ;
+           goto do_exactf_non_utf8;
+
+       case EXACTFL:
+           if (UTF_PATTERN || utf8_target) {
+               utf8_fold_flags = FOLDEQ_UTF8_LOCALE;
+               goto do_exactf_utf8;
+           }
+           fold_array = PL_fold_locale;
+           folder = foldEQ_locale;
+           goto do_exactf_non_utf8;
+
+       case EXACTFU_SS:
+           if (UTF_PATTERN) {
+               utf8_fold_flags = FOLDEQ_S2_ALREADY_FOLDED;
+           }
+           goto do_exactf_utf8;
+
+       case EXACTFU_TRICKYFOLD:
+       case EXACTFU:
+           if (UTF_PATTERN || utf8_target) {
+               utf8_fold_flags = (UTF_PATTERN) ? FOLDEQ_S2_ALREADY_FOLDED : 0;
+               goto do_exactf_utf8;
+           }
+
+           /* Any 'ss' in the pattern should have been replaced by regcomp,
+            * so we don't have to worry here about this single special case
+            * in the Latin1 range */
+           fold_array = PL_fold_latin1;
+           folder = foldEQ_latin1;
+
+           /* FALL THROUGH */
+
+       do_exactf_non_utf8: /* Neither pattern nor string are UTF8, and there
+                              are no glitches with fold-length differences
+                              between the target string and pattern */
+
+           /* The idea in the non-utf8 EXACTF* cases is to first find the
+            * first character of the EXACTF* node and then, if necessary,
+            * case-insensitively compare the full text of the node.  c1 is the
+            * first character.  c2 is its fold.  This logic will not work for
+            * Unicode semantics and the german sharp ss, which hence should
+            * not be compiled into a node that gets here. */
+           pat_string = STRING(c);
+           ln  = STR_LEN(c);   /* length to match in octets/bytes */
+
+           /* We know that we have to match at least 'ln' bytes (which is the
+            * same as characters, since not utf8).  If we have to match 3
+            * characters, and there are only 2 availabe, we know without
+            * trying that it will fail; so don't start a match past the
+            * required minimum number from the far end */
+           e = HOP3c(strend, -((I32)ln), s);
+
+           if (!reginfo && e < s) {
+               e = s;                  /* Due to minlen logic of intuit() */
+           }
+
+           c1 = *pat_string;
+           c2 = fold_array[c1];
+           if (c1 == c2) { /* If char and fold are the same */
+               REXEC_FBC_EXACTISH_SCAN(*(U8*)s == c1);
+           }
+           else {
+               REXEC_FBC_EXACTISH_SCAN(*(U8*)s == c1 || *(U8*)s == c2);
+           }
+           break;
+
+       do_exactf_utf8:
+       {
+           unsigned expansion;
+
+
+           /* If one of the operands is in utf8, we can't use the simpler
+            * folding above, due to the fact that many different characters
+            * can have the same fold, or portion of a fold, or different-
+            * length fold */
+           pat_string = STRING(c);
+           ln  = STR_LEN(c);   /* length to match in octets/bytes */
+           pat_end = pat_string + ln;
+           lnc = (UTF_PATTERN) /* length to match in characters */
+                   ? utf8_length((U8 *) pat_string, (U8 *) pat_end)
+                   : ln;
+
+           /* We have 'lnc' characters to match in the pattern, but because of
+            * multi-character folding, each character in the target can match
+            * up to 3 characters (Unicode guarantees it will never exceed
+            * this) if it is utf8-encoded; and up to 2 if not (based on the
+            * fact that the Latin 1 folds are already determined, and the
+            * only multi-char fold in that range is the sharp-s folding to
+            * 'ss'.  Thus, a pattern character can match as little as 1/3 of a
+            * string character.  Adjust lnc accordingly, rounding up, so that
+            * if we need to match at least 4+1/3 chars, that really is 5. */
+           expansion = (utf8_target) ? UTF8_MAX_FOLD_CHAR_EXPAND : 2;
+           lnc = (lnc + expansion - 1) / expansion;
+
+           /* As in the non-UTF8 case, if we have to match 3 characters, and
+            * only 2 are left, it's guaranteed to fail, so don't start a
+            * match that would require us to go beyond the end of the string
+            */
+           e = HOP3c(strend, -((I32)lnc), s);
+
+           if (!reginfo && e < s) {
+               e = s;                  /* Due to minlen logic of intuit() */
+           }
+
+           /* XXX Note that we could recalculate e to stop the loop earlier,
+            * as the worst case expansion above will rarely be met, and as we
+            * go along we would usually find that e moves further to the left.
+            * This would happen only after we reached the point in the loop
+            * where if there were no expansion we should fail.  Unclear if
+            * worth the expense */
+
+           while (s <= e) {
+               char *my_strend= (char *)strend;
+               if (foldEQ_utf8_flags(s, &my_strend, 0,  utf8_target,
+                     pat_string, NULL, ln, cBOOL(UTF_PATTERN), utf8_fold_flags)
+                   && (!reginfo || regtry(reginfo, &s)) )
+               {
+                   goto got_it;
+               }
+               s += (utf8_target) ? UTF8SKIP(s) : 1;
+           }
+           break;
+       }
+       case BOUNDL:
+           PL_reg_flags |= RF_tainted;
+           FBC_BOUND(isALNUM_LC,
+                     isALNUM_LC_uvchr(UNI_TO_NATIVE(tmp)),
+                     isALNUM_LC_utf8((U8*)s));
+           break;
+       case NBOUNDL:
+           PL_reg_flags |= RF_tainted;
+           FBC_NBOUND(isALNUM_LC,
+                      isALNUM_LC_uvchr(UNI_TO_NATIVE(tmp)),
+                      isALNUM_LC_utf8((U8*)s));
+           break;
+       case BOUND:
+           FBC_BOUND(isWORDCHAR,
+                     isALNUM_uni(tmp),
+                     cBOOL(swash_fetch(PL_utf8_alnum, (U8*)s, utf8_target)));
+           break;
+       case BOUNDA:
+           FBC_BOUND_NOLOAD(isWORDCHAR_A,
+                            isWORDCHAR_A(tmp),
+                            isWORDCHAR_A((U8*)s));
+           break;
+       case NBOUND:
+           FBC_NBOUND(isWORDCHAR,
+                      isALNUM_uni(tmp),
+                      cBOOL(swash_fetch(PL_utf8_alnum, (U8*)s, utf8_target)));
+           break;
+       case NBOUNDA:
+           FBC_NBOUND_NOLOAD(isWORDCHAR_A,
+                             isWORDCHAR_A(tmp),
+                             isWORDCHAR_A((U8*)s));
+           break;
+       case BOUNDU:
+           FBC_BOUND(isWORDCHAR_L1,
+                     isALNUM_uni(tmp),
+                     cBOOL(swash_fetch(PL_utf8_alnum, (U8*)s, utf8_target)));
+           break;
+       case NBOUNDU:
+           FBC_NBOUND(isWORDCHAR_L1,
+                      isALNUM_uni(tmp),
+                      cBOOL(swash_fetch(PL_utf8_alnum, (U8*)s, utf8_target)));
+           break;
+       case ALNUML:
+           REXEC_FBC_CSCAN_TAINT(
+               isALNUM_LC_utf8((U8*)s),
+               isALNUM_LC(*s)
+           );
+           break;
+       case ALNUMU:
+           REXEC_FBC_CSCAN_PRELOAD(
+               LOAD_UTF8_CHARCLASS_ALNUM(),
+               swash_fetch(PL_utf8_alnum,(U8*)s, utf8_target),
+                isWORDCHAR_L1((U8) *s)
+           );
+           break;
+       case ALNUM:
+           REXEC_FBC_CSCAN_PRELOAD(
+               LOAD_UTF8_CHARCLASS_ALNUM(),
+               swash_fetch(PL_utf8_alnum,(U8*)s, utf8_target),
+                isWORDCHAR((U8) *s)
+           );
+           break;
+       case ALNUMA:
+           /* Don't need to worry about utf8, as it can match only a single
+            * byte invariant character */
+           REXEC_FBC_CLASS_SCAN( isWORDCHAR_A(*s));
+           break;
+       case NALNUMU:
+           REXEC_FBC_CSCAN_PRELOAD(
+               LOAD_UTF8_CHARCLASS_ALNUM(),
+               !swash_fetch(PL_utf8_alnum,(U8*)s, utf8_target),
+                ! isWORDCHAR_L1((U8) *s)
+           );
+           break;
+       case NALNUM:
+           REXEC_FBC_CSCAN_PRELOAD(
+               LOAD_UTF8_CHARCLASS_ALNUM(),
+               !swash_fetch(PL_utf8_alnum, (U8*)s, utf8_target),
+                ! isALNUM(*s)
+           );
+           break;
+       case NALNUMA:
+           REXEC_FBC_CSCAN(
+               !isWORDCHAR_A(*s),
+               !isWORDCHAR_A(*s)
+           );
+           break;
+       case NALNUML:
+           REXEC_FBC_CSCAN_TAINT(
+               !isALNUM_LC_utf8((U8*)s),
+               !isALNUM_LC(*s)
+           );
+           break;
+       case SPACEU:
+           REXEC_FBC_CSCAN(
+               is_XPERLSPACE_utf8(s),
+                isSPACE_L1((U8) *s)
+           );
+           break;
+       case SPACE:
+           REXEC_FBC_CSCAN(
+               is_XPERLSPACE_utf8(s),
+                isSPACE((U8) *s)
+           );
+           break;
+       case SPACEA:
+           /* Don't need to worry about utf8, as it can match only a single
+            * byte invariant character */
+           REXEC_FBC_CLASS_SCAN( isSPACE_A(*s));
+           break;
+       case SPACEL:
+           REXEC_FBC_CSCAN_TAINT(
+               isSPACE_LC_utf8((U8*)s),
+               isSPACE_LC(*s)
+           );
+           break;
+       case NSPACEU:
+           REXEC_FBC_CSCAN(
+               ! is_XPERLSPACE_utf8(s),
+                ! isSPACE_L1((U8) *s)
+           );
+           break;
+       case NSPACE:
+           REXEC_FBC_CSCAN(
+               ! is_XPERLSPACE_utf8(s),
+                ! isSPACE((U8) *s)
+           );
+           break;
+       case NSPACEA:
+           REXEC_FBC_CSCAN(
+               !isSPACE_A(*s),
+               !isSPACE_A(*s)
+           );
+           break;
+       case NSPACEL:
+           REXEC_FBC_CSCAN_TAINT(
+               !isSPACE_LC_utf8((U8*)s),
+               !isSPACE_LC(*s)
+           );
+           break;
+       case DIGIT:
+           REXEC_FBC_CSCAN_PRELOAD(
+               LOAD_UTF8_CHARCLASS_DIGIT(),
+               swash_fetch(PL_utf8_digit,(U8*)s, utf8_target),
+               isDIGIT(*s)
+           );
+           break;
+       case DIGITA:
+           /* Don't need to worry about utf8, as it can match only a single
+            * byte invariant character */
+           REXEC_FBC_CLASS_SCAN( isDIGIT_A(*s));
+           break;
+       case DIGITL:
+           REXEC_FBC_CSCAN_TAINT(
+               isDIGIT_LC_utf8((U8*)s),
+               isDIGIT_LC(*s)
+           );
+           break;
+       case NDIGIT:
+           REXEC_FBC_CSCAN_PRELOAD(
+               LOAD_UTF8_CHARCLASS_DIGIT(),
+               !swash_fetch(PL_utf8_digit,(U8*)s, utf8_target),
+               !isDIGIT(*s)
+           );
+           break;
+       case NDIGITA:
+           REXEC_FBC_CSCAN(
+               !isDIGIT_A(*s),
+               !isDIGIT_A(*s)
+           );
+           break;
+       case NDIGITL:
+           REXEC_FBC_CSCAN_TAINT(
+               !isDIGIT_LC_utf8((U8*)s),
+               !isDIGIT_LC(*s)
+           );
+           break;
+       case LNBREAK:
+           REXEC_FBC_CSCAN(
+               is_LNBREAK_utf8_safe(s, strend),
+               is_LNBREAK_latin1_safe(s, strend)
+           );
+           break;
+       case VERTWS:
+           REXEC_FBC_CSCAN(
+               is_VERTWS_utf8_safe(s, strend),
+               is_VERTWS_latin1_safe(s, strend)
+           );
+           break;
+       case NVERTWS:
+           REXEC_FBC_CSCAN(
+               !is_VERTWS_utf8_safe(s, strend),
+               !is_VERTWS_latin1_safe(s, strend)
+           );
+           break;
+       case HORIZWS:
+           REXEC_FBC_CSCAN(
+               is_HORIZWS_utf8_safe(s, strend),
+               is_HORIZWS_latin1_safe(s, strend)
+           );
+           break;
+       case NHORIZWS:
+           REXEC_FBC_CSCAN(
+               !is_HORIZWS_utf8_safe(s, strend),
+               !is_HORIZWS_latin1_safe(s, strend)
+           );      
+           break;
+       case POSIXA:
+           /* Don't need to worry about utf8, as it can match only a single
+            * byte invariant character.  The flag in this node type is the
+            * class number to pass to _generic_isCC() to build a mask for
+            * searching in PL_charclass[] */
+           REXEC_FBC_CLASS_SCAN( _generic_isCC_A(*s, FLAGS(c)));
+           break;
+       case NPOSIXA:
+           REXEC_FBC_CSCAN(
+               !_generic_isCC_A(*s, FLAGS(c)),
+               !_generic_isCC_A(*s, FLAGS(c))
+           );
+           break;
+
+       case AHOCORASICKC:
+       case AHOCORASICK: 
+           {
+               DECL_TRIE_TYPE(c);
+                /* what trie are we using right now */
+               reg_ac_data *aho
+                   = (reg_ac_data*)progi->data->data[ ARG( c ) ];
+               reg_trie_data *trie
+                   = (reg_trie_data*)progi->data->data[ aho->trie ];
+               HV *widecharmap = MUTABLE_HV(progi->data->data[ aho->trie + 1 ]);
+
+               const char *last_start = strend - trie->minlen;
+#ifdef DEBUGGING
+               const char *real_start = s;
+#endif
+               STRLEN maxlen = trie->maxlen;
+               SV *sv_points;
+               U8 **points; /* map of where we were in the input string
+                               when reading a given char. For ASCII this
+                               is unnecessary overhead as the relationship
+                               is always 1:1, but for Unicode, especially
+                               case folded Unicode this is not true. */
+               U8 foldbuf[ UTF8_MAXBYTES_CASE + 1 ];
+               U8 *bitmap=NULL;
+
+
+                GET_RE_DEBUG_FLAGS_DECL;
+
+                /* We can't just allocate points here. We need to wrap it in
+                 * an SV so it gets freed properly if there is a croak while
+                 * running the match */
+                ENTER;
+               SAVETMPS;
+                sv_points=newSV(maxlen * sizeof(U8 *));
+                SvCUR_set(sv_points,
+                    maxlen * sizeof(U8 *));
+                SvPOK_on(sv_points);
+                sv_2mortal(sv_points);
+                points=(U8**)SvPV_nolen(sv_points );
+                if ( trie_type != trie_utf8_fold 
+                     && (trie->bitmap || OP(c)==AHOCORASICKC) ) 
+                {
+                    if (trie->bitmap) 
+                        bitmap=(U8*)trie->bitmap;
+                    else
+                        bitmap=(U8*)ANYOF_BITMAP(c);
+                }
+                /* this is the Aho-Corasick algorithm modified a touch
+                   to include special handling for long "unknown char" 
+                   sequences. The basic idea being that we use AC as long
+                   as we are dealing with a possible matching char, when
+                   we encounter an unknown char (and we have not encountered
+                   an accepting state) we scan forward until we find a legal 
+                   starting char. 
+                   AC matching is basically that of trie matching, except
+                   that when we encounter a failing transition, we fall back
+                   to the current states "fail state", and try the current char 
+                   again, a process we repeat until we reach the root state, 
+                   state 1, or a legal transition. If we fail on the root state 
+                   then we can either terminate if we have reached an accepting 
+                   state previously, or restart the entire process from the beginning 
+                   if we have not.
+
+                 */
+                while (s <= last_start) {
+                    const U32 uniflags = UTF8_ALLOW_DEFAULT;
+                    U8 *uc = (U8*)s;
+                    U16 charid = 0;
+                    U32 base = 1;
+                    U32 state = 1;
+                    UV uvc = 0;
+                    STRLEN len = 0;
+                    STRLEN foldlen = 0;
+                    U8 *uscan = (U8*)NULL;
+                    U8 *leftmost = NULL;
+#ifdef DEBUGGING                    
+                    U32 accepted_word= 0;
+#endif
+                    U32 pointpos = 0;
+
+                    while ( state && uc <= (U8*)strend ) {
+                        int failed=0;
+                        U32 word = aho->states[ state ].wordnum;
+
+                        if( state==1 ) {
+                            if ( bitmap ) {
+                                DEBUG_TRIE_EXECUTE_r(
+                                    if ( uc <= (U8*)last_start && !BITMAP_TEST(bitmap,*uc) ) {
+                                        dump_exec_pos( (char *)uc, c, strend, real_start, 
+                                            (char *)uc, utf8_target );
+                                        PerlIO_printf( Perl_debug_log,
+                                            " Scanning for legal start char...\n");
+                                    }
+                                );
+                               if (utf8_target) {
+                                   while ( uc <= (U8*)last_start && !BITMAP_TEST(bitmap,*uc) ) {
+                                       uc += UTF8SKIP(uc);
+                                   }
+                               } else {
+                                   while ( uc <= (U8*)last_start  && !BITMAP_TEST(bitmap,*uc) ) {
+                                       uc++;
+                                   }
+                               }
+                                s= (char *)uc;
+                            }
+                            if (uc >(U8*)last_start) break;
+                        }
+                                            
+                        if ( word ) {
+                            U8 *lpos= points[ (pointpos - trie->wordinfo[word].len) % maxlen ];
+                            if (!leftmost || lpos < leftmost) {
+                                DEBUG_r(accepted_word=word);
+                                leftmost= lpos;
+                            }
+                            if (base==0) break;
+                            
+                        }
+                        points[pointpos++ % maxlen]= uc;
+                        if (foldlen || uc < (U8*)strend) {
+                            REXEC_TRIE_READ_CHAR(trie_type, trie,
+                                             widecharmap, uc,
+                                            uscan, len, uvc, charid, foldlen,
+                                            foldbuf, uniflags);
+                            DEBUG_TRIE_EXECUTE_r({
+                                dump_exec_pos( (char *)uc, c, strend,
+                                            real_start, s, utf8_target);
+                                PerlIO_printf(Perl_debug_log,
+                                    " Charid:%3u CP:%4"UVxf" ",
+                                     charid, uvc);
+                            });
+                        }
+                        else {
+                            len = 0;
+                            charid = 0;
+                        }
+
+
+                        do {
+#ifdef DEBUGGING
+                            word = aho->states[ state ].wordnum;
+#endif
+                            base = aho->states[ state ].trans.base;
+
+                            DEBUG_TRIE_EXECUTE_r({
+                                if (failed) 
+                                    dump_exec_pos( (char *)uc, c, strend, real_start, 
+                                        s,   utf8_target );
+                                PerlIO_printf( Perl_debug_log,
+                                    "%sState: %4"UVxf", word=%"UVxf,
+                                    failed ? " Fail transition to " : "",
+                                    (UV)state, (UV)word);
+                            });
+                            if ( base ) {
+                                U32 tmp;
+                               I32 offset;
+                                if (charid &&
+                                    ( ((offset = base + charid
+                                       - 1 - trie->uniquecharcount)) >= 0)
+                                     && ((U32)offset < trie->lasttrans)
+                                     && trie->trans[offset].check == state
+                                     && (tmp=trie->trans[offset].next))
+                                {
+                                    DEBUG_TRIE_EXECUTE_r(
+                                        PerlIO_printf( Perl_debug_log," - legal\n"));
+                                    state = tmp;
+                                    break;
+                                }
+                                else {
+                                    DEBUG_TRIE_EXECUTE_r(
+                                        PerlIO_printf( Perl_debug_log," - fail\n"));
+                                    failed = 1;
+                                    state = aho->fail[state];
+                                }
+                            }
+                            else {
+                                /* we must be accepting here */
+                                DEBUG_TRIE_EXECUTE_r(
+                                        PerlIO_printf( Perl_debug_log," - accepting\n"));
+                                failed = 1;
+                                break;
+                            }
+                        } while(state);
+                        uc += len;
+                        if (failed) {
+                            if (leftmost)
+                                break;
+                            if (!state) state = 1;
+                        }
+                    }
+                    if ( aho->states[ state ].wordnum ) {
+                        U8 *lpos = points[ (pointpos - trie->wordinfo[aho->states[ state ].wordnum].len) % maxlen ];
+                        if (!leftmost || lpos < leftmost) {
+                            DEBUG_r(accepted_word=aho->states[ state ].wordnum);
+                            leftmost = lpos;
+                        }
+                    }
+                    if (leftmost) {
+                        s = (char*)leftmost;
+                        DEBUG_TRIE_EXECUTE_r({
+                            PerlIO_printf( 
+                                Perl_debug_log,"Matches word #%"UVxf" at position %"IVdf". Trying full pattern...\n",
+                                (UV)accepted_word, (IV)(s - real_start)
+                            );
+                        });
+                        if (!reginfo || regtry(reginfo, &s)) {
+                            FREETMPS;
+                           LEAVE;
+                            goto got_it;
+                        }
+                        s = HOPc(s,1);
+                        DEBUG_TRIE_EXECUTE_r({
+                            PerlIO_printf( Perl_debug_log,"Pattern failed. Looking for new start point...\n");
+                        });
+                    } else {
+                        DEBUG_TRIE_EXECUTE_r(
+                            PerlIO_printf( Perl_debug_log,"No match.\n"));
+                        break;
+                    }
+                }
+                FREETMPS;
+                LEAVE;
+           }
+           break;
+       default:
+           Perl_croak(aTHX_ "panic: unknown regstclass %d", (int)OP(c));
+           break;
+       }
+       return 0;
+      got_it:
+       return s;
+}
+
+
+/*
+ - regexec_flags - match a regexp against a string
+ */
+I32
+Perl_regexec_flags(pTHX_ REGEXP * const rx, char *stringarg, register char *strend,
+             char *strbeg, I32 minend, SV *sv, void *data, U32 flags)
+/* stringarg: the point in the string at which to begin matching */
+/* strend:    pointer to null at end of string */
+/* strbeg:    real beginning of string */
+/* minend:    end of match must be >= minend bytes after stringarg. */
+/* sv:        SV being matched: only used for utf8 flag, pos() etc; string
+ *            itself is accessed via the pointers above */
+/* data:      May be used for some additional optimizations.
+              Currently its only used, with a U32 cast, for transmitting
+              the ganch offset when doing a /g match. This will change */
+/* nosave:    For optimizations. */
+
+{
+    dVAR;
+    struct regexp *const prog = ReANY(rx);
+    /*register*/ char *s;
+    regnode *c;
+    /*register*/ char *startpos = stringarg;
+    I32 minlen;                /* must match at least this many chars */
+    I32 dontbother = 0;        /* how many characters not to try at end */
+    I32 end_shift = 0;                 /* Same for the end. */         /* CC */
+    I32 scream_pos = -1;               /* Internal iterator of scream. */
+    char *scream_olds = NULL;
+    const bool utf8_target = cBOOL(DO_UTF8(sv));
+    I32 multiline;
+    RXi_GET_DECL(prog,progi);
+    regmatch_info reginfo;  /* create some info to pass to regtry etc */
+    regexp_paren_pair *swap = NULL;
+    GET_RE_DEBUG_FLAGS_DECL;
+
+    PERL_ARGS_ASSERT_REGEXEC_FLAGS;
+    PERL_UNUSED_ARG(data);
+
+    /* Be paranoid... */
+    if (prog == NULL || startpos == NULL) {
+       Perl_croak(aTHX_ "NULL regexp parameter");
+       return 0;
+    }
+
+    multiline = prog->extflags & RXf_PMf_MULTILINE;
+    reginfo.prog = rx;  /* Yes, sorry that this is confusing.  */
+
+    RX_MATCH_UTF8_set(rx, utf8_target);
+    DEBUG_EXECUTE_r( 
+        debug_start_match(rx, utf8_target, startpos, strend,
+        "Matching");
+    );
+
+    minlen = prog->minlen;
+    
+    if (strend - startpos < (minlen+(prog->check_offset_min<0?prog->check_offset_min:0))) {
+        DEBUG_EXECUTE_r(PerlIO_printf(Perl_debug_log,
+                             "String too short [regexec_flags]...\n"));
+       goto phooey;
+    }
+
+    
+    /* Check validity of program. */
+    if (UCHARAT(progi->program) != REG_MAGIC) {
+       Perl_croak(aTHX_ "corrupted regexp program");
+    }
+
+    PL_reg_flags = 0;
+    PL_reg_state.re_state_eval_setup_done = FALSE;
+    PL_reg_maxiter = 0;
+
+    if (RX_UTF8(rx))
+       PL_reg_flags |= RF_utf8;
+
+    /* Mark beginning of line for ^ and lookbehind. */
+    reginfo.bol = startpos; /* XXX not used ??? */
+    PL_bostr  = strbeg;
+    reginfo.sv = sv;
+
+    /* Mark end of line for $ (and such) */
+    PL_regeol = strend;
+
+    /* see how far we have to get to not match where we matched before */
+    reginfo.till = startpos+minend;
+
+    /* If there is a "must appear" string, look for it. */
+    s = startpos;
+
+    if (prog->extflags & RXf_GPOS_SEEN) { /* Need to set reginfo->ganch */
+       MAGIC *mg;
+       if (flags & REXEC_IGNOREPOS){   /* Means: check only at start */
+           reginfo.ganch = startpos + prog->gofs;
+           DEBUG_GPOS_r(PerlIO_printf(Perl_debug_log,
+             "GPOS IGNOREPOS: reginfo.ganch = startpos + %"UVxf"\n",(UV)prog->gofs));
+       } else if (sv && SvTYPE(sv) >= SVt_PVMG
+                 && SvMAGIC(sv)
+                 && (mg = mg_find(sv, PERL_MAGIC_regex_global))
+                 && mg->mg_len >= 0) {
+           reginfo.ganch = strbeg + mg->mg_len;        /* Defined pos() */
+           DEBUG_GPOS_r(PerlIO_printf(Perl_debug_log,
+               "GPOS MAGIC: reginfo.ganch = strbeg + %"IVdf"\n",(IV)mg->mg_len));
+
+           if (prog->extflags & RXf_ANCH_GPOS) {
+               if (s > reginfo.ganch)
+                   goto phooey;
+               s = reginfo.ganch - prog->gofs;
+               DEBUG_GPOS_r(PerlIO_printf(Perl_debug_log,
+                    "GPOS ANCH_GPOS: s = ganch - %"UVxf"\n",(UV)prog->gofs));
+               if (s < strbeg)
+                   goto phooey;
+           }
+       }
+       else if (data) {
+           reginfo.ganch = strbeg + PTR2UV(data);
+            DEBUG_GPOS_r(PerlIO_printf(Perl_debug_log,
+                "GPOS DATA: reginfo.ganch= strbeg + %"UVxf"\n",PTR2UV(data)));
+
+       } else {                                /* pos() not defined */
+           reginfo.ganch = strbeg;
+            DEBUG_GPOS_r(PerlIO_printf(Perl_debug_log,
+                "GPOS: reginfo.ganch = strbeg\n"));
+       }
+    }
+    if (PL_curpm && (PM_GETRE(PL_curpm) == rx)) {
+        /* We have to be careful. If the previous successful match
+           was from this regex we don't want a subsequent partially
+           successful match to clobber the old results.
+           So when we detect this possibility we add a swap buffer
+           to the re, and switch the buffer each match. If we fail
+           we switch it back, otherwise we leave it swapped.
+        */
+        swap = prog->offs;
+        /* do we need a save destructor here for eval dies? */
+        Newxz(prog->offs, (prog->nparens + 1), regexp_paren_pair);
+       DEBUG_BUFFERS_r(PerlIO_printf(Perl_debug_log,
+           "rex=0x%"UVxf" saving  offs: orig=0x%"UVxf" new=0x%"UVxf"\n",
+           PTR2UV(prog),
+           PTR2UV(swap),
+           PTR2UV(prog->offs)
+       ));
+    }
+    if (!(flags & REXEC_CHECKED) && (prog->check_substr != NULL || prog->check_utf8 != NULL)) {
+       re_scream_pos_data d;
+
+       d.scream_olds = &scream_olds;
+       d.scream_pos = &scream_pos;
+       s = re_intuit_start(rx, sv, s, strend, flags, &d);
+       if (!s) {
+           DEBUG_EXECUTE_r(PerlIO_printf(Perl_debug_log, "Not present...\n"));
+           goto phooey;        /* not present */
+       }
+    }
+
+
+
+    /* Simplest case:  anchored match need be tried only once. */
+    /*  [unless only anchor is BOL and multiline is set] */
+    if (prog->extflags & (RXf_ANCH & ~RXf_ANCH_GPOS)) {
+       if (s == startpos && regtry(&reginfo, &startpos))
+           goto got_it;
+       else if (multiline || (prog->intflags & PREGf_IMPLICIT)
+                || (prog->extflags & RXf_ANCH_MBOL)) /* XXXX SBOL? */
+       {
+           char *end;
+
+           if (minlen)
+               dontbother = minlen - 1;
+           end = HOP3c(strend, -dontbother, strbeg) - 1;
+           /* for multiline we only have to try after newlines */
+           if (prog->check_substr || prog->check_utf8) {
+                /* because of the goto we can not easily reuse the macros for bifurcating the
+                   unicode/non-unicode match modes here like we do elsewhere - demerphq */
+                if (utf8_target) {
+                    if (s == startpos)
+                        goto after_try_utf8;
+                    while (1) {
+                        if (regtry(&reginfo, &s)) {
+                            goto got_it;
+                        }
+                      after_try_utf8:
+                        if (s > end) {
+                            goto phooey;
+                        }
+                        if (prog->extflags & RXf_USE_INTUIT) {
+                            s = re_intuit_start(rx, sv, s + UTF8SKIP(s), strend, flags, NULL);
+                            if (!s) {
+                                goto phooey;
+                            }
+                        }
+                        else {
+                            s += UTF8SKIP(s);
+                        }
+                    }
+                } /* end search for check string in unicode */
+                else {
+                    if (s == startpos) {
+                        goto after_try_latin;
+                    }
+                    while (1) {
+                        if (regtry(&reginfo, &s)) {
+                            goto got_it;
+                        }
+                      after_try_latin:
+                        if (s > end) {
+                            goto phooey;
+                        }
+                        if (prog->extflags & RXf_USE_INTUIT) {
+                            s = re_intuit_start(rx, sv, s + 1, strend, flags, NULL);
+                            if (!s) {
+                                goto phooey;
+                            }
+                        }
+                        else {
+                            s++;
+                        }
+                    }
+                } /* end search for check string in latin*/
+           } /* end search for check string */
+           else { /* search for newline */
+               if (s > startpos) {
+                    /*XXX: The s-- is almost definitely wrong here under unicode - demeprhq*/
+                   s--;
+               }
+               /* We can use a more efficient search as newlines are the same in unicode as they are in latin */
+               while (s <= end) { /* note it could be possible to match at the end of the string */
+                   if (*s++ == '\n') { /* don't need PL_utf8skip here */
+                       if (regtry(&reginfo, &s))
+                           goto got_it;
+                   }
+               }
+           } /* end search for newline */
+       } /* end anchored/multiline check string search */
+       goto phooey;
+    } else if (RXf_GPOS_CHECK == (prog->extflags & RXf_GPOS_CHECK)) 
+    {
+        /* the warning about reginfo.ganch being used without initialization
+           is bogus -- we set it above, when prog->extflags & RXf_GPOS_SEEN 
+           and we only enter this block when the same bit is set. */
+        char *tmp_s = reginfo.ganch - prog->gofs;
+
+       if (tmp_s >= strbeg && regtry(&reginfo, &tmp_s))
+           goto got_it;
+       goto phooey;
+    }
+
+    /* Messy cases:  unanchored match. */
+    if ((prog->anchored_substr || prog->anchored_utf8) && prog->intflags & PREGf_SKIP) {
+       /* we have /x+whatever/ */
+       /* it must be a one character string (XXXX Except UTF_PATTERN?) */
+       char ch;
+#ifdef DEBUGGING
+       int did_match = 0;
+#endif
+       if (utf8_target) {
+            if (! prog->anchored_utf8) {
+                to_utf8_substr(prog);
+            }
+            ch = SvPVX_const(prog->anchored_utf8)[0];
+           REXEC_FBC_SCAN(
+               if (*s == ch) {
+                   DEBUG_EXECUTE_r( did_match = 1 );
+                   if (regtry(&reginfo, &s)) goto got_it;
+                   s += UTF8SKIP(s);
+                   while (s < strend && *s == ch)
+                       s += UTF8SKIP(s);
+               }
+           );
+
+       }
+       else {
+            if (! prog->anchored_substr) {
+                if (! to_byte_substr(prog)) {
+                    NON_UTF8_TARGET_BUT_UTF8_REQUIRED(phooey);
+                }
+            }
+            ch = SvPVX_const(prog->anchored_substr)[0];
+           REXEC_FBC_SCAN(
+               if (*s == ch) {
+                   DEBUG_EXECUTE_r( did_match = 1 );
+                   if (regtry(&reginfo, &s)) goto got_it;
+                   s++;
+                   while (s < strend && *s == ch)
+                       s++;
+               }
+           );
+       }
+       DEBUG_EXECUTE_r(if (!did_match)
+               PerlIO_printf(Perl_debug_log,
+                                  "Did not find anchored character...\n")
+               );
+    }
+    else if (prog->anchored_substr != NULL
+             || prog->anchored_utf8 != NULL
+             || ((prog->float_substr != NULL || prog->float_utf8 != NULL)
+                 && prog->float_max_offset < strend - s)) {
+       SV *must;
+       I32 back_max;
+       I32 back_min;
+       char *last;
+       char *last1;            /* Last position checked before */
+#ifdef DEBUGGING
+       int did_match = 0;
+#endif
+       if (prog->anchored_substr || prog->anchored_utf8) {
+           if (utf8_target) {
+                if (! prog->anchored_utf8) {
+                    to_utf8_substr(prog);
+                }
+                must = prog->anchored_utf8;
+            }
+            else {
+                if (! prog->anchored_substr) {
+                    if (! to_byte_substr(prog)) {
+                        NON_UTF8_TARGET_BUT_UTF8_REQUIRED(phooey);
+                    }
+                }
+                must = prog->anchored_substr;
+            }
+           back_max = back_min = prog->anchored_offset;
+       } else {
+           if (utf8_target) {
+                if (! prog->float_utf8) {
+                    to_utf8_substr(prog);
+                }
+                must = prog->float_utf8;
+            }
+            else {
+                if (! prog->float_substr) {
+                    if (! to_byte_substr(prog)) {
+                        NON_UTF8_TARGET_BUT_UTF8_REQUIRED(phooey);
+                    }
+                }
+                must = prog->float_substr;
+            }
+           back_max = prog->float_max_offset;
+           back_min = prog->float_min_offset;
+       }
+           
+        if (back_min<0) {
+           last = strend;
+       } else {
+            last = HOP3c(strend,       /* Cannot start after this */
+                 -(I32)(CHR_SVLEN(must)
+                        - (SvTAIL(must) != 0) + back_min), strbeg);
+        }
+       if (s > PL_bostr)
+           last1 = HOPc(s, -1);
+       else
+           last1 = s - 1;      /* bogus */
+
+       /* XXXX check_substr already used to find "s", can optimize if
+          check_substr==must. */
+       scream_pos = -1;
+       dontbother = end_shift;
+       strend = HOPc(strend, -dontbother);
+       while ( (s <= last) &&
+               (s = fbm_instr((unsigned char*)HOP3(s, back_min, (back_min<0 ? strbeg : strend)),
+                                 (unsigned char*)strend, must,
+                                 multiline ? FBMrf_MULTILINE : 0)) ) {
+           DEBUG_EXECUTE_r( did_match = 1 );
+           if (HOPc(s, -back_max) > last1) {
+               last1 = HOPc(s, -back_min);
+               s = HOPc(s, -back_max);
+           }
+           else {
+               char * const t = (last1 >= PL_bostr) ? HOPc(last1, 1) : last1 + 1;
+
+               last1 = HOPc(s, -back_min);
+               s = t;
+           }
+           if (utf8_target) {
+               while (s <= last1) {
+                   if (regtry(&reginfo, &s))
+                       goto got_it;
+                    if (s >= last1) {
+                        s++; /* to break out of outer loop */
+                        break;
+                    }
+                    s += UTF8SKIP(s);
+               }
+           }
+           else {
+               while (s <= last1) {
+                   if (regtry(&reginfo, &s))
+                       goto got_it;
+                   s++;
+               }
+           }
+       }
+       DEBUG_EXECUTE_r(if (!did_match) {
+            RE_PV_QUOTED_DECL(quoted, utf8_target, PERL_DEBUG_PAD_ZERO(0),
+                SvPVX_const(must), RE_SV_DUMPLEN(must), 30);
+            PerlIO_printf(Perl_debug_log, "Did not find %s substr %s%s...\n",
+                             ((must == prog->anchored_substr || must == prog->anchored_utf8)
+                              ? "anchored" : "floating"),
+                quoted, RE_SV_TAIL(must));
+        });                
+       goto phooey;
+    }
+    else if ( (c = progi->regstclass) ) {
+       if (minlen) {
+           const OPCODE op = OP(progi->regstclass);
+           /* don't bother with what can't match */
+           if (PL_regkind[op] != EXACT && op != CANY && PL_regkind[op] != TRIE)
+               strend = HOPc(strend, -(minlen - 1));
+       }
+       DEBUG_EXECUTE_r({
+           SV * const prop = sv_newmortal();
+           regprop(prog, prop, c);
+           {
+               RE_PV_QUOTED_DECL(quoted,utf8_target,PERL_DEBUG_PAD_ZERO(1),
+                   s,strend-s,60);
+               PerlIO_printf(Perl_debug_log,
+                   "Matching stclass %.*s against %s (%d bytes)\n",
+                   (int)SvCUR(prop), SvPVX_const(prop),
+                    quoted, (int)(strend - s));
+           }
+       });
+        if (find_byclass(prog, c, s, strend, &reginfo))
+           goto got_it;
+       DEBUG_EXECUTE_r(PerlIO_printf(Perl_debug_log, "Contradicts stclass... [regexec_flags]\n"));
+    }
+    else {
+       dontbother = 0;
+       if (prog->float_substr != NULL || prog->float_utf8 != NULL) {
+           /* Trim the end. */
+           char *last= NULL;
+           SV* float_real;
+           STRLEN len;
+           const char *little;
+
+           if (utf8_target) {
+                if (! prog->float_utf8) {
+                    to_utf8_substr(prog);
+                }
+                float_real = prog->float_utf8;
+            }
+            else {
+                if (! prog->float_substr) {
+                    if (! to_byte_substr(prog)) {
+                        NON_UTF8_TARGET_BUT_UTF8_REQUIRED(phooey);
+                    }
+                }
+                float_real = prog->float_substr;
+            }
+
+            little = SvPV_const(float_real, len);
+           if (SvTAIL(float_real)) {
+                    /* This means that float_real contains an artificial \n on
+                     * the end due to the presence of something like this:
+                     * /foo$/ where we can match both "foo" and "foo\n" at the
+                     * end of the string.  So we have to compare the end of the
+                     * string first against the float_real without the \n and
+                     * then against the full float_real with the string.  We
+                     * have to watch out for cases where the string might be
+                     * smaller than the float_real or the float_real without
+                     * the \n. */
+                   char *checkpos= strend - len;
+                   DEBUG_OPTIMISE_r(
+                       PerlIO_printf(Perl_debug_log,
+                           "%sChecking for float_real.%s\n",
+                           PL_colors[4], PL_colors[5]));
+                   if (checkpos + 1 < strbeg) {
+                        /* can't match, even if we remove the trailing \n
+                         * string is too short to match */
+                       DEBUG_EXECUTE_r(
+                           PerlIO_printf(Perl_debug_log,
+                               "%sString shorter than required trailing substring, cannot match.%s\n",
+                               PL_colors[4], PL_colors[5]));
+                       goto phooey;
+                   } else if (memEQ(checkpos + 1, little, len - 1)) {
+                        /* can match, the end of the string matches without the
+                         * "\n" */
+                       last = checkpos + 1;
+                   } else if (checkpos < strbeg) {
+                        /* cant match, string is too short when the "\n" is
+                         * included */
+                       DEBUG_EXECUTE_r(
+                           PerlIO_printf(Perl_debug_log,
+                               "%sString does not contain required trailing substring, cannot match.%s\n",
+                               PL_colors[4], PL_colors[5]));
+                       goto phooey;
+                   } else if (!multiline) {
+                        /* non multiline match, so compare with the "\n" at the
+                         * end of the string */
+                       if (memEQ(checkpos, little, len)) {
+                           last= checkpos;
+                       } else {
+                           DEBUG_EXECUTE_r(
+                               PerlIO_printf(Perl_debug_log,
+                                   "%sString does not contain required trailing substring, cannot match.%s\n",
+                                   PL_colors[4], PL_colors[5]));
+                           goto phooey;
+                       }
+                   } else {
+                        /* multiline match, so we have to search for a place
+                         * where the full string is located */
+                       goto find_last;
+                   }
+           } else {
+                 find_last:
+                   if (len)
+                       last = rninstr(s, strend, little, little + len);
+                   else
+                       last = strend;  /* matching "$" */
+           }
+           if (!last) {
+                /* at one point this block contained a comment which was
+                 * probably incorrect, which said that this was a "should not
+                 * happen" case.  Even if it was true when it was written I am
+                 * pretty sure it is not anymore, so I have removed the comment
+                 * and replaced it with this one. Yves */
+               DEBUG_EXECUTE_r(
+                   PerlIO_printf(Perl_debug_log,
+                       "String does not contain required substring, cannot match.\n"
+                   ));
+               goto phooey;
+           }
+           dontbother = strend - last + prog->float_min_offset;
+       }
+       if (minlen && (dontbother < minlen))
+           dontbother = minlen - 1;
+       strend -= dontbother;              /* this one's always in bytes! */
+       /* We don't know much -- general case. */
+       if (utf8_target) {
+           for (;;) {
+               if (regtry(&reginfo, &s))
+                   goto got_it;
+               if (s >= strend)
+                   break;
+               s += UTF8SKIP(s);
+           };
+       }
+       else {
+           do {
+               if (regtry(&reginfo, &s))
+                   goto got_it;
+           } while (s++ < strend);
+       }
+    }
+
+    /* Failure. */
+    goto phooey;
+
+got_it:
+    DEBUG_BUFFERS_r(
+       if (swap)
+           PerlIO_printf(Perl_debug_log,
+               "rex=0x%"UVxf" freeing offs: 0x%"UVxf"\n",
+               PTR2UV(prog),
+               PTR2UV(swap)
+           );
+    );
+    Safefree(swap);
+    RX_MATCH_TAINTED_set(rx, PL_reg_flags & RF_tainted);
+
+    if (PL_reg_state.re_state_eval_setup_done)
+       restore_pos(aTHX_ prog);
+    if (RXp_PAREN_NAMES(prog)) 
+        (void)hv_iterinit(RXp_PAREN_NAMES(prog));
+
+    /* make sure $`, $&, $', and $digit will work later */
+    if ( !(flags & REXEC_NOT_FIRST) ) {
+       if (flags & REXEC_COPY_STR) {
+#ifdef PERL_OLD_COPY_ON_WRITE
+           if ((SvIsCOW(sv)
+                || (SvFLAGS(sv) & CAN_COW_MASK) == CAN_COW_FLAGS)) {
+               if (DEBUG_C_TEST) {
+                   PerlIO_printf(Perl_debug_log,
+                                 "Copy on write: regexp capture, type %d\n",
+                                 (int) SvTYPE(sv));
+               }
+                RX_MATCH_COPY_FREE(rx);
+               prog->saved_copy = sv_setsv_cow(prog->saved_copy, sv);
+               prog->subbeg = (char *)SvPVX_const(prog->saved_copy);
+               assert (SvPOKp(prog->saved_copy));
+                prog->sublen  = PL_regeol - strbeg;
+                prog->suboffset = 0;
+                prog->subcoffset = 0;
+           } else
+#endif
+           {
+                I32 min = 0;
+                I32 max = PL_regeol - strbeg;
+                I32 sublen;
+
+                if (    (flags & REXEC_COPY_SKIP_POST)
+                    && !(RX_EXTFLAGS(rx) & RXf_PMf_KEEPCOPY) /* //p */
+                    && !(PL_sawampersand & SAWAMPERSAND_RIGHT)
+                ) { /* don't copy $' part of string */
+                    U32 n = 0;
+                    max = -1;
+                    /* calculate the right-most part of the string covered
+                     * by a capture. Due to look-ahead, this may be to
+                     * the right of $&, so we have to scan all captures */
+                    while (n <= prog->lastparen) {
+                        if (prog->offs[n].end > max)
+                            max = prog->offs[n].end;
+                        n++;
+                    }
+                    if (max == -1)
+                        max = (PL_sawampersand & SAWAMPERSAND_LEFT)
+                                ? prog->offs[0].start
+                                : 0;
+                    assert(max >= 0 && max <= PL_regeol - strbeg);
+                }
+
+                if (    (flags & REXEC_COPY_SKIP_PRE)
+                    && !(RX_EXTFLAGS(rx) & RXf_PMf_KEEPCOPY) /* //p */
+                    && !(PL_sawampersand & SAWAMPERSAND_LEFT)
+                ) { /* don't copy $` part of string */
+                    U32 n = 0;
+                    min = max;
+                    /* calculate the left-most part of the string covered
+                     * by a capture. Due to look-behind, this may be to
+                     * the left of $&, so we have to scan all captures */
+                    while (min && n <= prog->lastparen) {
+                        if (   prog->offs[n].start != -1
+                            && prog->offs[n].start < min)
+                        {
+                            min = prog->offs[n].start;
+                        }
+                        n++;
+                    }
+                    if ((PL_sawampersand & SAWAMPERSAND_RIGHT)
+                        && min >  prog->offs[0].end
+                    )
+                        min = prog->offs[0].end;
+
+                }
+
+                assert(min >= 0 && min <= max && min <= PL_regeol - strbeg);
+                sublen = max - min;
+
+                if (RX_MATCH_COPIED(rx)) {
+                    if (sublen > prog->sublen)
+                        prog->subbeg =
+                                (char*)saferealloc(prog->subbeg, sublen+1);
+                }
+                else
+                    prog->subbeg = (char*)safemalloc(sublen+1);
+                Copy(strbeg + min, prog->subbeg, sublen, char);
+                prog->subbeg[sublen] = '\0';
+                prog->suboffset = min;
+                prog->sublen = sublen;
+                RX_MATCH_COPIED_on(rx);
+           }
+            prog->subcoffset = prog->suboffset;
+            if (prog->suboffset && utf8_target) {
+                /* Convert byte offset to chars.
+                 * XXX ideally should only compute this if @-/@+
+                 * has been seen, a la PL_sawampersand ??? */
+
+                /* If there's a direct correspondence between the
+                 * string which we're matching and the original SV,
+                 * then we can use the utf8 len cache associated with
+                 * the SV. In particular, it means that under //g,
+                 * sv_pos_b2u() will use the previously cached
+                 * position to speed up working out the new length of
+                 * subcoffset, rather than counting from the start of
+                 * the string each time. This stops
+                 *   $x = "\x{100}" x 1E6; 1 while $x =~ /(.)/g;
+                 * from going quadratic */
+                if (SvPOKp(sv) && SvPVX(sv) == strbeg)
+                    sv_pos_b2u(sv, &(prog->subcoffset));
+                else
+                    prog->subcoffset = utf8_length((U8*)strbeg,
+                                        (U8*)(strbeg+prog->suboffset));
+            }
+       }
+       else {
+            RX_MATCH_COPY_FREE(rx);
+           prog->subbeg = strbeg;
+           prog->suboffset = 0;
+           prog->subcoffset = 0;
+           prog->sublen = PL_regeol - strbeg;  /* strend may have been modified */
+       }
+    }
+
+    return 1;
+
+phooey:
+    DEBUG_EXECUTE_r(PerlIO_printf(Perl_debug_log, "%sMatch failed%s\n",
+                         PL_colors[4], PL_colors[5]));
+    if (PL_reg_state.re_state_eval_setup_done)
+       restore_pos(aTHX_ prog);
+    if (swap) {
+        /* we failed :-( roll it back */
+       DEBUG_BUFFERS_r(PerlIO_printf(Perl_debug_log,
+           "rex=0x%"UVxf" rolling back offs: freeing=0x%"UVxf" restoring=0x%"UVxf"\n",
+           PTR2UV(prog),
+           PTR2UV(prog->offs),
+           PTR2UV(swap)
+       ));
+        Safefree(prog->offs);
+        prog->offs = swap;
+    }
+    return 0;
+}
+
+
+/* Set which rex is pointed to by PL_reg_state, handling ref counting.
+ * Do inc before dec, in case old and new rex are the same */
+#define SET_reg_curpm(Re2) \
+    if (PL_reg_state.re_state_eval_setup_done) {    \
+       (void)ReREFCNT_inc(Re2);                    \
+       ReREFCNT_dec(PM_GETRE(PL_reg_curpm));       \
+       PM_SETRE((PL_reg_curpm), (Re2));            \
+    }
+
+
+/*
+ - regtry - try match at specific point
+ */
+STATIC I32                     /* 0 failure, 1 success */
+S_regtry(pTHX_ regmatch_info *reginfo, char **startposp)
+{
+    dVAR;
+    CHECKPOINT lastcp;
+    REGEXP *const rx = reginfo->prog;
+    regexp *const prog = ReANY(rx);
+    I32 result;
+    RXi_GET_DECL(prog,progi);
+    GET_RE_DEBUG_FLAGS_DECL;
+
+    PERL_ARGS_ASSERT_REGTRY;
+
+    reginfo->cutpoint=NULL;
+
+    if ((prog->extflags & RXf_EVAL_SEEN)
+       && !PL_reg_state.re_state_eval_setup_done)
+    {
+       MAGIC *mg;
+
+       PL_reg_state.re_state_eval_setup_done = TRUE;
+       if (reginfo->sv) {
+           /* Make $_ available to executed code. */
+           if (reginfo->sv != DEFSV) {
+               SAVE_DEFSV;
+               DEFSV_set(reginfo->sv);
+           }
+       
+           if (!(SvTYPE(reginfo->sv) >= SVt_PVMG && SvMAGIC(reginfo->sv)
+                 && (mg = mg_find(reginfo->sv, PERL_MAGIC_regex_global)))) {
+               /* prepare for quick setting of pos */
+#ifdef PERL_OLD_COPY_ON_WRITE
+               if (SvIsCOW(reginfo->sv))
+                   sv_force_normal_flags(reginfo->sv, 0);
+#endif
+               mg = sv_magicext(reginfo->sv, NULL, PERL_MAGIC_regex_global,
+                                &PL_vtbl_mglob, NULL, 0);
+               mg->mg_len = -1;
+           }
+           PL_reg_magic    = mg;
+           PL_reg_oldpos   = mg->mg_len;
+           SAVEDESTRUCTOR_X(restore_pos, prog);
+        }
+        if (!PL_reg_curpm) {
+           Newxz(PL_reg_curpm, 1, PMOP);
+#ifdef USE_ITHREADS
+            {
+               SV* const repointer = &PL_sv_undef;
+                /* this regexp is also owned by the new PL_reg_curpm, which
+                  will try to free it.  */
+                av_push(PL_regex_padav, repointer);
+                PL_reg_curpm->op_pmoffset = av_len(PL_regex_padav);
+                PL_regex_pad = AvARRAY(PL_regex_padav);
+            }
+#endif      
+        }
+       SET_reg_curpm(rx);
+       PL_reg_oldcurpm = PL_curpm;
+       PL_curpm = PL_reg_curpm;
+       if (RXp_MATCH_COPIED(prog)) {
+           /*  Here is a serious problem: we cannot rewrite subbeg,
+               since it may be needed if this match fails.  Thus
+               $` inside (?{}) could fail... */
+           PL_reg_oldsaved = prog->subbeg;
+           PL_reg_oldsavedlen = prog->sublen;
+           PL_reg_oldsavedoffset = prog->suboffset;
+           PL_reg_oldsavedcoffset = prog->suboffset;
+#ifdef PERL_OLD_COPY_ON_WRITE
+           PL_nrs = prog->saved_copy;
+#endif
+           RXp_MATCH_COPIED_off(prog);
+       }
+       else
+           PL_reg_oldsaved = NULL;
+       prog->subbeg = PL_bostr;
+       prog->suboffset = 0;
+       prog->subcoffset = 0;
+       prog->sublen = PL_regeol - PL_bostr; /* strend may have been modified */
+    }
+#ifdef DEBUGGING
+    PL_reg_starttry = *startposp;
+#endif
+    prog->offs[0].start = *startposp - PL_bostr;
+    prog->lastparen = 0;
+    prog->lastcloseparen = 0;
+    PL_regsize = 0;
+
+    /* XXXX What this code is doing here?!!!  There should be no need
+       to do this again and again, prog->lastparen should take care of
+       this!  --ilya*/
+
+    /* Tests pat.t#187 and split.t#{13,14} seem to depend on this code.
+     * Actually, the code in regcppop() (which Ilya may be meaning by
+     * prog->lastparen), is not needed at all by the test suite
+     * (op/regexp, op/pat, op/split), but that code is needed otherwise
+     * this erroneously leaves $1 defined: "1" =~ /^(?:(\d)x)?\d$/
+     * Meanwhile, this code *is* needed for the
+     * above-mentioned test suite tests to succeed.  The common theme
+     * on those tests seems to be returning null fields from matches.
+     * --jhi updated by dapm */
+#if 1
+    if (prog->nparens) {
+       regexp_paren_pair *pp = prog->offs;
+       I32 i;
+       for (i = prog->nparens; i > (I32)prog->lastparen; i--) {
+           ++pp;
+           pp->start = -1;
+           pp->end = -1;
+       }
+    }
+#endif
+    REGCP_SET(lastcp);
+    result = regmatch(reginfo, *startposp, progi->program + 1);
+    if (result != -1) {
+       prog->offs[0].end = result;
+       return 1;
+    }
+    if (reginfo->cutpoint)
+        *startposp= reginfo->cutpoint;
+    REGCP_UNWIND(lastcp);
+    return 0;
+}
+
+
+#define sayYES goto yes
+#define sayNO goto no
+#define sayNO_SILENT goto no_silent
+
+/* we dont use STMT_START/END here because it leads to 
+   "unreachable code" warnings, which are bogus, but distracting. */
+#define CACHEsayNO \
+    if (ST.cache_mask) \
+       PL_reg_poscache[ST.cache_offset] |= ST.cache_mask; \
+    sayNO
+
+/* this is used to determine how far from the left messages like
+   'failed...' are printed. It should be set such that messages 
+   are inline with the regop output that created them.
+*/
+#define REPORT_CODE_OFF 32
+
+
+#define CHRTEST_UNINIT -1001 /* c1/c2 haven't been calculated yet */
+#define CHRTEST_VOID   -1000 /* the c1/c2 "next char" test should be skipped */
+#define CHRTEST_NOT_A_CP_1 -999
+#define CHRTEST_NOT_A_CP_2 -998
+
+#define SLAB_FIRST(s) (&(s)->states[0])
+#define SLAB_LAST(s)  (&(s)->states[PERL_REGMATCH_SLAB_SLOTS-1])
+
+/* grab a new slab and return the first slot in it */
+
+STATIC regmatch_state *
+S_push_slab(pTHX)
+{
+#if PERL_VERSION < 9 && !defined(PERL_CORE)
+    dMY_CXT;
+#endif
+    regmatch_slab *s = PL_regmatch_slab->next;
+    if (!s) {
+       Newx(s, 1, regmatch_slab);
+       s->prev = PL_regmatch_slab;
+       s->next = NULL;
+       PL_regmatch_slab->next = s;
+    }
+    PL_regmatch_slab = s;
+    return SLAB_FIRST(s);
+}
+
+
+/* push a new state then goto it */
+
+#define PUSH_STATE_GOTO(state, node, input) \
+    pushinput = input; \
+    scan = node; \
+    st->resume_state = state; \
+    goto push_state;
+
+/* push a new state with success backtracking, then goto it */
+
+#define PUSH_YES_STATE_GOTO(state, node, input) \
+    pushinput = input; \
+    scan = node; \
+    st->resume_state = state; \
+    goto push_yes_state;
+
+
+
+
+/*
+
+regmatch() - main matching routine
+
+This is basically one big switch statement in a loop. We execute an op,
+set 'next' to point the next op, and continue. If we come to a point which
+we may need to backtrack to on failure such as (A|B|C), we push a
+backtrack state onto the backtrack stack. On failure, we pop the top
+state, and re-enter the loop at the state indicated. If there are no more
+states to pop, we return failure.
+
+Sometimes we also need to backtrack on success; for example /A+/, where
+after successfully matching one A, we need to go back and try to
+match another one; similarly for lookahead assertions: if the assertion
+completes successfully, we backtrack to the state just before the assertion
+and then carry on.  In these cases, the pushed state is marked as
+'backtrack on success too'. This marking is in fact done by a chain of
+pointers, each pointing to the previous 'yes' state. On success, we pop to
+the nearest yes state, discarding any intermediate failure-only states.
+Sometimes a yes state is pushed just to force some cleanup code to be
+called at the end of a successful match or submatch; e.g. (??{$re}) uses
+it to free the inner regex.
+
+Note that failure backtracking rewinds the cursor position, while
+success backtracking leaves it alone.
+
+A pattern is complete when the END op is executed, while a subpattern
+such as (?=foo) is complete when the SUCCESS op is executed. Both of these
+ops trigger the "pop to last yes state if any, otherwise return true"
+behaviour.
+
+A common convention in this function is to use A and B to refer to the two
+subpatterns (or to the first nodes thereof) in patterns like /A*B/: so A is
+the subpattern to be matched possibly multiple times, while B is the entire
+rest of the pattern. Variable and state names reflect this convention.
+
+The states in the main switch are the union of ops and failure/success of
+substates associated with with that op.  For example, IFMATCH is the op
+that does lookahead assertions /(?=A)B/ and so the IFMATCH state means
+'execute IFMATCH'; while IFMATCH_A is a state saying that we have just
+successfully matched A and IFMATCH_A_fail is a state saying that we have
+just failed to match A. Resume states always come in pairs. The backtrack
+state we push is marked as 'IFMATCH_A', but when that is popped, we resume
+at IFMATCH_A or IFMATCH_A_fail, depending on whether we are backtracking
+on success or failure.
+
+The struct that holds a backtracking state is actually a big union, with
+one variant for each major type of op. The variable st points to the
+top-most backtrack struct. To make the code clearer, within each
+block of code we #define ST to alias the relevant union.
+
+Here's a concrete example of a (vastly oversimplified) IFMATCH
+implementation:
+
+    switch (state) {
+    ....
+
+#define ST st->u.ifmatch
+
+    case IFMATCH: // we are executing the IFMATCH op, (?=A)B
+       ST.foo = ...; // some state we wish to save
+       ...
+       // push a yes backtrack state with a resume value of
+       // IFMATCH_A/IFMATCH_A_fail, then continue execution at the
+       // first node of A:
+       PUSH_YES_STATE_GOTO(IFMATCH_A, A, newinput);
+       // NOTREACHED
+
+    case IFMATCH_A: // we have successfully executed A; now continue with B
+       next = B;
+       bar = ST.foo; // do something with the preserved value
+       break;
+
+    case IFMATCH_A_fail: // A failed, so the assertion failed
+       ...;   // do some housekeeping, then ...
+       sayNO; // propagate the failure
+
+#undef ST
+
+    ...
+    }
+
+For any old-timers reading this who are familiar with the old recursive
+approach, the code above is equivalent to:
+
+    case IFMATCH: // we are executing the IFMATCH op, (?=A)B
+    {
+       int foo = ...
+       ...
+       if (regmatch(A)) {
+           next = B;
+           bar = foo;
+           break;
+       }
+       ...;   // do some housekeeping, then ...
+       sayNO; // propagate the failure
+    }
+
+The topmost backtrack state, pointed to by st, is usually free. If you
+want to claim it, populate any ST.foo fields in it with values you wish to
+save, then do one of
+
+       PUSH_STATE_GOTO(resume_state, node, newinput);
+       PUSH_YES_STATE_GOTO(resume_state, node, newinput);
+
+which sets that backtrack state's resume value to 'resume_state', pushes a
+new free entry to the top of the backtrack stack, then goes to 'node'.
+On backtracking, the free slot is popped, and the saved state becomes the
+new free state. An ST.foo field in this new top state can be temporarily
+accessed to retrieve values, but once the main loop is re-entered, it
+becomes available for reuse.
+
+Note that the depth of the backtrack stack constantly increases during the
+left-to-right execution of the pattern, rather than going up and down with
+the pattern nesting. For example the stack is at its maximum at Z at the
+end of the pattern, rather than at X in the following:
+
+    /(((X)+)+)+....(Y)+....Z/
+
+The only exceptions to this are lookahead/behind assertions and the cut,
+(?>A), which pop all the backtrack states associated with A before
+continuing.
+Backtrack state structs are allocated in slabs of about 4K in size.
+PL_regmatch_state and st always point to the currently active state,
+and PL_regmatch_slab points to the slab currently containing
+PL_regmatch_state.  The first time regmatch() is called, the first slab is
+allocated, and is never freed until interpreter destruction. When the slab
+is full, a new one is allocated and chained to the end. At exit from
+regmatch(), slabs allocated since entry are freed.
+
+*/
+
+#define DEBUG_STATE_pp(pp)                                 \
+    DEBUG_STATE_r({                                        \
+       DUMP_EXEC_POS(locinput, scan, utf8_target);                 \
+       PerlIO_printf(Perl_debug_log,                       \
+           "    %*s"pp" %s%s%s%s%s\n",                     \
+           depth*2, "",                                    \
+           PL_reg_name[st->resume_state],                     \
+           ((st==yes_state||st==mark_state) ? "[" : ""),   \
+           ((st==yes_state) ? "Y" : ""),                   \
+           ((st==mark_state) ? "M" : ""),                  \
+           ((st==yes_state||st==mark_state) ? "]" : "")    \
+       );                                                  \
+    });
+
+
+#define REG_NODE_NUM(x) ((x) ? (int)((x)-prog) : -1)
+
+#ifdef DEBUGGING
+
+STATIC void
+S_debug_start_match(pTHX_ const REGEXP *prog, const bool utf8_target,
+    const char *start, const char *end, const char *blurb)
+{
+    const bool utf8_pat = RX_UTF8(prog) ? 1 : 0;
+
+    PERL_ARGS_ASSERT_DEBUG_START_MATCH;
+
+    if (!PL_colorset)   
+            reginitcolors();    
+    {
+        RE_PV_QUOTED_DECL(s0, utf8_pat, PERL_DEBUG_PAD_ZERO(0), 
+            RX_PRECOMP_const(prog), RX_PRELEN(prog), 60);   
+        
+        RE_PV_QUOTED_DECL(s1, utf8_target, PERL_DEBUG_PAD_ZERO(1),
+            start, end - start, 60); 
+        
+        PerlIO_printf(Perl_debug_log, 
+            "%s%s REx%s %s against %s\n", 
+                      PL_colors[4], blurb, PL_colors[5], s0, s1); 
+        
+        if (utf8_target||utf8_pat)
+            PerlIO_printf(Perl_debug_log, "UTF-8 %s%s%s...\n",
+                utf8_pat ? "pattern" : "",
+                utf8_pat && utf8_target ? " and " : "",
+                utf8_target ? "string" : ""
+            ); 
+    }
+}
+
+STATIC void
+S_dump_exec_pos(pTHX_ const char *locinput, 
+                      const regnode *scan, 
+                      const char *loc_regeol, 
+                      const char *loc_bostr, 
+                      const char *loc_reg_starttry,
+                      const bool utf8_target)
+{
+    const int docolor = *PL_colors[0] || *PL_colors[2] || *PL_colors[4];
+    const int taill = (docolor ? 10 : 7); /* 3 chars for "> <" */
+    int l = (loc_regeol - locinput) > taill ? taill : (loc_regeol - locinput);
+    /* The part of the string before starttry has one color
+       (pref0_len chars), between starttry and current
+       position another one (pref_len - pref0_len chars),
+       after the current position the third one.
+       We assume that pref0_len <= pref_len, otherwise we
+       decrease pref0_len.  */
+    int pref_len = (locinput - loc_bostr) > (5 + taill) - l
+       ? (5 + taill) - l : locinput - loc_bostr;
+    int pref0_len;
+
+    PERL_ARGS_ASSERT_DUMP_EXEC_POS;
+
+    while (utf8_target && UTF8_IS_CONTINUATION(*(U8*)(locinput - pref_len)))
+       pref_len++;
+    pref0_len = pref_len  - (locinput - loc_reg_starttry);
+    if (l + pref_len < (5 + taill) && l < loc_regeol - locinput)
+       l = ( loc_regeol - locinput > (5 + taill) - pref_len
+             ? (5 + taill) - pref_len : loc_regeol - locinput);
+    while (utf8_target && UTF8_IS_CONTINUATION(*(U8*)(locinput + l)))
+       l--;
+    if (pref0_len < 0)
+       pref0_len = 0;
+    if (pref0_len > pref_len)
+       pref0_len = pref_len;
+    {
+       const int is_uni = (utf8_target && OP(scan) != CANY) ? 1 : 0;
+
+       RE_PV_COLOR_DECL(s0,len0,is_uni,PERL_DEBUG_PAD(0),
+           (locinput - pref_len),pref0_len, 60, 4, 5);
+       
+       RE_PV_COLOR_DECL(s1,len1,is_uni,PERL_DEBUG_PAD(1),
+                   (locinput - pref_len + pref0_len),
+                   pref_len - pref0_len, 60, 2, 3);
+       
+       RE_PV_COLOR_DECL(s2,len2,is_uni,PERL_DEBUG_PAD(2),
+                   locinput, loc_regeol - locinput, 10, 0, 1);
+
+       const STRLEN tlen=len0+len1+len2;
+       PerlIO_printf(Perl_debug_log,
+                   "%4"IVdf" <%.*s%.*s%s%.*s>%*s|",
+                   (IV)(locinput - loc_bostr),
+                   len0, s0,
+                   len1, s1,
+                   (docolor ? "" : "> <"),
+                   len2, s2,
+                   (int)(tlen > 19 ? 0 :  19 - tlen),
+                   "");
+    }
+}
+
+#endif
+
+/* reg_check_named_buff_matched()
+ * Checks to see if a named buffer has matched. The data array of 
+ * buffer numbers corresponding to the buffer is expected to reside
+ * in the regexp->data->data array in the slot stored in the ARG() of
+ * node involved. Note that this routine doesn't actually care about the
+ * name, that information is not preserved from compilation to execution.
+ * Returns the index of the leftmost defined buffer with the given name
+ * or 0 if non of the buffers matched.
+ */
+STATIC I32
+S_reg_check_named_buff_matched(pTHX_ const regexp *rex, const regnode *scan)
+{
+    I32 n;
+    RXi_GET_DECL(rex,rexi);
+    SV *sv_dat= MUTABLE_SV(rexi->data->data[ ARG( scan ) ]);
+    I32 *nums=(I32*)SvPVX(sv_dat);
+
+    PERL_ARGS_ASSERT_REG_CHECK_NAMED_BUFF_MATCHED;
+
+    for ( n=0; n<SvIVX(sv_dat); n++ ) {
+        if ((I32)rex->lastparen >= nums[n] &&
+            rex->offs[nums[n]].end != -1)
+        {
+            return nums[n];
+        }
+    }
+    return 0;
+}
+
+
+/* free all slabs above current one  - called during LEAVE_SCOPE */
+
+STATIC void
+S_clear_backtrack_stack(pTHX_ void *p)
+{
+    regmatch_slab *s = PL_regmatch_slab->next;
+    PERL_UNUSED_ARG(p);
+
+    if (!s)
+       return;
+    PL_regmatch_slab->next = NULL;
+    while (s) {
+       regmatch_slab * const osl = s;
+       s = s->next;
+       Safefree(osl);
+    }
+}
+static bool
+S_setup_EXACTISH_ST_c1_c2(pTHX_ const regnode * const text_node, int *c1p, U8* c1_utf8, int *c2p, U8* c2_utf8)
+{
+    /* This function determines if there are one or two characters that match
+     * the first character of the passed-in EXACTish node <text_node>, and if
+     * so, returns them in the passed-in pointers.
+     *
+     * If it determines that no possible character in the target string can
+     * match, it returns FALSE; otherwise TRUE.  (The FALSE situation occurs if
+     * the first character in <text_node> requires UTF-8 to represent, and the
+     * target string isn't in UTF-8.)
+     *
+     * If there are more than two characters that could match the beginning of
+     * <text_node>, or if more context is required to determine a match or not,
+     * it sets both *<c1p> and *<c2p> to CHRTEST_VOID.
+     *
+     * The motiviation behind this function is to allow the caller to set up
+     * tight loops for matching.  If <text_node> is of type EXACT, there is
+     * only one possible character that can match its first character, and so
+     * the situation is quite simple.  But things get much more complicated if
+     * folding is involved.  It may be that the first character of an EXACTFish
+     * node doesn't participate in any possible fold, e.g., punctuation, so it
+     * can be matched only by itself.  The vast majority of characters that are
+     * in folds match just two things, their lower and upper-case equivalents.
+     * But not all are like that; some have multiple possible matches, or match
+     * sequences of more than one character.  This function sorts all that out.
+     *
+     * Consider the patterns A*B or A*?B where A and B are arbitrary.  In a
+     * loop of trying to match A*, we know we can't exit where the thing
+     * following it isn't a B.  And something can't be a B unless it is the
+     * beginning of B.  By putting a quick test for that beginning in a tight
+     * loop, we can rule out things that can't possibly be B without having to
+     * break out of the loop, thus avoiding work.  Similarly, if A is a single
+     * character, we can make a tight loop matching A*, using the outputs of
+     * this function.
+     *
+     * If the target string to match isn't in UTF-8, and there aren't
+     * complications which require CHRTEST_VOID, *<c1p> and *<c2p> are set to
+     * the one or two possible octets (which are characters in this situation)
+     * that can match.  In all cases, if there is only one character that can
+     * match, *<c1p> and *<c2p> will be identical.
+     *
+     * If the target string is in UTF-8, the buffers pointed to by <c1_utf8>
+     * and <c2_utf8> will contain the one or two UTF-8 sequences of bytes that
+     * can match the beginning of <text_node>.  They should be declared with at
+     * least length UTF8_MAXBYTES+1.  (If the target string isn't in UTF-8, it is
+     * undefined what these contain.)  If one or both of the buffers are
+     * invariant under UTF-8, *<c1p>, and *<c2p> will also be set to the
+     * corresponding invariant.  If variant, the corresponding *<c1p> and/or
+     * *<c2p> will be set to a negative number(s) that shouldn't match any code
+     * point (unless inappropriately coerced to unsigned).   *<c1p> will equal
+     * *<c2p> if and only if <c1_utf8> and <c2_utf8> are the same. */
+
+    const bool utf8_target = PL_reg_match_utf8;
+
+    UV c1 = CHRTEST_NOT_A_CP_1;
+    UV c2 = CHRTEST_NOT_A_CP_2;
+    bool use_chrtest_void = FALSE;
+
+    /* Used when we have both utf8 input and utf8 output, to avoid converting
+     * to/from code points */
+    bool utf8_has_been_setup = FALSE;
+
+    dVAR;
+
+    U8 *pat = (U8*)STRING(text_node);
+
+    if (OP(text_node) == EXACT) {
+
+        /* In an exact node, only one thing can be matched, that first
+         * character.  If both the pat and the target are UTF-8, we can just
+         * copy the input to the output, avoiding finding the code point of
+         * that character */
+        if (! UTF_PATTERN) {
+            c2 = c1 = *pat;
+        }
+        else if (utf8_target) {
+            Copy(pat, c1_utf8, UTF8SKIP(pat), U8);
+            Copy(pat, c2_utf8, UTF8SKIP(pat), U8);
+            utf8_has_been_setup = TRUE;
+        }
+        else {
+            c2 = c1 = valid_utf8_to_uvchr(pat, NULL);
+        }
+    }
+    else /* an EXACTFish node */
+         if ((UTF_PATTERN
+                    && is_MULTI_CHAR_FOLD_utf8_safe(pat,
+                                                    pat + STR_LEN(text_node)))
+             || (! UTF_PATTERN
+                    && is_MULTI_CHAR_FOLD_latin1_safe(pat,
+                                                    pat + STR_LEN(text_node))))
+    {
+        /* Multi-character folds require more context to sort out.  Also
+         * PL_utf8_foldclosures used below doesn't handle them, so have to be
+         * handled outside this routine */
+        use_chrtest_void = TRUE;
+    }
+    else { /* an EXACTFish node which doesn't begin with a multi-char fold */
+        c1 = (UTF_PATTERN) ? valid_utf8_to_uvchr(pat, NULL) : *pat;
+        if (c1 > 256) {
+            /* Load the folds hash, if not already done */
+            SV** listp;
+            if (! PL_utf8_foldclosures) {
+                if (! PL_utf8_tofold) {
+                    U8 dummy[UTF8_MAXBYTES+1];
+
+                    /* Force loading this by folding an above-Latin1 char */
+                    to_utf8_fold((U8*) HYPHEN_UTF8, dummy, NULL);
+                    assert(PL_utf8_tofold); /* Verify that worked */
+                }
+                PL_utf8_foldclosures = _swash_inversion_hash(PL_utf8_tofold);
+            }
+
+            /* The fold closures data structure is a hash with the keys being
+             * the UTF-8 of every character that is folded to, like 'k', and
+             * the values each an array of all code points that fold to its
+             * key.  e.g. [ 'k', 'K', KELVIN_SIGN ].  Multi-character folds are
+             * not included */
+            if ((! (listp = hv_fetch(PL_utf8_foldclosures,
+                                     (char *) pat,
+                                     UTF8SKIP(pat),
+                                     FALSE))))
+            {
+                /* Not found in the hash, therefore there are no folds
+                 * containing it, so there is only a single character that
+                 * could match */
+                c2 = c1;
+            }
+            else {  /* Does participate in folds */
+                AV* list = (AV*) *listp;
+                if (av_len(list) != 1) {
+
+                    /* If there aren't exactly two folds to this, it is outside
+                     * the scope of this function */
+                    use_chrtest_void = TRUE;
+                }
+                else {  /* There are two.  Get them */
+                    SV** c_p = av_fetch(list, 0, FALSE);
+                    if (c_p == NULL) {
+                        Perl_croak(aTHX_ "panic: invalid PL_utf8_foldclosures structure");
+                    }
+                    c1 = SvUV(*c_p);
+
+                    c_p = av_fetch(list, 1, FALSE);
+                    if (c_p == NULL) {
+                        Perl_croak(aTHX_ "panic: invalid PL_utf8_foldclosures structure");
+                    }
+                    c2 = SvUV(*c_p);
+
+                    /* Folds that cross the 255/256 boundary are forbidden if
+                     * EXACTFL, or EXACTFA and one is ASCIII.  Since the
+                     * pattern character is above 256, and its only other match
+                     * is below 256, the only legal match will be to itself.
+                     * We have thrown away the original, so have to compute
+                     * which is the one above 255 */
+                    if ((c1 < 256) != (c2 < 256)) {
+                        if (OP(text_node) == EXACTFL
+                            || (OP(text_node) == EXACTFA
+                                && (isASCII(c1) || isASCII(c2))))
+                        {
+                            if (c1 < 256) {
+                                c1 = c2;
+                            }
+                            else {
+                                c2 = c1;
+                            }
+                        }
+                    }
+                }
+            }
+        }
+        else /* Here, c1 is < 255 */
+             if (utf8_target
+                 && HAS_NONLATIN1_FOLD_CLOSURE(c1)
+                 && OP(text_node) != EXACTFL
+                 && (OP(text_node) != EXACTFA || ! isASCII(c1)))
+        {
+            /* Here, there could be something above Latin1 in the target which
+             * folds to this character in the pattern.  All such cases except
+             * LATIN SMALL LETTER Y WITH DIAERESIS have more than two characters
+             * involved in their folds, so are outside the scope of this
+             * function */
+            if (UNLIKELY(c1 == LATIN_SMALL_LETTER_Y_WITH_DIAERESIS)) {
+                c2 = LATIN_CAPITAL_LETTER_Y_WITH_DIAERESIS;
+            }
+            else {
+                use_chrtest_void = TRUE;
+            }
+        }
+        else { /* Here nothing above Latin1 can fold to the pattern character */
+            switch (OP(text_node)) {
+
+                case EXACTFL:   /* /l rules */
+                    c2 = PL_fold_locale[c1];
+                    break;
+
+                case EXACTF:
+                    if (! utf8_target) {    /* /d rules */
+                        c2 = PL_fold[c1];
+                        break;
+                    }
+                    /* FALLTHROUGH */
+                    /* /u rules for all these.  This happens to work for
+                     * EXACTFA as nothing in Latin1 folds to ASCII */
+                case EXACTFA:
+                case EXACTFU_TRICKYFOLD:
+                case EXACTFU_SS:
+                case EXACTFU:
+                    c2 = PL_fold_latin1[c1];
+                    break;
+
+               default:
+                    Perl_croak(aTHX_ "panic: Unexpected op %u", OP(text_node));
+                    assert(0); /* NOTREACHED */
+            }
+        }
+    }
+
+    /* Here have figured things out.  Set up the returns */
+    if (use_chrtest_void) {
+        *c2p = *c1p = CHRTEST_VOID;
+    }
+    else if (utf8_target) {
+        if (! utf8_has_been_setup) {    /* Don't have the utf8; must get it */
+            uvchr_to_utf8(c1_utf8, c1);
+            uvchr_to_utf8(c2_utf8, c2);
+        }
+
+        /* Invariants are stored in both the utf8 and byte outputs; Use
+         * negative numbers otherwise for the byte ones.  Make sure that the
+         * byte ones are the same iff the utf8 ones are the same */
+        *c1p = (UTF8_IS_INVARIANT(*c1_utf8)) ? *c1_utf8 : CHRTEST_NOT_A_CP_1;
+        *c2p = (UTF8_IS_INVARIANT(*c2_utf8))
+                ? *c2_utf8
+                : (c1 == c2)
+                  ? CHRTEST_NOT_A_CP_1
+                  : CHRTEST_NOT_A_CP_2;
+    }
+    else if (c1 > 255) {
+       if (c2 > 255) {  /* both possibilities are above what a non-utf8 string
+                           can represent */
+           return FALSE;
+       }
+
+       *c1p = *c2p = c2;    /* c2 is the only representable value */
+    }
+    else {  /* c1 is representable; see about c2 */
+       *c1p = c1;
+       *c2p = (c2 < 256) ? c2 : c1;
+    }
+
+    return TRUE;
+}
+
+/* returns -1 on failure, $+[0] on success */
+STATIC I32
+S_regmatch(pTHX_ regmatch_info *reginfo, char *startpos, regnode *prog)
+{
+#if PERL_VERSION < 9 && !defined(PERL_CORE)
+    dMY_CXT;
+#endif
+    dVAR;
+    const bool utf8_target = PL_reg_match_utf8;
+    const U32 uniflags = UTF8_ALLOW_DEFAULT;
+    REGEXP *rex_sv = reginfo->prog;
+    regexp *rex = ReANY(rex_sv);
+    RXi_GET_DECL(rex,rexi);
+    I32        oldsave;
+    /* the current state. This is a cached copy of PL_regmatch_state */
+    regmatch_state *st;
+    /* cache heavy used fields of st in registers */
+    regnode *scan;
+    regnode *next;
+    U32 n = 0; /* general value; init to avoid compiler warning */
+    I32 ln = 0; /* len or last;  init to avoid compiler warning */
+    char *locinput = startpos;
+    char *pushinput; /* where to continue after a PUSH */
+    I32 nextchr;   /* is always set to UCHARAT(locinput) */
+
+    bool result = 0;       /* return value of S_regmatch */
+    int depth = 0;         /* depth of backtrack stack */
+    U32 nochange_depth = 0; /* depth of GOSUB recursion with nochange */
+    const U32 max_nochange_depth =
+        (3 * rex->nparens > MAX_RECURSE_EVAL_NOCHANGE_DEPTH) ?
+        3 * rex->nparens : MAX_RECURSE_EVAL_NOCHANGE_DEPTH;
+    regmatch_state *yes_state = NULL; /* state to pop to on success of
+                                                           subpattern */
+    /* mark_state piggy backs on the yes_state logic so that when we unwind 
+       the stack on success we can update the mark_state as we go */
+    regmatch_state *mark_state = NULL; /* last mark state we have seen */
+    regmatch_state *cur_eval = NULL; /* most recent EVAL_AB state */
+    struct regmatch_state  *cur_curlyx = NULL; /* most recent curlyx */
+    U32 state_num;
+    bool no_final = 0;      /* prevent failure from backtracking? */
+    bool do_cutgroup = 0;   /* no_final only until next branch/trie entry */
+    char *startpoint = locinput;
+    SV *popmark = NULL;     /* are we looking for a mark? */
+    SV *sv_commit = NULL;   /* last mark name seen in failure */
+    SV *sv_yes_mark = NULL; /* last mark name we have seen 
+                               during a successful match */
+    U32 lastopen = 0;       /* last open we saw */
+    bool has_cutgroup = RX_HAS_CUTGROUP(rex) ? 1 : 0;   
+    SV* const oreplsv = GvSV(PL_replgv);
+    /* these three flags are set by various ops to signal information to
+     * the very next op. They have a useful lifetime of exactly one loop
+     * iteration, and are not preserved or restored by state pushes/pops
+     */
+    bool sw = 0;           /* the condition value in (?(cond)a|b) */
+    bool minmod = 0;       /* the next "{n,m}" is a "{n,m}?" */
+    int logical = 0;       /* the following EVAL is:
+                               0: (?{...})
+                               1: (?(?{...})X|Y)
+                               2: (??{...})
+                              or the following IFMATCH/UNLESSM is:
+                               false: plain (?=foo)
+                               true:  used as a condition: (?(?=foo))
+                           */
+    PAD* last_pad = NULL;
+    dMULTICALL;
+    I32 gimme = G_SCALAR;
+    CV *caller_cv = NULL;      /* who called us */
+    CV *last_pushed_cv = NULL; /* most recently called (?{}) CV */
+    CHECKPOINT runops_cp;      /* savestack position before executing EVAL */
+
+#ifdef DEBUGGING
+    GET_RE_DEBUG_FLAGS_DECL;
+#endif
+
+    /* shut up 'may be used uninitialized' compiler warnings for dMULTICALL */
+    multicall_oldcatch = 0;
+    multicall_cv = NULL;
+    cx = NULL;
+    PERL_UNUSED_VAR(multicall_cop);
+    PERL_UNUSED_VAR(newsp);
+
+
+    PERL_ARGS_ASSERT_REGMATCH;
+
+    DEBUG_OPTIMISE_r( DEBUG_EXECUTE_r({
+           PerlIO_printf(Perl_debug_log,"regmatch start\n");
+    }));
+    /* on first ever call to regmatch, allocate first slab */
+    if (!PL_regmatch_slab) {
+       Newx(PL_regmatch_slab, 1, regmatch_slab);
+       PL_regmatch_slab->prev = NULL;
+       PL_regmatch_slab->next = NULL;
+       PL_regmatch_state = SLAB_FIRST(PL_regmatch_slab);
+    }
+
+    oldsave = PL_savestack_ix;
+    SAVEDESTRUCTOR_X(S_clear_backtrack_stack, NULL);
+    SAVEVPTR(PL_regmatch_slab);
+    SAVEVPTR(PL_regmatch_state);
+
+    /* grab next free state slot */
+    st = ++PL_regmatch_state;
+    if (st >  SLAB_LAST(PL_regmatch_slab))
+       st = PL_regmatch_state = S_push_slab(aTHX);
+
+    /* Note that nextchr is a byte even in UTF */
+    SET_nextchr;
+    scan = prog;
+    while (scan != NULL) {
+
+        DEBUG_EXECUTE_r( {
+           SV * const prop = sv_newmortal();
+           regnode *rnext=regnext(scan);
+           DUMP_EXEC_POS( locinput, scan, utf8_target );
+           regprop(rex, prop, scan);
+            
+           PerlIO_printf(Perl_debug_log,
+                   "%3"IVdf":%*s%s(%"IVdf")\n",
+                   (IV)(scan - rexi->program), depth*2, "",
+                   SvPVX_const(prop),
+                   (PL_regkind[OP(scan)] == END || !rnext) ? 
+                       0 : (IV)(rnext - rexi->program));
+       });
+
+       next = scan + NEXT_OFF(scan);
+       if (next == scan)
+           next = NULL;
+       state_num = OP(scan);
+
+      reenter_switch:
+
+        SET_nextchr;
+        assert(nextchr < 256 && (nextchr >= 0 || nextchr == NEXTCHR_EOS));
+
+       switch (state_num) {
+       case BOL: /*  /^../  */
+           if (locinput == PL_bostr)
+           {
+               /* reginfo->till = reginfo->bol; */
+               break;
+           }
+           sayNO;
+
+       case MBOL: /*  /^../m  */
+           if (locinput == PL_bostr ||
+               (!NEXTCHR_IS_EOS && locinput[-1] == '\n'))
+           {
+               break;
+           }
+           sayNO;
+
+       case SBOL: /*  /^../s  */
+           if (locinput == PL_bostr)
+               break;
+           sayNO;
+
+       case GPOS: /*  \G  */
+           if (locinput == reginfo->ganch)
+               break;
+           sayNO;
+
+       case KEEPS: /*   \K  */
+           /* update the startpoint */
+           st->u.keeper.val = rex->offs[0].start;
+           rex->offs[0].start = locinput - PL_bostr;
+           PUSH_STATE_GOTO(KEEPS_next, next, locinput);
+           assert(0); /*NOTREACHED*/
+       case KEEPS_next_fail:
+           /* rollback the start point change */
+           rex->offs[0].start = st->u.keeper.val;
+           sayNO_SILENT;
+           assert(0); /*NOTREACHED*/
+
+       case EOL: /* /..$/  */
+               goto seol;
+
+       case MEOL: /* /..$/m  */
+           if (!NEXTCHR_IS_EOS && nextchr != '\n')
+               sayNO;
+           break;
+
+       case SEOL: /* /..$/s  */
+         seol:
+           if (!NEXTCHR_IS_EOS && nextchr != '\n')
+               sayNO;
+           if (PL_regeol - locinput > 1)
+               sayNO;
+           break;
+
+       case EOS: /*  \z  */
+           if (!NEXTCHR_IS_EOS)
+               sayNO;
+           break;
+
+       case SANY: /*  /./s  */
+           if (NEXTCHR_IS_EOS)
+               sayNO;
+            goto increment_locinput;
+
+       case CANY: /*  \C  */
+           if (NEXTCHR_IS_EOS)
+               sayNO;
+           locinput++;
+           break;
+
+       case REG_ANY: /*  /./  */
+           if ((NEXTCHR_IS_EOS) || nextchr == '\n')
+               sayNO;
+            goto increment_locinput;
+
+
+#undef  ST
+#define ST st->u.trie
+        case TRIEC: /* (ab|cd) with known charclass */
+            /* In this case the charclass data is available inline so
+               we can fail fast without a lot of extra overhead. 
+             */
+            if(!NEXTCHR_IS_EOS && !ANYOF_BITMAP_TEST(scan, nextchr)) {
+                DEBUG_EXECUTE_r(
+                    PerlIO_printf(Perl_debug_log,
+                              "%*s  %sfailed to match trie start class...%s\n",
+                              REPORT_CODE_OFF+depth*2, "", PL_colors[4], PL_colors[5])
+                );
+                sayNO_SILENT;
+                assert(0); /* NOTREACHED */
+            }
+            /* FALL THROUGH */
+       case TRIE:  /* (ab|cd)  */
+           /* the basic plan of execution of the trie is:
+            * At the beginning, run though all the states, and
+            * find the longest-matching word. Also remember the position
+            * of the shortest matching word. For example, this pattern:
+            *    1  2 3 4    5
+            *    ab|a|x|abcd|abc
+            * when matched against the string "abcde", will generate
+            * accept states for all words except 3, with the longest
+            * matching word being 4, and the shortest being 2 (with
+            * the position being after char 1 of the string).
+            *
+            * Then for each matching word, in word order (i.e. 1,2,4,5),
+            * we run the remainder of the pattern; on each try setting
+            * the current position to the character following the word,
+            * returning to try the next word on failure.
+            *
+            * We avoid having to build a list of words at runtime by
+            * using a compile-time structure, wordinfo[].prev, which
+            * gives, for each word, the previous accepting word (if any).
+            * In the case above it would contain the mappings 1->2, 2->0,
+            * 3->0, 4->5, 5->1.  We can use this table to generate, from
+            * the longest word (4 above), a list of all words, by
+            * following the list of prev pointers; this gives us the
+            * unordered list 4,5,1,2. Then given the current word we have
+            * just tried, we can go through the list and find the
+            * next-biggest word to try (so if we just failed on word 2,
+            * the next in the list is 4).
+            *
+            * Since at runtime we don't record the matching position in
+            * the string for each word, we have to work that out for
+            * each word we're about to process. The wordinfo table holds
+            * the character length of each word; given that we recorded
+            * at the start: the position of the shortest word and its
+            * length in chars, we just need to move the pointer the
+            * difference between the two char lengths. Depending on
+            * Unicode status and folding, that's cheap or expensive.
+            *
+            * This algorithm is optimised for the case where are only a
+            * small number of accept states, i.e. 0,1, or maybe 2.
+            * With lots of accepts states, and having to try all of them,
+            * it becomes quadratic on number of accept states to find all
+            * the next words.
+            */
+
+           {
+                /* what type of TRIE am I? (utf8 makes this contextual) */
+                DECL_TRIE_TYPE(scan);
+
+                /* what trie are we using right now */
+               reg_trie_data * const trie
+                   = (reg_trie_data*)rexi->data->data[ ARG( scan ) ];
+               HV * widecharmap = MUTABLE_HV(rexi->data->data[ ARG( scan ) + 1 ]);
+                U32 state = trie->startstate;
+
+                if (   trie->bitmap
+                    && (NEXTCHR_IS_EOS || !TRIE_BITMAP_TEST(trie, nextchr)))
+                {
+                   if (trie->states[ state ].wordnum) {
+                        DEBUG_EXECUTE_r(
+                            PerlIO_printf(Perl_debug_log,
+                                         "%*s  %smatched empty string...%s\n",
+                                         REPORT_CODE_OFF+depth*2, "", PL_colors[4], PL_colors[5])
+                        );
+                       if (!trie->jump)
+                           break;
+                   } else {
+                       DEBUG_EXECUTE_r(
+                            PerlIO_printf(Perl_debug_log,
+                                         "%*s  %sfailed to match trie start class...%s\n",
+                                         REPORT_CODE_OFF+depth*2, "", PL_colors[4], PL_colors[5])
+                        );
+                       sayNO_SILENT;
+                  }
+                }
+
+            { 
+               U8 *uc = ( U8* )locinput;
+
+               STRLEN len = 0;
+               STRLEN foldlen = 0;
+               U8 *uscan = (U8*)NULL;
+               U8 foldbuf[ UTF8_MAXBYTES_CASE + 1 ];
+               U32 charcount = 0; /* how many input chars we have matched */
+               U32 accepted = 0; /* have we seen any accepting states? */
+
+               ST.jump = trie->jump;
+               ST.me = scan;
+               ST.firstpos = NULL;
+               ST.longfold = FALSE; /* char longer if folded => it's harder */
+               ST.nextword = 0;
+
+               /* fully traverse the TRIE; note the position of the
+                  shortest accept state and the wordnum of the longest
+                  accept state */
+
+               while ( state && uc <= (U8*)PL_regeol ) {
+                    U32 base = trie->states[ state ].trans.base;
+                    UV uvc = 0;
+                    U16 charid = 0;
+                   U16 wordnum;
+                    wordnum = trie->states[ state ].wordnum;
+
+                   if (wordnum) { /* it's an accept state */
+                       if (!accepted) {
+                           accepted = 1;
+                           /* record first match position */
+                           if (ST.longfold) {
+                               ST.firstpos = (U8*)locinput;
+                               ST.firstchars = 0;
+                           }
+                           else {
+                               ST.firstpos = uc;
+                               ST.firstchars = charcount;
+                           }
+                       }
+                       if (!ST.nextword || wordnum < ST.nextword)
+                           ST.nextword = wordnum;
+                       ST.topword = wordnum;
+                   }
+
+                   DEBUG_TRIE_EXECUTE_r({
+                               DUMP_EXEC_POS( (char *)uc, scan, utf8_target );
+                               PerlIO_printf( Perl_debug_log,
+                                   "%*s  %sState: %4"UVxf" Accepted: %c ",
+                                   2+depth * 2, "", PL_colors[4],
+                                   (UV)state, (accepted ? 'Y' : 'N'));
+                   });
+
+                   /* read a char and goto next state */
+                   if ( base && (foldlen || uc < (U8*)PL_regeol)) {
+                       I32 offset;
+                       REXEC_TRIE_READ_CHAR(trie_type, trie, widecharmap, uc,
+                                            uscan, len, uvc, charid, foldlen,
+                                            foldbuf, uniflags);
+                       charcount++;
+                       if (foldlen>0)
+                           ST.longfold = TRUE;
+                       if (charid &&
+                            ( ((offset =
+                             base + charid - 1 - trie->uniquecharcount)) >= 0)
+
+                            && ((U32)offset < trie->lasttrans)
+                            && trie->trans[offset].check == state)
+                       {
+                           state = trie->trans[offset].next;
+                       }
+                       else {
+                           state = 0;
+                       }
+                       uc += len;
+
+                   }
+                   else {
+                       state = 0;
+                   }
+                   DEBUG_TRIE_EXECUTE_r(
+                       PerlIO_printf( Perl_debug_log,
+                           "Charid:%3x CP:%4"UVxf" After State: %4"UVxf"%s\n",
+                           charid, uvc, (UV)state, PL_colors[5] );
+                   );
+               }
+               if (!accepted)
+                  sayNO;
+
+               /* calculate total number of accept states */
+               {
+                   U16 w = ST.topword;
+                   accepted = 0;
+                   while (w) {
+                       w = trie->wordinfo[w].prev;
+                       accepted++;
+                   }
+                   ST.accepted = accepted;
+               }
+
+               DEBUG_EXECUTE_r(
+                   PerlIO_printf( Perl_debug_log,
+                       "%*s  %sgot %"IVdf" possible matches%s\n",
+                       REPORT_CODE_OFF + depth * 2, "",
+                       PL_colors[4], (IV)ST.accepted, PL_colors[5] );
+               );
+               goto trie_first_try; /* jump into the fail handler */
+           }}
+           assert(0); /* NOTREACHED */
+
+       case TRIE_next_fail: /* we failed - try next alternative */
+        {
+            U8 *uc;
+            if ( ST.jump) {
+                REGCP_UNWIND(ST.cp);
+                UNWIND_PAREN(ST.lastparen, ST.lastcloseparen);
+           }
+           if (!--ST.accepted) {
+               DEBUG_EXECUTE_r({
+                   PerlIO_printf( Perl_debug_log,
+                       "%*s  %sTRIE failed...%s\n",
+                       REPORT_CODE_OFF+depth*2, "", 
+                       PL_colors[4],
+                       PL_colors[5] );
+               });
+               sayNO_SILENT;
+           }
+           {
+               /* Find next-highest word to process.  Note that this code
+                * is O(N^2) per trie run (O(N) per branch), so keep tight */
+               U16 min = 0;
+               U16 word;
+               U16 const nextword = ST.nextword;
+               reg_trie_wordinfo * const wordinfo
+                   = ((reg_trie_data*)rexi->data->data[ARG(ST.me)])->wordinfo;
+               for (word=ST.topword; word; word=wordinfo[word].prev) {
+                   if (word > nextword && (!min || word < min))
+                       min = word;
+               }
+               ST.nextword = min;
+           }
+
+          trie_first_try:
+            if (do_cutgroup) {
+                do_cutgroup = 0;
+                no_final = 0;
+            }
+
+            if ( ST.jump) {
+                ST.lastparen = rex->lastparen;
+                ST.lastcloseparen = rex->lastcloseparen;
+               REGCP_SET(ST.cp);
+            }
+
+           /* find start char of end of current word */
+           {
+               U32 chars; /* how many chars to skip */
+               reg_trie_data * const trie
+                   = (reg_trie_data*)rexi->data->data[ARG(ST.me)];
+
+               assert((trie->wordinfo[ST.nextword].len - trie->prefixlen)
+                           >=  ST.firstchars);
+               chars = (trie->wordinfo[ST.nextword].len - trie->prefixlen)
+                           - ST.firstchars;
+               uc = ST.firstpos;
+
+               if (ST.longfold) {
+                   /* the hard option - fold each char in turn and find
+                    * its folded length (which may be different */
+                   U8 foldbuf[UTF8_MAXBYTES_CASE + 1];
+                   STRLEN foldlen;
+                   STRLEN len;
+                   UV uvc;
+                   U8 *uscan;
+
+                   while (chars) {
+                       if (utf8_target) {
+                           uvc = utf8n_to_uvuni((U8*)uc, UTF8_MAXLEN, &len,
+                                                   uniflags);
+                           uc += len;
+                       }
+                       else {
+                           uvc = *uc;
+                           uc++;
+                       }
+                       uvc = to_uni_fold(uvc, foldbuf, &foldlen);
+                       uscan = foldbuf;
+                       while (foldlen) {
+                           if (!--chars)
+                               break;
+                           uvc = utf8n_to_uvuni(uscan, UTF8_MAXLEN, &len,
+                                           uniflags);
+                           uscan += len;
+                           foldlen -= len;
+                       }
+                   }
+               }
+               else {
+                   if (utf8_target)
+                       while (chars--)
+                           uc += UTF8SKIP(uc);
+                   else
+                       uc += chars;
+               }
+           }
+
+           scan = ST.me + ((ST.jump && ST.jump[ST.nextword])
+                           ? ST.jump[ST.nextword]
+                           : NEXT_OFF(ST.me));
+
+           DEBUG_EXECUTE_r({
+               PerlIO_printf( Perl_debug_log,
+                   "%*s  %sTRIE matched word #%d, continuing%s\n",
+                   REPORT_CODE_OFF+depth*2, "", 
+                   PL_colors[4],
+                   ST.nextword,
+                   PL_colors[5]
+                   );
+           });
+
+           if (ST.accepted > 1 || has_cutgroup) {
+               PUSH_STATE_GOTO(TRIE_next, scan, (char*)uc);
+               assert(0); /* NOTREACHED */
+           }
+           /* only one choice left - just continue */
+           DEBUG_EXECUTE_r({
+               AV *const trie_words
+                   = MUTABLE_AV(rexi->data->data[ARG(ST.me)+TRIE_WORDS_OFFSET]);
+               SV ** const tmp = av_fetch( trie_words,
+                   ST.nextword-1, 0 );
+               SV *sv= tmp ? sv_newmortal() : NULL;
+
+               PerlIO_printf( Perl_debug_log,
+                   "%*s  %sonly one match left, short-circuiting: #%d <%s>%s\n",
+                   REPORT_CODE_OFF+depth*2, "", PL_colors[4],
+                   ST.nextword,
+                   tmp ? pv_pretty(sv, SvPV_nolen_const(*tmp), SvCUR(*tmp), 0,
+                           PL_colors[0], PL_colors[1],
+                           (SvUTF8(*tmp) ? PERL_PV_ESCAPE_UNI : 0)|PERL_PV_ESCAPE_NONASCII
+                       ) 
+                   : "not compiled under -Dr",
+                   PL_colors[5] );
+           });
+
+           locinput = (char*)uc;
+           continue; /* execute rest of RE */
+           assert(0); /* NOTREACHED */
+        }
+#undef  ST
+
+       case EXACT: {            /*  /abc/        */
+           char *s = STRING(scan);
+           ln = STR_LEN(scan);
+           if (utf8_target != UTF_PATTERN) {
+               /* The target and the pattern have differing utf8ness. */
+               char *l = locinput;
+               const char * const e = s + ln;
+
+               if (utf8_target) {
+                    /* The target is utf8, the pattern is not utf8.
+                     * Above-Latin1 code points can't match the pattern;
+                     * invariants match exactly, and the other Latin1 ones need
+                     * to be downgraded to a single byte in order to do the
+                     * comparison.  (If we could be confident that the target
+                     * is not malformed, this could be refactored to have fewer
+                     * tests by just assuming that if the first bytes match, it
+                     * is an invariant, but there are tests in the test suite
+                     * dealing with (??{...}) which violate this) */
+                   while (s < e) {
+                       if (l >= PL_regeol)
+                            sayNO;
+                        if (UTF8_IS_ABOVE_LATIN1(* (U8*) l)) {
+                            sayNO;
+                        }
+                        if (UTF8_IS_INVARIANT(*(U8*)l)) {
+                           if (*l != *s) {
+                                sayNO;
+                            }
+                            l++;
+                        }
+                        else {
+                            if (TWO_BYTE_UTF8_TO_UNI(*l, *(l+1)) != * (U8*) s) {
+                                sayNO;
+                            }
+                            l += 2;
+                        }
+                       s++;
+                   }
+               }
+               else {
+                   /* The target is not utf8, the pattern is utf8. */
+                   while (s < e) {
+                        if (l >= PL_regeol || UTF8_IS_ABOVE_LATIN1(* (U8*) s))
+                        {
+                            sayNO;
+                        }
+                        if (UTF8_IS_INVARIANT(*(U8*)s)) {
+                           if (*s != *l) {
+                                sayNO;
+                            }
+                            s++;
+                        }
+                        else {
+                            if (TWO_BYTE_UTF8_TO_UNI(*s, *(s+1)) != * (U8*) l) {
+                                sayNO;
+                            }
+                            s += 2;
+                        }
+                       l++;
+                   }
+               }
+               locinput = l;
+               break;
+           }
+           /* The target and the pattern have the same utf8ness. */
+           /* Inline the first character, for speed. */
+           if (UCHARAT(s) != nextchr)
+               sayNO;
+           if (PL_regeol - locinput < ln)
+               sayNO;
+           if (ln > 1 && memNE(s, locinput, ln))
+               sayNO;
+           locinput += ln;
+           break;
+           }
+
+       case EXACTFL: {          /*  /abc/il      */
+           re_fold_t folder;
+           const U8 * fold_array;
+           const char * s;
+           U32 fold_utf8_flags;
+
+           PL_reg_flags |= RF_tainted;
+           folder = foldEQ_locale;
+           fold_array = PL_fold_locale;
+           fold_utf8_flags = FOLDEQ_UTF8_LOCALE;
+           goto do_exactf;
+
+       case EXACTFU_SS:         /*  /\x{df}/iu   */
+       case EXACTFU_TRICKYFOLD: /*  /\x{390}/iu  */
+       case EXACTFU:            /*  /abc/iu      */
+           folder = foldEQ_latin1;
+           fold_array = PL_fold_latin1;
+           fold_utf8_flags = (UTF_PATTERN) ? FOLDEQ_S1_ALREADY_FOLDED : 0;
+           goto do_exactf;
+
+       case EXACTFA:            /*  /abc/iaa     */
+           folder = foldEQ_latin1;
+           fold_array = PL_fold_latin1;
+           fold_utf8_flags = FOLDEQ_UTF8_NOMIX_ASCII;
+           goto do_exactf;
+
+       case EXACTF:             /*  /abc/i       */
+           folder = foldEQ;
+           fold_array = PL_fold;
+           fold_utf8_flags = 0;
+
+         do_exactf:
+           s = STRING(scan);
+           ln = STR_LEN(scan);
+
+           if (utf8_target || UTF_PATTERN || state_num == EXACTFU_SS) {
+             /* Either target or the pattern are utf8, or has the issue where
+              * the fold lengths may differ. */
+               const char * const l = locinput;
+               char *e = PL_regeol;
+
+               if (! foldEQ_utf8_flags(s, 0,  ln, cBOOL(UTF_PATTERN),
+                                       l, &e, 0,  utf8_target, fold_utf8_flags))
+               {
+                   sayNO;
+               }
+               locinput = e;
+               break;
+           }
+
+           /* Neither the target nor the pattern are utf8 */
+           if (UCHARAT(s) != nextchr
+                && !NEXTCHR_IS_EOS
+               && UCHARAT(s) != fold_array[nextchr])
+           {
+               sayNO;
+           }
+           if (PL_regeol - locinput < ln)
+               sayNO;
+           if (ln > 1 && ! folder(s, locinput, ln))
+               sayNO;
+           locinput += ln;
+           break;
+       }
+
+       /* XXX Could improve efficiency by separating these all out using a
+        * macro or in-line function.  At that point regcomp.c would no longer
+        * have to set the FLAGS fields of these */
+       case BOUNDL:  /*  /\b/l  */
+       case NBOUNDL: /*  /\B/l  */
+           PL_reg_flags |= RF_tainted;
+           /* FALL THROUGH */
+       case BOUND:   /*  /\b/   */
+       case BOUNDU:  /*  /\b/u  */
+       case BOUNDA:  /*  /\b/a  */
+       case NBOUND:  /*  /\B/   */
+       case NBOUNDU: /*  /\B/u  */
+       case NBOUNDA: /*  /\B/a  */
+           /* was last char in word? */
+           if (utf8_target
+               && FLAGS(scan) != REGEX_ASCII_RESTRICTED_CHARSET
+               && FLAGS(scan) != REGEX_ASCII_MORE_RESTRICTED_CHARSET)
+           {
+               if (locinput == PL_bostr)
+                   ln = '\n';
+               else {
+                   const U8 * const r = reghop3((U8*)locinput, -1, (U8*)PL_bostr);
+
+                   ln = utf8n_to_uvchr(r, UTF8SKIP(r), 0, uniflags);
+               }
+               if (FLAGS(scan) != REGEX_LOCALE_CHARSET) {
+                   ln = isALNUM_uni(ln);
+                    if (NEXTCHR_IS_EOS)
+                        n = 0;
+                    else {
+                        LOAD_UTF8_CHARCLASS_ALNUM();
+                        n = swash_fetch(PL_utf8_alnum, (U8*)locinput,
+                                                                utf8_target);
+                    }
+               }
+               else {
+                   ln = isALNUM_LC_uvchr(UNI_TO_NATIVE(ln));
+                   n = NEXTCHR_IS_EOS ? 0 : isALNUM_LC_utf8((U8*)locinput);
+               }
+           }
+           else {
+
+               /* Here the string isn't utf8, or is utf8 and only ascii
+                * characters are to match \w.  In the latter case looking at
+                * the byte just prior to the current one may be just the final
+                * byte of a multi-byte character.  This is ok.  There are two
+                * cases:
+                * 1) it is a single byte character, and then the test is doing
+                *      just what it's supposed to.
+                * 2) it is a multi-byte character, in which case the final
+                *      byte is never mistakable for ASCII, and so the test
+                *      will say it is not a word character, which is the
+                *      correct answer. */
+               ln = (locinput != PL_bostr) ?
+                   UCHARAT(locinput - 1) : '\n';
+               switch (FLAGS(scan)) {
+                   case REGEX_UNICODE_CHARSET:
+                       ln = isWORDCHAR_L1(ln);
+                       n = NEXTCHR_IS_EOS ? 0 : isWORDCHAR_L1(nextchr);
+                       break;
+                   case REGEX_LOCALE_CHARSET:
+                       ln = isALNUM_LC(ln);
+                       n = NEXTCHR_IS_EOS ? 0 : isALNUM_LC(nextchr);
+                       break;
+                   case REGEX_DEPENDS_CHARSET:
+                       ln = isALNUM(ln);
+                       n = NEXTCHR_IS_EOS ? 0 : isALNUM(nextchr);
+                       break;
+                   case REGEX_ASCII_RESTRICTED_CHARSET:
+                   case REGEX_ASCII_MORE_RESTRICTED_CHARSET:
+                       ln = isWORDCHAR_A(ln);
+                       n = NEXTCHR_IS_EOS ? 0 : isWORDCHAR_A(nextchr);
+                       break;
+                   default:
+                       Perl_croak(aTHX_ "panic: Unexpected FLAGS %u in op %u", FLAGS(scan), OP(scan));
+                       break;
+               }
+           }
+           /* Note requires that all BOUNDs be lower than all NBOUNDs in
+            * regcomp.sym */
+           if (((!ln) == (!n)) == (OP(scan) < NBOUND))
+                   sayNO;
+           break;
+
+       case ANYOF:  /*  /[abc]/       */
+            if (NEXTCHR_IS_EOS)
+                sayNO;
+           if (utf8_target) {
+               if (!reginclass(rex, scan, (U8*)locinput, utf8_target))
+                   sayNO;
+               locinput += UTF8SKIP(locinput);
+               break;
+           }
+           else {
+               if (!REGINCLASS(rex, scan, (U8*)locinput))
+                   sayNO;
+               locinput++;
+               break;
+           }
+           break;
+
+       /* Special char classes: \d, \w etc.
+         * The defines start on line 166 or so */
+        CCC_TRY_U(ALNUM,  NALNUM,  isWORDCHAR,
+                 ALNUML, NALNUML, isALNUM_LC, isALNUM_LC_utf8,
+                 ALNUMU, NALNUMU, isWORDCHAR_L1,
+                 ALNUMA, NALNUMA, isWORDCHAR_A,
+                 alnum, "a");
+
+        case SPACEL:
+            PL_reg_flags |= RF_tainted;
+            if (NEXTCHR_IS_EOS) {
+                sayNO;
+            }
+            if (utf8_target && UTF8_IS_CONTINUED(nextchr)) {
+                if (! isSPACE_LC_utf8((U8 *) locinput)) {
+                    sayNO;
+                }
+            }
+            else if (! isSPACE_LC((U8) nextchr)) {
+                    sayNO;
+            }
+            goto increment_locinput;
+
+        case NSPACEL:
+            PL_reg_flags |= RF_tainted;
+            if (NEXTCHR_IS_EOS) {
+                sayNO;
+            }
+            if (utf8_target && UTF8_IS_CONTINUED(nextchr)) {
+                if (isSPACE_LC_utf8((U8 *) locinput)) {
+                    sayNO;
+                }
+            }
+            else if (isSPACE_LC(nextchr)) {
+                    sayNO;
+            }
+            goto increment_locinput;
+
+        case SPACE:
+            if (utf8_target) {
+                goto utf8_space;
+            }
+            /* FALL THROUGH */
+        case SPACEA:
+            if (NEXTCHR_IS_EOS || ! isSPACE_A(nextchr)) {
+                sayNO;
+            }
+            /* Matched a utf8-invariant, so don't have to worry about utf8 */
+            locinput++;
+            break;
+
+        case NSPACE:
+            if (utf8_target) {
+                goto utf8_nspace;
+            }
+            /* FALL THROUGH */
+        case NSPACEA:
+            if (NEXTCHR_IS_EOS || isSPACE_A(nextchr)) {
+                sayNO;
+            }
+            goto increment_locinput;
+
+        case SPACEU:
+          utf8_space:
+            if (NEXTCHR_IS_EOS || ! is_XPERLSPACE(locinput, utf8_target)) {
+                sayNO;
+            }
+            goto increment_locinput;
+
+        case NSPACEU:
+          utf8_nspace:
+            if (NEXTCHR_IS_EOS || is_XPERLSPACE(locinput, utf8_target)) {
+                sayNO;
+            }
+            goto increment_locinput;
+
+        CCC_TRY(DIGIT,  NDIGIT,  isDIGIT,
+               DIGITL, NDIGITL, isDIGIT_LC, isDIGIT_LC_utf8,
+               DIGITA, NDIGITA, isDIGIT_A,
+               digit, "0");
+
+        case POSIXA: /* /[[:ascii:]]/ etc */
+            if (NEXTCHR_IS_EOS || ! _generic_isCC_A(nextchr, FLAGS(scan))) {
+                sayNO;
+            }
+            /* Matched a utf8-invariant, so don't have to worry about utf8 */
+            locinput++;
+            break;
+
+        case NPOSIXA: /*  /[^[:ascii:]]/  etc */
+            if (NEXTCHR_IS_EOS || _generic_isCC_A(nextchr, FLAGS(scan))) {
+                sayNO;
+            }
+            goto increment_locinput;
+
+       case CLUMP: /* Match \X: logical Unicode character.  This is defined as
+                      a Unicode extended Grapheme Cluster */
+           /* From http://www.unicode.org/reports/tr29 (5.2 version).  An
+             extended Grapheme Cluster is:
+
+              CR LF
+              | Prepend* Begin Extend*
+              | .
+
+               Begin is:           ( Special_Begin | ! Control )
+               Special_Begin is:   ( Regional-Indicator+ | Hangul-syllable )
+               Extend is:          ( Grapheme_Extend | Spacing_Mark )
+               Control is:         [ GCB_Control  CR  LF ]
+               Hangul-syllable is: ( T+ | ( L* ( L | ( LVT | ( V | LV ) V* ) T* ) ))
+
+               If we create a 'Regular_Begin' = Begin - Special_Begin, then
+               we can rewrite
+
+                   Begin is ( Regular_Begin + Special Begin )
+
+               It turns out that 98.4% of all Unicode code points match
+               Regular_Begin.  Doing it this way eliminates a table match in
+               the previous implementation for almost all Unicode code points.
+
+              There is a subtlety with Prepend* which showed up in testing.
+              Note that the Begin, and only the Begin is required in:
+               | Prepend* Begin Extend*
+              Also, Begin contains '! Control'.  A Prepend must be a
+              '!  Control', which means it must also be a Begin.  What it
+              comes down to is that if we match Prepend* and then find no
+              suitable Begin afterwards, that if we backtrack the last
+              Prepend, that one will be a suitable Begin.
+           */
+
+           if (NEXTCHR_IS_EOS)
+               sayNO;
+           if  (! utf8_target) {
+
+               /* Match either CR LF  or '.', as all the other possibilities
+                * require utf8 */
+               locinput++;         /* Match the . or CR */
+               if (nextchr == '\r' /* And if it was CR, and the next is LF,
+                                      match the LF */
+                   && locinput < PL_regeol
+                   && UCHARAT(locinput) == '\n') locinput++;
+           }
+           else {
+
+               /* Utf8: See if is ( CR LF ); already know that locinput <
+                * PL_regeol, so locinput+1 is in bounds */
+               if ( nextchr == '\r' && locinput+1 < PL_regeol
+                        && UCHARAT(locinput + 1) == '\n')
+                {
+                   locinput += 2;
+               }
+               else {
+                    STRLEN len;
+
+                   /* In case have to backtrack to beginning, then match '.' */
+                   char *starting = locinput;
+
+                   /* In case have to backtrack the last prepend */
+                   char *previous_prepend = 0;
+
+                   LOAD_UTF8_CHARCLASS_GCB();
+
+                    /* Match (prepend)*   */
+                    while (locinput < PL_regeol
+                           && (len = is_GCB_Prepend_utf8(locinput)))
+                    {
+                        previous_prepend = locinput;
+                        locinput += len;
+                    }
+
+                   /* As noted above, if we matched a prepend character, but
+                    * the next thing won't match, back off the last prepend we
+                    * matched, as it is guaranteed to match the begin */
+                   if (previous_prepend
+                       && (locinput >=  PL_regeol
+                           || (! swash_fetch(PL_utf8_X_regular_begin,
+                                            (U8*)locinput, utf8_target)
+                                && ! is_GCB_SPECIAL_BEGIN_utf8(locinput)))
+                        )
+                   {
+                       locinput = previous_prepend;
+                   }
+
+                   /* Note that here we know PL_regeol > locinput, as we
+                    * tested that upon input to this switch case, and if we
+                    * moved locinput forward, we tested the result just above
+                    * and it either passed, or we backed off so that it will
+                    * now pass */
+                   if (swash_fetch(PL_utf8_X_regular_begin,
+                                    (U8*)locinput, utf8_target)) {
+                        locinput += UTF8SKIP(locinput);
+                    }
+                    else if (! is_GCB_SPECIAL_BEGIN_utf8(locinput)) {
+
+                       /* Here did not match the required 'Begin' in the
+                        * second term.  So just match the very first
+                        * character, the '.' of the final term of the regex */
+                       locinput = starting + UTF8SKIP(starting);
+                        goto exit_utf8;
+                   } else {
+
+                        /* Here is a special begin.  It can be composed of
+                         * several individual characters.  One possibility is
+                         * RI+ */
+                        if ((len = is_GCB_RI_utf8(locinput))) {
+                            locinput += len;
+                            while (locinput < PL_regeol
+                                   && (len = is_GCB_RI_utf8(locinput)))
+                            {
+                                locinput += len;
+                            }
+                        } else if ((len = is_GCB_T_utf8(locinput))) {
+                            /* Another possibility is T+ */
+                            locinput += len;
+                            while (locinput < PL_regeol
+                                && (len = is_GCB_T_utf8(locinput)))
+                            {
+                                locinput += len;
+                            }
+                        } else {
+
+                            /* Here, neither RI+ nor T+; must be some other
+                             * Hangul.  That means it is one of the others: L,
+                             * LV, LVT or V, and matches:
+                             * L* (L | LVT T* | V * V* T* | LV  V* T*) */
+
+                            /* Match L*           */
+                            while (locinput < PL_regeol
+                                   && (len = is_GCB_L_utf8(locinput)))
+                            {
+                                locinput += len;
+                            }
+
+                            /* Here, have exhausted L*.  If the next character
+                             * is not an LV, LVT nor V, it means we had to have
+                             * at least one L, so matches L+ in the original
+                             * equation, we have a complete hangul syllable.
+                             * Are done. */
+
+                            if (locinput < PL_regeol
+                                && is_GCB_LV_LVT_V_utf8(locinput))
+                            {
+
+                                /* Otherwise keep going.  Must be LV, LVT or V.
+                                 * See if LVT */
+                                if (is_utf8_X_LVT((U8*)locinput)) {
+                                    locinput += UTF8SKIP(locinput);
+                                } else {
+
+                                    /* Must be  V or LV.  Take it, then match
+                                     * V*     */
+                                    locinput += UTF8SKIP(locinput);
+                                    while (locinput < PL_regeol
+                                           && (len = is_GCB_V_utf8(locinput)))
+                                    {
+                                        locinput += len;
+                                    }
+                                }
+
+                                /* And any of LV, LVT, or V can be followed
+                                 * by T*            */
+                                while (locinput < PL_regeol
+                                       && (len = is_GCB_T_utf8(locinput)))
+                                {
+                                    locinput += len;
+                                }
+                            }
+                        }
+                    }
+
+                    /* Match any extender */
+                    while (locinput < PL_regeol
+                            && swash_fetch(PL_utf8_X_extend,
+                                            (U8*)locinput, utf8_target))
+                    {
+                        locinput += UTF8SKIP(locinput);
+                    }
+               }
+            exit_utf8:
+               if (locinput > PL_regeol) sayNO;
+           }
+           break;
+            
+       case NREFFL:  /*  /\g{name}/il  */
+       {   /* The capture buffer cases.  The ones beginning with N for the
+              named buffers just convert to the equivalent numbered and
+              pretend they were called as the corresponding numbered buffer
+              op.  */
+           /* don't initialize these in the declaration, it makes C++
+              unhappy */
+           char *s;
+           char type;
+           re_fold_t folder;
+           const U8 *fold_array;
+           UV utf8_fold_flags;
+
+           PL_reg_flags |= RF_tainted;
+           folder = foldEQ_locale;
+           fold_array = PL_fold_locale;
+           type = REFFL;
+           utf8_fold_flags = FOLDEQ_UTF8_LOCALE;
+           goto do_nref;
+
+       case NREFFA:  /*  /\g{name}/iaa  */
+           folder = foldEQ_latin1;
+           fold_array = PL_fold_latin1;
+           type = REFFA;
+           utf8_fold_flags = FOLDEQ_UTF8_NOMIX_ASCII;
+           goto do_nref;
+
+       case NREFFU:  /*  /\g{name}/iu  */
+           folder = foldEQ_latin1;
+           fold_array = PL_fold_latin1;
+           type = REFFU;
+           utf8_fold_flags = 0;
+           goto do_nref;
+
+       case NREFF:  /*  /\g{name}/i  */
+           folder = foldEQ;
+           fold_array = PL_fold;
+           type = REFF;
+           utf8_fold_flags = 0;
+           goto do_nref;
+
+       case NREF:  /*  /\g{name}/   */
+           type = REF;
+           folder = NULL;
+           fold_array = NULL;
+           utf8_fold_flags = 0;
+         do_nref:
+
+           /* For the named back references, find the corresponding buffer
+            * number */
+           n = reg_check_named_buff_matched(rex,scan);
+
+            if ( ! n ) {
+                sayNO;
+           }
+           goto do_nref_ref_common;
+
+       case REFFL:  /*  /\1/il  */
+           PL_reg_flags |= RF_tainted;
+           folder = foldEQ_locale;
+           fold_array = PL_fold_locale;
+           utf8_fold_flags = FOLDEQ_UTF8_LOCALE;
+           goto do_ref;
+
+       case REFFA:  /*  /\1/iaa  */
+           folder = foldEQ_latin1;
+           fold_array = PL_fold_latin1;
+           utf8_fold_flags = FOLDEQ_UTF8_NOMIX_ASCII;
+           goto do_ref;
+
+       case REFFU:  /*  /\1/iu  */
+           folder = foldEQ_latin1;
+           fold_array = PL_fold_latin1;
+           utf8_fold_flags = 0;
+           goto do_ref;
+
+       case REFF:  /*  /\1/i  */
+           folder = foldEQ;
+           fold_array = PL_fold;
+           utf8_fold_flags = 0;
+           goto do_ref;
+
+        case REF:  /*  /\1/    */
+           folder = NULL;
+           fold_array = NULL;
+           utf8_fold_flags = 0;
+
+         do_ref:
+           type = OP(scan);
+           n = ARG(scan);  /* which paren pair */
+
+         do_nref_ref_common:
+           ln = rex->offs[n].start;
+           PL_reg_leftiter = PL_reg_maxiter;           /* Void cache */
+           if (rex->lastparen < n || ln == -1)
+               sayNO;                  /* Do not match unless seen CLOSEn. */
+           if (ln == rex->offs[n].end)
+               break;
+
+           s = PL_bostr + ln;
+           if (type != REF     /* REF can do byte comparison */
+               && (utf8_target || type == REFFU))
+           { /* XXX handle REFFL better */
+               char * limit = PL_regeol;
+
+               /* This call case insensitively compares the entire buffer
+                   * at s, with the current input starting at locinput, but
+                   * not going off the end given by PL_regeol, and returns in
+                   * <limit> upon success, how much of the current input was
+                   * matched */
+               if (! foldEQ_utf8_flags(s, NULL, rex->offs[n].end - ln, utf8_target,
+                                   locinput, &limit, 0, utf8_target, utf8_fold_flags))
+               {
+                   sayNO;
+               }
+               locinput = limit;
+               break;
+           }
+
+           /* Not utf8:  Inline the first character, for speed. */
+           if (!NEXTCHR_IS_EOS &&
+                UCHARAT(s) != nextchr &&
+               (type == REF ||
+                UCHARAT(s) != fold_array[nextchr]))
+               sayNO;
+           ln = rex->offs[n].end - ln;
+           if (locinput + ln > PL_regeol)
+               sayNO;
+           if (ln > 1 && (type == REF
+                          ? memNE(s, locinput, ln)
+                          : ! folder(s, locinput, ln)))
+               sayNO;
+           locinput += ln;
+           break;
+       }
+
+       case NOTHING: /* null op; e.g. the 'nothing' following
+                       * the '*' in m{(a+|b)*}' */
+           break;
+       case TAIL: /* placeholder while compiling (A|B|C) */
+           break;
+
+       case BACK: /* ??? doesn't appear to be used ??? */
+           break;
+
+#undef  ST
+#define ST st->u.eval
+       {
+           SV *ret;
+           REGEXP *re_sv;
+            regexp *re;
+            regexp_internal *rei;
+            regnode *startpoint;
+
+       case GOSTART: /*  (?R)  */
+       case GOSUB: /*    /(...(?1))/   /(...(?&foo))/   */
+           if (cur_eval && cur_eval->locinput==locinput) {
+                if (cur_eval->u.eval.close_paren == (U32)ARG(scan)) 
+                    Perl_croak(aTHX_ "Infinite recursion in regex");
+                if ( ++nochange_depth > max_nochange_depth )
+                    Perl_croak(aTHX_ 
+                        "Pattern subroutine nesting without pos change"
+                        " exceeded limit in regex");
+            } else {
+                nochange_depth = 0;
+            }
+           re_sv = rex_sv;
+            re = rex;
+            rei = rexi;
+            if (OP(scan)==GOSUB) {
+                startpoint = scan + ARG2L(scan);
+                ST.close_paren = ARG(scan);
+            } else {
+                startpoint = rei->program+1;
+                ST.close_paren = 0;
+            }
+            goto eval_recurse_doit;
+            assert(0); /* NOTREACHED */
+
+        case EVAL:  /*   /(?{A})B/   /(??{A})B/  and /(?(?{A})X|Y)B/   */        
+            if (cur_eval && cur_eval->locinput==locinput) {
+               if ( ++nochange_depth > max_nochange_depth )
+                    Perl_croak(aTHX_ "EVAL without pos change exceeded limit in regex");
+            } else {
+                nochange_depth = 0;
+            }    
+           {
+               /* execute the code in the {...} */
+
+               dSP;
+               PADOFFSET before;
+               OP * const oop = PL_op;
+               COP * const ocurcop = PL_curcop;
+               OP *nop;
+               char *saved_regeol = PL_regeol;
+               struct re_save_state saved_state;
+               CV *newcv;
+
+               /* save *all* paren positions */
+               regcppush(rex, 0);
+               REGCP_SET(runops_cp);
+
+               /* To not corrupt the existing regex state while executing the
+                * eval we would normally put it on the save stack, like with
+                * save_re_context. However, re-evals have a weird scoping so we
+                * can't just add ENTER/LEAVE here. With that, things like
+                *
+                *    (?{$a=2})(a(?{local$a=$a+1}))*aak*c(?{$b=$a})
+                *
+                * would break, as they expect the localisation to be unwound
+                * only when the re-engine backtracks through the bit that
+                * localised it.
+                *
+                * What we do instead is just saving the state in a local c
+                * variable.
+                */
+               Copy(&PL_reg_state, &saved_state, 1, struct re_save_state);
+
+               PL_reg_state.re_reparsing = FALSE;
+
+               if (!caller_cv)
+                   caller_cv = find_runcv(NULL);
+
+               n = ARG(scan);
+
+               if (rexi->data->what[n] == 'r') { /* code from an external qr */
+                   newcv = (ReANY(
+                                               (REGEXP*)(rexi->data->data[n])
+                                           ))->qr_anoncv
+                                       ;
+                   nop = (OP*)rexi->data->data[n+1];
+               }
+               else if (rexi->data->what[n] == 'l') { /* literal code */
+                   newcv = caller_cv;
+                   nop = (OP*)rexi->data->data[n];
+                   assert(CvDEPTH(newcv));
+               }
+               else {
+                   /* literal with own CV */
+                   assert(rexi->data->what[n] == 'L');
+                   newcv = rex->qr_anoncv;
+                   nop = (OP*)rexi->data->data[n];
+               }
+
+               /* normally if we're about to execute code from the same
+                * CV that we used previously, we just use the existing
+                * CX stack entry. However, its possible that in the
+                * meantime we may have backtracked, popped from the save
+                * stack, and undone the SAVECOMPPAD(s) associated with
+                * PUSH_MULTICALL; in which case PL_comppad no longer
+                * points to newcv's pad. */
+               if (newcv != last_pushed_cv || PL_comppad != last_pad)
+               {
+                   I32 depth = (newcv == caller_cv) ? 0 : 1;
+                   if (last_pushed_cv) {
+                       CHANGE_MULTICALL_WITHDEPTH(newcv, depth);
+                   }
+                   else {
+                       PUSH_MULTICALL_WITHDEPTH(newcv, depth);
+                   }
+                   last_pushed_cv = newcv;
+               }
+               last_pad = PL_comppad;
+
+               /* the initial nextstate you would normally execute
+                * at the start of an eval (which would cause error
+                * messages to come from the eval), may be optimised
+                * away from the execution path in the regex code blocks;
+                * so manually set PL_curcop to it initially */
+               {
+                   OP *o = cUNOPx(nop)->op_first;
+                   assert(o->op_type == OP_NULL);
+                   if (o->op_targ == OP_SCOPE) {
+                       o = cUNOPo->op_first;
+                   }
+                   else {
+                       assert(o->op_targ == OP_LEAVE);
+                       o = cUNOPo->op_first;
+                       assert(o->op_type == OP_ENTER);
+                       o = o->op_sibling;
+                   }
+
+                   if (o->op_type != OP_STUB) {
+                       assert(    o->op_type == OP_NEXTSTATE
+                               || o->op_type == OP_DBSTATE
+                               || (o->op_type == OP_NULL
+                                   &&  (  o->op_targ == OP_NEXTSTATE
+                                       || o->op_targ == OP_DBSTATE
+                                       )
+                                   )
+                       );
+                       PL_curcop = (COP*)o;
+                   }
+               }
+               nop = nop->op_next;
+
+               DEBUG_STATE_r( PerlIO_printf(Perl_debug_log, 
+                   "  re EVAL PL_op=0x%"UVxf"\n", PTR2UV(nop)) );
+
+               rex->offs[0].end = PL_reg_magic->mg_len = locinput - PL_bostr;
+
+                if (sv_yes_mark) {
+                    SV *sv_mrk = get_sv("REGMARK", 1);
+                    sv_setsv(sv_mrk, sv_yes_mark);
+                }
+
+               /* we don't use MULTICALL here as we want to call the
+                * first op of the block of interest, rather than the
+                * first op of the sub */
+               before = SP-PL_stack_base;
+               PL_op = nop;
+               CALLRUNOPS(aTHX);                       /* Scalar context. */
+               SPAGAIN;
+               if (SP-PL_stack_base == before)
+                   ret = &PL_sv_undef;   /* protect against empty (?{}) blocks. */
+               else {
+                   ret = POPs;
+                   PUTBACK;
+               }
+
+               /* before restoring everything, evaluate the returned
+                * value, so that 'uninit' warnings don't use the wrong
+                * PL_op or pad. Also need to process any magic vars
+                * (e.g. $1) *before* parentheses are restored */
+
+               PL_op = NULL;
+
+                re_sv = NULL;
+               if (logical == 0)        /*   (?{})/   */
+                   sv_setsv(save_scalar(PL_replgv), ret); /* $^R */
+               else if (logical == 1) { /*   /(?(?{...})X|Y)/    */
+                   sw = cBOOL(SvTRUE(ret));
+                   logical = 0;
+               }
+               else {                   /*  /(??{})  */
+                   /*  if its overloaded, let the regex compiler handle
+                    *  it; otherwise extract regex, or stringify  */
+                   if (!SvAMAGIC(ret)) {
+                       SV *sv = ret;
+                       if (SvROK(sv))
+                           sv = SvRV(sv);
+                       if (SvTYPE(sv) == SVt_REGEXP)
+                           re_sv = (REGEXP*) sv;
+                       else if (SvSMAGICAL(sv)) {
+                           MAGIC *mg = mg_find(sv, PERL_MAGIC_qr);
+                           if (mg)
+                               re_sv = (REGEXP *) mg->mg_obj;
+                       }
+
+                       /* force any magic, undef warnings here */
+                       if (!re_sv) {
+                           ret = sv_mortalcopy(ret);
+                           (void) SvPV_force_nolen(ret);
+                       }
+                   }
+
+               }
+
+               Copy(&saved_state, &PL_reg_state, 1, struct re_save_state);
+
+               /* *** Note that at this point we don't restore
+                * PL_comppad, (or pop the CxSUB) on the assumption it may
+                * be used again soon. This is safe as long as nothing
+                * in the regexp code uses the pad ! */
+               PL_op = oop;
+               PL_curcop = ocurcop;
+               PL_regeol = saved_regeol;
+               S_regcp_restore(aTHX_ rex, runops_cp);
+
+               if (logical != 2)
+                   break;
+           }
+
+               /* only /(??{})/  from now on */
+               logical = 0;
+               {
+                   /* extract RE object from returned value; compiling if
+                    * necessary */
+
+                   if (re_sv) {
+                       re_sv = reg_temp_copy(NULL, re_sv);
+                   }
+                   else {
+                       U32 pm_flags = 0;
+                       const I32 osize = PL_regsize;
+
+                       if (SvUTF8(ret) && IN_BYTES) {
+                           /* In use 'bytes': make a copy of the octet
+                            * sequence, but without the flag on */
+                           STRLEN len;
+                           const char *const p = SvPV(ret, len);
+                           ret = newSVpvn_flags(p, len, SVs_TEMP);
+                       }
+                       if (rex->intflags & PREGf_USE_RE_EVAL)
+                           pm_flags |= PMf_USE_RE_EVAL;
+
+                       /* if we got here, it should be an engine which
+                        * supports compiling code blocks and stuff */
+                       assert(rex->engine && rex->engine->op_comp);
+                        assert(!(scan->flags & ~RXf_PMf_COMPILETIME));
+                       re_sv = rex->engine->op_comp(aTHX_ &ret, 1, NULL,
+                                   rex->engine, NULL, NULL,
+                                    /* copy /msix etc to inner pattern */
+                                    scan->flags,
+                                    pm_flags);
+
+                       if (!(SvFLAGS(ret)
+                             & (SVs_TEMP | SVs_PADTMP | SVf_READONLY
+                                | SVs_GMG))) {
+                           /* This isn't a first class regexp. Instead, it's
+                              caching a regexp onto an existing, Perl visible
+                              scalar.  */
+                           sv_magic(ret, MUTABLE_SV(re_sv), PERL_MAGIC_qr, 0, 0);
+                       }
+                       PL_regsize = osize;
+                       /* safe to do now that any $1 etc has been
+                        * interpolated into the new pattern string and
+                        * compiled */
+                       S_regcp_restore(aTHX_ rex, runops_cp);
+                   }
+                   SAVEFREESV(re_sv);
+                   re = ReANY(re_sv);
+               }
+                RXp_MATCH_COPIED_off(re);
+                re->subbeg = rex->subbeg;
+                re->sublen = rex->sublen;
+                re->suboffset = rex->suboffset;
+                re->subcoffset = rex->subcoffset;
+               rei = RXi_GET(re);
+                DEBUG_EXECUTE_r(
+                    debug_start_match(re_sv, utf8_target, locinput, PL_regeol,
+                        "Matching embedded");
+               );              
+               startpoint = rei->program + 1;
+                       ST.close_paren = 0; /* only used for GOSUB */
+
+        eval_recurse_doit: /* Share code with GOSUB below this line */                         
+               /* run the pattern returned from (??{...}) */
+               ST.cp = regcppush(rex, 0);      /* Save *all* the positions. */
+               REGCP_SET(ST.lastcp);
+               
+               re->lastparen = 0;
+               re->lastcloseparen = 0;
+
+               PL_regsize = 0;
+
+               /* XXXX This is too dramatic a measure... */
+               PL_reg_maxiter = 0;
+
+               ST.toggle_reg_flags = PL_reg_flags;
+               if (RX_UTF8(re_sv))
+                   PL_reg_flags |= RF_utf8;
+               else
+                   PL_reg_flags &= ~RF_utf8;
+               ST.toggle_reg_flags ^= PL_reg_flags; /* diff of old and new */
+
+               ST.prev_rex = rex_sv;
+               ST.prev_curlyx = cur_curlyx;
+               rex_sv = re_sv;
+               SET_reg_curpm(rex_sv);
+               rex = re;
+               rexi = rei;
+               cur_curlyx = NULL;
+               ST.B = next;
+               ST.prev_eval = cur_eval;
+               cur_eval = st;
+               /* now continue from first node in postoned RE */
+               PUSH_YES_STATE_GOTO(EVAL_AB, startpoint, locinput);
+               assert(0); /* NOTREACHED */
+       }
+
+       case EVAL_AB: /* cleanup after a successful (??{A})B */
+           /* note: this is called twice; first after popping B, then A */
+           PL_reg_flags ^= ST.toggle_reg_flags; 
+           rex_sv = ST.prev_rex;
+           SET_reg_curpm(rex_sv);
+           rex = ReANY(rex_sv);
+           rexi = RXi_GET(rex);
+           regcpblow(ST.cp);
+           cur_eval = ST.prev_eval;
+           cur_curlyx = ST.prev_curlyx;
+
+           /* XXXX This is too dramatic a measure... */
+           PL_reg_maxiter = 0;
+            if ( nochange_depth )
+               nochange_depth--;
+           sayYES;
+
+
+       case EVAL_AB_fail: /* unsuccessfully ran A or B in (??{A})B */
+           /* note: this is called twice; first after popping B, then A */
+           PL_reg_flags ^= ST.toggle_reg_flags; 
+           rex_sv = ST.prev_rex;
+           SET_reg_curpm(rex_sv);
+           rex = ReANY(rex_sv);
+           rexi = RXi_GET(rex); 
+
+           REGCP_UNWIND(ST.lastcp);
+           regcppop(rex);
+           cur_eval = ST.prev_eval;
+           cur_curlyx = ST.prev_curlyx;
+           /* XXXX This is too dramatic a measure... */
+           PL_reg_maxiter = 0;
+           if ( nochange_depth )
+               nochange_depth--;
+           sayNO_SILENT;
+#undef ST
+
+       case OPEN: /*  (  */
+           n = ARG(scan);  /* which paren pair */
+           rex->offs[n].start_tmp = locinput - PL_bostr;
+           if (n > PL_regsize)
+               PL_regsize = n;
+           DEBUG_BUFFERS_r(PerlIO_printf(Perl_debug_log,
+               "rex=0x%"UVxf" offs=0x%"UVxf": \\%"UVuf": set %"IVdf" tmp; regsize=%"UVuf"\n",
+               PTR2UV(rex),
+               PTR2UV(rex->offs),
+               (UV)n,
+               (IV)rex->offs[n].start_tmp,
+               (UV)PL_regsize
+           ));
+            lastopen = n;
+           break;
+
+/* XXX really need to log other places start/end are set too */
+#define CLOSE_CAPTURE \
+    rex->offs[n].start = rex->offs[n].start_tmp; \
+    rex->offs[n].end = locinput - PL_bostr; \
+    DEBUG_BUFFERS_r(PerlIO_printf(Perl_debug_log, \
+       "rex=0x%"UVxf" offs=0x%"UVxf": \\%"UVuf": set %"IVdf"..%"IVdf"\n", \
+       PTR2UV(rex), \
+       PTR2UV(rex->offs), \
+       (UV)n, \
+       (IV)rex->offs[n].start, \
+       (IV)rex->offs[n].end \
+    ))
+
+       case CLOSE:  /*  )  */
+           n = ARG(scan);  /* which paren pair */
+           CLOSE_CAPTURE;
+           /*if (n > PL_regsize)
+               PL_regsize = n;*/
+           if (n > rex->lastparen)
+               rex->lastparen = n;
+           rex->lastcloseparen = n;
+            if (cur_eval && cur_eval->u.eval.close_paren == n) {
+               goto fake_end;
+           }    
+           break;
+
+        case ACCEPT:  /*  (*ACCEPT)  */
+            if (ARG(scan)){
+                regnode *cursor;
+                for (cursor=scan;
+                     cursor && OP(cursor)!=END; 
+                     cursor=regnext(cursor)) 
+                {
+                    if ( OP(cursor)==CLOSE ){
+                        n = ARG(cursor);
+                        if ( n <= lastopen ) {
+                           CLOSE_CAPTURE;
+                            /*if (n > PL_regsize)
+                            PL_regsize = n;*/
+                            if (n > rex->lastparen)
+                                rex->lastparen = n;
+                            rex->lastcloseparen = n;
+                            if ( n == ARG(scan) || (cur_eval &&
+                                cur_eval->u.eval.close_paren == n))
+                                break;
+                        }
+                    }
+                }
+            }
+           goto fake_end;
+           /*NOTREACHED*/          
+
+       case GROUPP:  /*  (?(1))  */
+           n = ARG(scan);  /* which paren pair */
+           sw = cBOOL(rex->lastparen >= n && rex->offs[n].end != -1);
+           break;
+
+       case NGROUPP:  /*  (?(<name>))  */
+           /* reg_check_named_buff_matched returns 0 for no match */
+           sw = cBOOL(0 < reg_check_named_buff_matched(rex,scan));
+           break;
+
+        case INSUBP:   /*  (?(R))  */
+            n = ARG(scan);
+            sw = (cur_eval && (!n || cur_eval->u.eval.close_paren == n));
+            break;
+
+        case DEFINEP:  /*  (?(DEFINE))  */
+            sw = 0;
+            break;
+
+       case IFTHEN:   /*  (?(cond)A|B)  */
+           PL_reg_leftiter = PL_reg_maxiter;           /* Void cache */
+           if (sw)
+               next = NEXTOPER(NEXTOPER(scan));
+           else {
+               next = scan + ARG(scan);
+               if (OP(next) == IFTHEN) /* Fake one. */
+                   next = NEXTOPER(NEXTOPER(next));
+           }
+           break;
+
+       case LOGICAL:  /* modifier for EVAL and IFMATCH */
+           logical = scan->flags;
+           break;
+
+/*******************************************************************
+
+The CURLYX/WHILEM pair of ops handle the most generic case of the /A*B/
+pattern, where A and B are subpatterns. (For simple A, CURLYM or
+STAR/PLUS/CURLY/CURLYN are used instead.)
+
+A*B is compiled as <CURLYX><A><WHILEM><B>
+
+On entry to the subpattern, CURLYX is called. This pushes a CURLYX
+state, which contains the current count, initialised to -1. It also sets
+cur_curlyx to point to this state, with any previous value saved in the
+state block.
+
+CURLYX then jumps straight to the WHILEM op, rather than executing A,
+since the pattern may possibly match zero times (i.e. it's a while {} loop
+rather than a do {} while loop).
+
+Each entry to WHILEM represents a successful match of A. The count in the
+CURLYX block is incremented, another WHILEM state is pushed, and execution
+passes to A or B depending on greediness and the current count.
+
+For example, if matching against the string a1a2a3b (where the aN are
+substrings that match /A/), then the match progresses as follows: (the
+pushed states are interspersed with the bits of strings matched so far):
+
+    <CURLYX cnt=-1>
+    <CURLYX cnt=0><WHILEM>
+    <CURLYX cnt=1><WHILEM> a1 <WHILEM>
+    <CURLYX cnt=2><WHILEM> a1 <WHILEM> a2 <WHILEM>
+    <CURLYX cnt=3><WHILEM> a1 <WHILEM> a2 <WHILEM> a3 <WHILEM>
+    <CURLYX cnt=3><WHILEM> a1 <WHILEM> a2 <WHILEM> a3 <WHILEM> b
+
+(Contrast this with something like CURLYM, which maintains only a single
+backtrack state:
+
+    <CURLYM cnt=0> a1
+    a1 <CURLYM cnt=1> a2
+    a1 a2 <CURLYM cnt=2> a3
+    a1 a2 a3 <CURLYM cnt=3> b
+)
+
+Each WHILEM state block marks a point to backtrack to upon partial failure
+of A or B, and also contains some minor state data related to that
+iteration.  The CURLYX block, pointed to by cur_curlyx, contains the
+overall state, such as the count, and pointers to the A and B ops.
+
+This is complicated slightly by nested CURLYX/WHILEM's. Since cur_curlyx
+must always point to the *current* CURLYX block, the rules are:
+
+When executing CURLYX, save the old cur_curlyx in the CURLYX state block,
+and set cur_curlyx to point the new block.
+
+When popping the CURLYX block after a successful or unsuccessful match,
+restore the previous cur_curlyx.
+
+When WHILEM is about to execute B, save the current cur_curlyx, and set it
+to the outer one saved in the CURLYX block.
+
+When popping the WHILEM block after a successful or unsuccessful B match,
+restore the previous cur_curlyx.
+
+Here's an example for the pattern (AI* BI)*BO
+I and O refer to inner and outer, C and W refer to CURLYX and WHILEM:
+
+cur_
+curlyx backtrack stack
+------ ---------------
+NULL   
+CO     <CO prev=NULL> <WO>
+CI     <CO prev=NULL> <WO> <CI prev=CO> <WI> ai 
+CO     <CO prev=NULL> <WO> <CI prev=CO> <WI> ai <WI prev=CI> bi 
+NULL   <CO prev=NULL> <WO> <CI prev=CO> <WI> ai <WI prev=CI> bi <WO prev=CO> bo
+
+At this point the pattern succeeds, and we work back down the stack to
+clean up, restoring as we go:
+
+CO     <CO prev=NULL> <WO> <CI prev=CO> <WI> ai <WI prev=CI> bi 
+CI     <CO prev=NULL> <WO> <CI prev=CO> <WI> ai 
+CO     <CO prev=NULL> <WO>
+NULL   
+
+*******************************************************************/
+
+#define ST st->u.curlyx
+
+       case CURLYX:    /* start of /A*B/  (for complex A) */
+       {
+           /* No need to save/restore up to this paren */
+           I32 parenfloor = scan->flags;
+           
+           assert(next); /* keep Coverity happy */
+           if (OP(PREVOPER(next)) == NOTHING) /* LONGJMP */
+               next += ARG(next);
+
+           /* XXXX Probably it is better to teach regpush to support
+              parenfloor > PL_regsize... */
+           if (parenfloor > (I32)rex->lastparen)
+               parenfloor = rex->lastparen; /* Pessimization... */
+
+           ST.prev_curlyx= cur_curlyx;
+           cur_curlyx = st;
+           ST.cp = PL_savestack_ix;
+
+           /* these fields contain the state of the current curly.
+            * they are accessed by subsequent WHILEMs */
+           ST.parenfloor = parenfloor;
+           ST.me = scan;
+           ST.B = next;
+           ST.minmod = minmod;
+           minmod = 0;
+           ST.count = -1;      /* this will be updated by WHILEM */
+           ST.lastloc = NULL;  /* this will be updated by WHILEM */
+
+           PUSH_YES_STATE_GOTO(CURLYX_end, PREVOPER(next), locinput);
+           assert(0); /* NOTREACHED */
+       }
+
+       case CURLYX_end: /* just finished matching all of A*B */
+           cur_curlyx = ST.prev_curlyx;
+           sayYES;
+           assert(0); /* NOTREACHED */
+
+       case CURLYX_end_fail: /* just failed to match all of A*B */
+           regcpblow(ST.cp);
+           cur_curlyx = ST.prev_curlyx;
+           sayNO;
+           assert(0); /* NOTREACHED */
+
+
+#undef ST
+#define ST st->u.whilem
+
+       case WHILEM:     /* just matched an A in /A*B/  (for complex A) */
+       {
+           /* see the discussion above about CURLYX/WHILEM */
+           I32 n;
+           int min = ARG1(cur_curlyx->u.curlyx.me);
+           int max = ARG2(cur_curlyx->u.curlyx.me);
+           regnode *A = NEXTOPER(cur_curlyx->u.curlyx.me) + EXTRA_STEP_2ARGS;
+
+           assert(cur_curlyx); /* keep Coverity happy */
+           n = ++cur_curlyx->u.curlyx.count; /* how many A's matched */
+           ST.save_lastloc = cur_curlyx->u.curlyx.lastloc;
+           ST.cache_offset = 0;
+           ST.cache_mask = 0;
+           
+
+           DEBUG_EXECUTE_r( PerlIO_printf(Perl_debug_log,
+                 "%*s  whilem: matched %ld out of %d..%d\n",
+                 REPORT_CODE_OFF+depth*2, "", (long)n, min, max)
+           );
+
+           /* First just match a string of min A's. */
+
+           if (n < min) {
+               ST.cp = regcppush(rex, cur_curlyx->u.curlyx.parenfloor);
+               cur_curlyx->u.curlyx.lastloc = locinput;
+               REGCP_SET(ST.lastcp);
+
+               PUSH_STATE_GOTO(WHILEM_A_pre, A, locinput);
+               assert(0); /* NOTREACHED */
+           }
+
+           /* If degenerate A matches "", assume A done. */
+
+           if (locinput == cur_curlyx->u.curlyx.lastloc) {
+               DEBUG_EXECUTE_r( PerlIO_printf(Perl_debug_log,
+                  "%*s  whilem: empty match detected, trying continuation...\n",
+                  REPORT_CODE_OFF+depth*2, "")
+               );
+               goto do_whilem_B_max;
+           }
+
+           /* super-linear cache processing */
+
+           if (scan->flags) {
+
+               if (!PL_reg_maxiter) {
+                   /* start the countdown: Postpone detection until we
+                    * know the match is not *that* much linear. */
+                   PL_reg_maxiter = (PL_regeol - PL_bostr + 1) * (scan->flags>>4);
+                   /* possible overflow for long strings and many CURLYX's */
+                   if (PL_reg_maxiter < 0)
+                       PL_reg_maxiter = I32_MAX;
+                   PL_reg_leftiter = PL_reg_maxiter;
+               }
+
+               if (PL_reg_leftiter-- == 0) {
+                   /* initialise cache */
+                   const I32 size = (PL_reg_maxiter + 7)/8;
+                   if (PL_reg_poscache) {
+                       if ((I32)PL_reg_poscache_size < size) {
+                           Renew(PL_reg_poscache, size, char);
+                           PL_reg_poscache_size = size;
+                       }
+                       Zero(PL_reg_poscache, size, char);
+                   }
+                   else {
+                       PL_reg_poscache_size = size;
+                       Newxz(PL_reg_poscache, size, char);
+                   }
+                   DEBUG_EXECUTE_r( PerlIO_printf(Perl_debug_log,
+      "%swhilem: Detected a super-linear match, switching on caching%s...\n",
+                             PL_colors[4], PL_colors[5])
+                   );
+               }
+
+               if (PL_reg_leftiter < 0) {
+                   /* have we already failed at this position? */
+                   I32 offset, mask;
+                   offset  = (scan->flags & 0xf) - 1
+                               + (locinput - PL_bostr)  * (scan->flags>>4);
+                   mask    = 1 << (offset % 8);
+                   offset /= 8;
+                   if (PL_reg_poscache[offset] & mask) {
+                       DEBUG_EXECUTE_r( PerlIO_printf(Perl_debug_log,
+                           "%*s  whilem: (cache) already tried at this position...\n",
+                           REPORT_CODE_OFF+depth*2, "")
+                       );
+                       sayNO; /* cache records failure */
+                   }
+                   ST.cache_offset = offset;
+                   ST.cache_mask   = mask;
+               }
+           }
+
+           /* Prefer B over A for minimal matching. */
+
+           if (cur_curlyx->u.curlyx.minmod) {
+               ST.save_curlyx = cur_curlyx;
+               cur_curlyx = cur_curlyx->u.curlyx.prev_curlyx;
+               ST.cp = regcppush(rex, ST.save_curlyx->u.curlyx.parenfloor);
+               REGCP_SET(ST.lastcp);
+               PUSH_YES_STATE_GOTO(WHILEM_B_min, ST.save_curlyx->u.curlyx.B,
+                                    locinput);
+               assert(0); /* NOTREACHED */
+           }
+
+           /* Prefer A over B for maximal matching. */
+
+           if (n < max) { /* More greed allowed? */
+               ST.cp = regcppush(rex, cur_curlyx->u.curlyx.parenfloor);
+               cur_curlyx->u.curlyx.lastloc = locinput;
+               REGCP_SET(ST.lastcp);
+               PUSH_STATE_GOTO(WHILEM_A_max, A, locinput);
+               assert(0); /* NOTREACHED */
+           }
+           goto do_whilem_B_max;
+       }
+       assert(0); /* NOTREACHED */
+
+       case WHILEM_B_min: /* just matched B in a minimal match */
+       case WHILEM_B_max: /* just matched B in a maximal match */
+           cur_curlyx = ST.save_curlyx;
+           sayYES;
+           assert(0); /* NOTREACHED */
+
+       case WHILEM_B_max_fail: /* just failed to match B in a maximal match */
+           cur_curlyx = ST.save_curlyx;
+           cur_curlyx->u.curlyx.lastloc = ST.save_lastloc;
+           cur_curlyx->u.curlyx.count--;
+           CACHEsayNO;
+           assert(0); /* NOTREACHED */
+
+       case WHILEM_A_min_fail: /* just failed to match A in a minimal match */
+           /* FALL THROUGH */
+       case WHILEM_A_pre_fail: /* just failed to match even minimal A */
+           REGCP_UNWIND(ST.lastcp);
+           regcppop(rex);
+           cur_curlyx->u.curlyx.lastloc = ST.save_lastloc;
+           cur_curlyx->u.curlyx.count--;
+           CACHEsayNO;
+           assert(0); /* NOTREACHED */
+
+       case WHILEM_A_max_fail: /* just failed to match A in a maximal match */
+           REGCP_UNWIND(ST.lastcp);
+           regcppop(rex);      /* Restore some previous $<digit>s? */
+           DEBUG_EXECUTE_r(PerlIO_printf(Perl_debug_log,
+               "%*s  whilem: failed, trying continuation...\n",
+               REPORT_CODE_OFF+depth*2, "")
+           );
+         do_whilem_B_max:
+           if (cur_curlyx->u.curlyx.count >= REG_INFTY
+               && ckWARN(WARN_REGEXP)
+               && !(PL_reg_flags & RF_warned))
+           {
+               PL_reg_flags |= RF_warned;
+               Perl_warner(aTHX_ packWARN(WARN_REGEXP),
+                    "Complex regular subexpression recursion limit (%d) "
+                    "exceeded",
+                    REG_INFTY - 1);
+           }
+
+           /* now try B */
+           ST.save_curlyx = cur_curlyx;
+           cur_curlyx = cur_curlyx->u.curlyx.prev_curlyx;
+           PUSH_YES_STATE_GOTO(WHILEM_B_max, ST.save_curlyx->u.curlyx.B,
+                                locinput);
+           assert(0); /* NOTREACHED */
+
+       case WHILEM_B_min_fail: /* just failed to match B in a minimal match */
+           cur_curlyx = ST.save_curlyx;
+           REGCP_UNWIND(ST.lastcp);
+           regcppop(rex);
+
+           if (cur_curlyx->u.curlyx.count >= /*max*/ARG2(cur_curlyx->u.curlyx.me)) {
+               /* Maximum greed exceeded */
+               if (cur_curlyx->u.curlyx.count >= REG_INFTY
+                   && ckWARN(WARN_REGEXP)
+                   && !(PL_reg_flags & RF_warned))
+               {
+                   PL_reg_flags |= RF_warned;
+                   Perl_warner(aTHX_ packWARN(WARN_REGEXP),
+                       "Complex regular subexpression recursion "
+                       "limit (%d) exceeded",
+                       REG_INFTY - 1);
+               }
+               cur_curlyx->u.curlyx.count--;
+               CACHEsayNO;
+           }
+
+           DEBUG_EXECUTE_r(PerlIO_printf(Perl_debug_log,
+               "%*s  trying longer...\n", REPORT_CODE_OFF+depth*2, "")
+           );
+           /* Try grabbing another A and see if it helps. */
+           cur_curlyx->u.curlyx.lastloc = locinput;
+           ST.cp = regcppush(rex, cur_curlyx->u.curlyx.parenfloor);
+           REGCP_SET(ST.lastcp);
+           PUSH_STATE_GOTO(WHILEM_A_min,
+               /*A*/ NEXTOPER(ST.save_curlyx->u.curlyx.me) + EXTRA_STEP_2ARGS,
+                locinput);
+           assert(0); /* NOTREACHED */
+
+#undef  ST
+#define ST st->u.branch
+
+       case BRANCHJ:       /*  /(...|A|...)/ with long next pointer */
+           next = scan + ARG(scan);
+           if (next == scan)
+               next = NULL;
+           scan = NEXTOPER(scan);
+           /* FALL THROUGH */
+
+       case BRANCH:        /*  /(...|A|...)/ */
+           scan = NEXTOPER(scan); /* scan now points to inner node */
+           ST.lastparen = rex->lastparen;
+           ST.lastcloseparen = rex->lastcloseparen;
+           ST.next_branch = next;
+           REGCP_SET(ST.cp);
+
+           /* Now go into the branch */
+           if (has_cutgroup) {
+               PUSH_YES_STATE_GOTO(BRANCH_next, scan, locinput);
+           } else {
+               PUSH_STATE_GOTO(BRANCH_next, scan, locinput);
+           }
+           assert(0); /* NOTREACHED */
+
+        case CUTGROUP:  /*  /(*THEN)/  */
+            sv_yes_mark = st->u.mark.mark_name = scan->flags ? NULL :
+                MUTABLE_SV(rexi->data->data[ ARG( scan ) ]);
+            PUSH_STATE_GOTO(CUTGROUP_next, next, locinput);
+            assert(0); /* NOTREACHED */
+
+        case CUTGROUP_next_fail:
+            do_cutgroup = 1;
+            no_final = 1;
+            if (st->u.mark.mark_name)
+                sv_commit = st->u.mark.mark_name;
+            sayNO;         
+            assert(0); /* NOTREACHED */
+
+        case BRANCH_next:
+            sayYES;
+            assert(0); /* NOTREACHED */
+
+       case BRANCH_next_fail: /* that branch failed; try the next, if any */
+           if (do_cutgroup) {
+               do_cutgroup = 0;
+               no_final = 0;
+           }
+           REGCP_UNWIND(ST.cp);
+            UNWIND_PAREN(ST.lastparen, ST.lastcloseparen);
+           scan = ST.next_branch;
+           /* no more branches? */
+           if (!scan || (OP(scan) != BRANCH && OP(scan) != BRANCHJ)) {
+               DEBUG_EXECUTE_r({
+                   PerlIO_printf( Perl_debug_log,
+                       "%*s  %sBRANCH failed...%s\n",
+                       REPORT_CODE_OFF+depth*2, "", 
+                       PL_colors[4],
+                       PL_colors[5] );
+               });
+               sayNO_SILENT;
+            }
+           continue; /* execute next BRANCH[J] op */
+           assert(0); /* NOTREACHED */
+    
+       case MINMOD: /* next op will be non-greedy, e.g. A*?  */
+           minmod = 1;
+           break;
+
+#undef  ST
+#define ST st->u.curlym
+
+       case CURLYM:    /* /A{m,n}B/ where A is fixed-length */
+
+           /* This is an optimisation of CURLYX that enables us to push
+            * only a single backtracking state, no matter how many matches
+            * there are in {m,n}. It relies on the pattern being constant
+            * length, with no parens to influence future backrefs
+            */
+
+           ST.me = scan;
+           scan = NEXTOPER(scan) + NODE_STEP_REGNODE;
+
+           ST.lastparen      = rex->lastparen;
+           ST.lastcloseparen = rex->lastcloseparen;
+
+           /* if paren positive, emulate an OPEN/CLOSE around A */
+           if (ST.me->flags) {
+               U32 paren = ST.me->flags;
+               if (paren > PL_regsize)
+                   PL_regsize = paren;
+               scan += NEXT_OFF(scan); /* Skip former OPEN. */
+           }
+           ST.A = scan;
+           ST.B = next;
+           ST.alen = 0;
+           ST.count = 0;
+           ST.minmod = minmod;
+           minmod = 0;
+           ST.c1 = CHRTEST_UNINIT;
+           REGCP_SET(ST.cp);
+
+           if (!(ST.minmod ? ARG1(ST.me) : ARG2(ST.me))) /* min/max */
+               goto curlym_do_B;
+
+         curlym_do_A: /* execute the A in /A{m,n}B/  */
+           PUSH_YES_STATE_GOTO(CURLYM_A, ST.A, locinput); /* match A */
+           assert(0); /* NOTREACHED */
+
+       case CURLYM_A: /* we've just matched an A */
+           ST.count++;
+           /* after first match, determine A's length: u.curlym.alen */
+           if (ST.count == 1) {
+               if (PL_reg_match_utf8) {
+                   char *s = st->locinput;
+                   while (s < locinput) {
+                       ST.alen++;
+                       s += UTF8SKIP(s);
+                   }
+               }
+               else {
+                   ST.alen = locinput - st->locinput;
+               }
+               if (ST.alen == 0)
+                   ST.count = ST.minmod ? ARG1(ST.me) : ARG2(ST.me);
+           }
+           DEBUG_EXECUTE_r(
+               PerlIO_printf(Perl_debug_log,
+                         "%*s  CURLYM now matched %"IVdf" times, len=%"IVdf"...\n",
+                         (int)(REPORT_CODE_OFF+(depth*2)), "",
+                         (IV) ST.count, (IV)ST.alen)
+           );
+
+           if (cur_eval && cur_eval->u.eval.close_paren && 
+               cur_eval->u.eval.close_paren == (U32)ST.me->flags) 
+               goto fake_end;
+               
+           {
+               I32 max = (ST.minmod ? ARG1(ST.me) : ARG2(ST.me));
+               if ( max == REG_INFTY || ST.count < max )
+                   goto curlym_do_A; /* try to match another A */
+           }
+           goto curlym_do_B; /* try to match B */
+
+       case CURLYM_A_fail: /* just failed to match an A */
+           REGCP_UNWIND(ST.cp);
+
+           if (ST.minmod || ST.count < ARG1(ST.me) /* min*/ 
+               || (cur_eval && cur_eval->u.eval.close_paren &&
+                   cur_eval->u.eval.close_paren == (U32)ST.me->flags))
+               sayNO;
+
+         curlym_do_B: /* execute the B in /A{m,n}B/  */
+           if (ST.c1 == CHRTEST_UNINIT) {
+               /* calculate c1 and c2 for possible match of 1st char
+                * following curly */
+               ST.c1 = ST.c2 = CHRTEST_VOID;
+               if (HAS_TEXT(ST.B) || JUMPABLE(ST.B)) {
+                   regnode *text_node = ST.B;
+                   if (! HAS_TEXT(text_node))
+                       FIND_NEXT_IMPT(text_node);
+                   /* this used to be 
+                       
+                       (HAS_TEXT(text_node) && PL_regkind[OP(text_node)] == EXACT)
+                       
+                       But the former is redundant in light of the latter.
+                       
+                       if this changes back then the macro for 
+                       IS_TEXT and friends need to change.
+                    */
+                   if (PL_regkind[OP(text_node)] == EXACT) {
+                        if (! S_setup_EXACTISH_ST_c1_c2(aTHX_
+                           text_node, &ST.c1, ST.c1_utf8, &ST.c2, ST.c2_utf8))
+                        {
+                            sayNO;
+                        }
+                   }
+               }
+           }
+
+           DEBUG_EXECUTE_r(
+               PerlIO_printf(Perl_debug_log,
+                   "%*s  CURLYM trying tail with matches=%"IVdf"...\n",
+                   (int)(REPORT_CODE_OFF+(depth*2)),
+                   "", (IV)ST.count)
+               );
+           if (! NEXTCHR_IS_EOS && ST.c1 != CHRTEST_VOID) {
+                if (! UTF8_IS_INVARIANT(nextchr) && utf8_target) {
+                    if (memNE(locinput, ST.c1_utf8, UTF8SKIP(locinput))
+                        && memNE(locinput, ST.c2_utf8, UTF8SKIP(locinput)))
+                    {
+                        /* simulate B failing */
+                        DEBUG_OPTIMISE_r(
+                            PerlIO_printf(Perl_debug_log,
+                                "%*s  CURLYM Fast bail next target=U+%"UVXf" c1=U+%"UVXf" c2=U+%"UVXf"\n",
+                                (int)(REPORT_CODE_OFF+(depth*2)),"",
+                                valid_utf8_to_uvchr((U8 *) locinput, NULL),
+                                valid_utf8_to_uvchr(ST.c1_utf8, NULL),
+                                valid_utf8_to_uvchr(ST.c2_utf8, NULL))
+                        );
+                        state_num = CURLYM_B_fail;
+                        goto reenter_switch;
+                    }
+                }
+                else if (nextchr != ST.c1 && nextchr != ST.c2) {
+                    /* simulate B failing */
+                    DEBUG_OPTIMISE_r(
+                        PerlIO_printf(Perl_debug_log,
+                            "%*s  CURLYM Fast bail next target=U+%X c1=U+%X c2=U+%X\n",
+                            (int)(REPORT_CODE_OFF+(depth*2)),"",
+                            (int) nextchr, ST.c1, ST.c2)
+                    );
+                    state_num = CURLYM_B_fail;
+                    goto reenter_switch;
+                }
+            }
+
+           if (ST.me->flags) {
+               /* emulate CLOSE: mark current A as captured */
+               I32 paren = ST.me->flags;
+               if (ST.count) {
+                   rex->offs[paren].start
+                       = HOPc(locinput, -ST.alen) - PL_bostr;
+                   rex->offs[paren].end = locinput - PL_bostr;
+                   if ((U32)paren > rex->lastparen)
+                       rex->lastparen = paren;
+                   rex->lastcloseparen = paren;
+               }
+               else
+                   rex->offs[paren].end = -1;
+               if (cur_eval && cur_eval->u.eval.close_paren &&
+                   cur_eval->u.eval.close_paren == (U32)ST.me->flags) 
+               {
+                   if (ST.count) 
+                       goto fake_end;
+                   else
+                       sayNO;
+               }
+           }
+           
+           PUSH_STATE_GOTO(CURLYM_B, ST.B, locinput); /* match B */
+           assert(0); /* NOTREACHED */
+
+       case CURLYM_B_fail: /* just failed to match a B */
+           REGCP_UNWIND(ST.cp);
+            UNWIND_PAREN(ST.lastparen, ST.lastcloseparen);
+           if (ST.minmod) {
+               I32 max = ARG2(ST.me);
+               if (max != REG_INFTY && ST.count == max)
+                   sayNO;
+               goto curlym_do_A; /* try to match a further A */
+           }
+           /* backtrack one A */
+           if (ST.count == ARG1(ST.me) /* min */)
+               sayNO;
+           ST.count--;
+           SET_locinput(HOPc(locinput, -ST.alen));
+           goto curlym_do_B; /* try to match B */
+
+#undef ST
+#define ST st->u.curly
+
+#define CURLY_SETPAREN(paren, success) \
+    if (paren) { \
+       if (success) { \
+           rex->offs[paren].start = HOPc(locinput, -1) - PL_bostr; \
+           rex->offs[paren].end = locinput - PL_bostr; \
+           if (paren > rex->lastparen) \
+               rex->lastparen = paren; \
+           rex->lastcloseparen = paren; \
+       } \
+       else { \
+           rex->offs[paren].end = -1; \
+           rex->lastparen      = ST.lastparen; \
+           rex->lastcloseparen = ST.lastcloseparen; \
+       } \
+    }
+
+        case STAR:             /*  /A*B/ where A is width 1 char */
+           ST.paren = 0;
+           ST.min = 0;
+           ST.max = REG_INFTY;
+           scan = NEXTOPER(scan);
+           goto repeat;
+
+        case PLUS:             /*  /A+B/ where A is width 1 char */
+           ST.paren = 0;
+           ST.min = 1;
+           ST.max = REG_INFTY;
+           scan = NEXTOPER(scan);
+           goto repeat;
+
+       case CURLYN:            /*  /(A){m,n}B/ where A is width 1 char */
+            ST.paren = scan->flags;    /* Which paren to set */
+            ST.lastparen      = rex->lastparen;
+           ST.lastcloseparen = rex->lastcloseparen;
+           if (ST.paren > PL_regsize)
+               PL_regsize = ST.paren;
+           ST.min = ARG1(scan);  /* min to match */
+           ST.max = ARG2(scan);  /* max to match */
+           if (cur_eval && cur_eval->u.eval.close_paren &&
+               cur_eval->u.eval.close_paren == (U32)ST.paren) {
+               ST.min=1;
+               ST.max=1;
+           }
+            scan = regnext(NEXTOPER(scan) + NODE_STEP_REGNODE);
+           goto repeat;
+
+       case CURLY:             /*  /A{m,n}B/ where A is width 1 char */
+           ST.paren = 0;
+           ST.min = ARG1(scan);  /* min to match */
+           ST.max = ARG2(scan);  /* max to match */
+           scan = NEXTOPER(scan) + NODE_STEP_REGNODE;
+         repeat:
+           /*
+           * Lookahead to avoid useless match attempts
+           * when we know what character comes next.
+           *
+           * Used to only do .*x and .*?x, but now it allows
+           * for )'s, ('s and (?{ ... })'s to be in the way
+           * of the quantifier and the EXACT-like node.  -- japhy
+           */
+
+           assert(ST.min <= ST.max);
+            if (! HAS_TEXT(next) && ! JUMPABLE(next)) {
+                ST.c1 = ST.c2 = CHRTEST_VOID;
+            }
+            else {
+               regnode *text_node = next;
+
+               if (! HAS_TEXT(text_node)) 
+                   FIND_NEXT_IMPT(text_node);
+
+               if (! HAS_TEXT(text_node))
+                   ST.c1 = ST.c2 = CHRTEST_VOID;
+               else {
+                   if ( PL_regkind[OP(text_node)] != EXACT ) {
+                       ST.c1 = ST.c2 = CHRTEST_VOID;
+                   }
+                   else {
+                    
+                    /*  Currently we only get here when 
+                        
+                        PL_rekind[OP(text_node)] == EXACT
+                    
+                        if this changes back then the macro for IS_TEXT and 
+                        friends need to change. */
+                        if (! S_setup_EXACTISH_ST_c1_c2(aTHX_
+                           text_node, &ST.c1, ST.c1_utf8, &ST.c2, ST.c2_utf8))
+                        {
+                            sayNO;
+                        }
+                    }
+               }
+           }
+
+           ST.A = scan;
+           ST.B = next;
+           if (minmod) {
+                char *li = locinput;
+               minmod = 0;
+               if (ST.min && regrepeat(rex, &li, ST.A, ST.min, depth) < ST.min)
+                   sayNO;
+                SET_locinput(li);
+               ST.count = ST.min;
+               REGCP_SET(ST.cp);
+               if (ST.c1 == CHRTEST_VOID)
+                   goto curly_try_B_min;
+
+               ST.oldloc = locinput;
+
+               /* set ST.maxpos to the furthest point along the
+                * string that could possibly match */
+               if  (ST.max == REG_INFTY) {
+                   ST.maxpos = PL_regeol - 1;
+                   if (utf8_target)
+                       while (UTF8_IS_CONTINUATION(*(U8*)ST.maxpos))
+                           ST.maxpos--;
+               }
+               else if (utf8_target) {
+                   int m = ST.max - ST.min;
+                   for (ST.maxpos = locinput;
+                        m >0 && ST.maxpos + UTF8SKIP(ST.maxpos) <= PL_regeol; m--)
+                       ST.maxpos += UTF8SKIP(ST.maxpos);
+               }
+               else {
+                   ST.maxpos = locinput + ST.max - ST.min;
+                   if (ST.maxpos >= PL_regeol)
+                       ST.maxpos = PL_regeol - 1;
+               }
+               goto curly_try_B_min_known;
+
+           }
+           else {
+                /* avoid taking address of locinput, so it can remain
+                 * a register var */
+                char *li = locinput;
+               ST.count = regrepeat(rex, &li, ST.A, ST.max, depth);
+               if (ST.count < ST.min)
+                   sayNO;
+                SET_locinput(li);
+               if ((ST.count > ST.min)
+                   && (PL_regkind[OP(ST.B)] == EOL) && (OP(ST.B) != MEOL))
+               {
+                   /* A{m,n} must come at the end of the string, there's
+                    * no point in backing off ... */
+                   ST.min = ST.count;
+                   /* ...except that $ and \Z can match before *and* after
+                      newline at the end.  Consider "\n\n" =~ /\n+\Z\n/.
+                      We may back off by one in this case. */
+                   if (UCHARAT(locinput - 1) == '\n' && OP(ST.B) != EOS)
+                       ST.min--;
+               }
+               REGCP_SET(ST.cp);
+               goto curly_try_B_max;
+           }
+           assert(0); /* NOTREACHED */
+
+
+       case CURLY_B_min_known_fail:
+           /* failed to find B in a non-greedy match where c1,c2 valid */
+
+           REGCP_UNWIND(ST.cp);
+            if (ST.paren) {
+                UNWIND_PAREN(ST.lastparen, ST.lastcloseparen);
+            }
+           /* Couldn't or didn't -- move forward. */
+           ST.oldloc = locinput;
+           if (utf8_target)
+               locinput += UTF8SKIP(locinput);
+           else
+               locinput++;
+           ST.count++;
+         curly_try_B_min_known:
+            /* find the next place where 'B' could work, then call B */
+           {
+               int n;
+               if (utf8_target) {
+                   n = (ST.oldloc == locinput) ? 0 : 1;
+                   if (ST.c1 == ST.c2) {
+                       /* set n to utf8_distance(oldloc, locinput) */
+                       while (locinput <= ST.maxpos
+                              && memNE(locinput, ST.c1_utf8, UTF8SKIP(locinput)))
+                        {
+                           locinput += UTF8SKIP(locinput);
+                           n++;
+                       }
+                   }
+                   else {
+                       /* set n to utf8_distance(oldloc, locinput) */
+                       while (locinput <= ST.maxpos
+                              && memNE(locinput, ST.c1_utf8, UTF8SKIP(locinput))
+                              && memNE(locinput, ST.c2_utf8, UTF8SKIP(locinput)))
+                        {
+                           locinput += UTF8SKIP(locinput);
+                           n++;
+                       }
+                   }
+               }
+               else {  /* Not utf8_target */
+                   if (ST.c1 == ST.c2) {
+                       while (locinput <= ST.maxpos &&
+                              UCHARAT(locinput) != ST.c1)
+                           locinput++;
+                   }
+                   else {
+                       while (locinput <= ST.maxpos
+                              && UCHARAT(locinput) != ST.c1
+                              && UCHARAT(locinput) != ST.c2)
+                           locinput++;
+                   }
+                   n = locinput - ST.oldloc;
+               }
+               if (locinput > ST.maxpos)
+                   sayNO;
+               if (n) {
+                    /* In /a{m,n}b/, ST.oldloc is at "a" x m, locinput is
+                     * at b; check that everything between oldloc and
+                     * locinput matches */
+                    char *li = ST.oldloc;
+                   ST.count += n;
+                   if (regrepeat(rex, &li, ST.A, n, depth) < n)
+                       sayNO;
+                    assert(n == REG_INFTY || locinput == li);
+               }
+               CURLY_SETPAREN(ST.paren, ST.count);
+               if (cur_eval && cur_eval->u.eval.close_paren && 
+                   cur_eval->u.eval.close_paren == (U32)ST.paren) {
+                   goto fake_end;
+               }
+               PUSH_STATE_GOTO(CURLY_B_min_known, ST.B, locinput);
+           }
+           assert(0); /* NOTREACHED */
+
+
+       case CURLY_B_min_fail:
+           /* failed to find B in a non-greedy match where c1,c2 invalid */
+
+           REGCP_UNWIND(ST.cp);
+            if (ST.paren) {
+                UNWIND_PAREN(ST.lastparen, ST.lastcloseparen);
+            }
+           /* failed -- move forward one */
+            {
+                char *li = locinput;
+                if (!regrepeat(rex, &li, ST.A, 1, depth)) {
+                    sayNO;
+                }
+                locinput = li;
+            }
+            {
+               ST.count++;
+               if (ST.count <= ST.max || (ST.max == REG_INFTY &&
+                       ST.count > 0)) /* count overflow ? */
+               {
+                 curly_try_B_min:
+                   CURLY_SETPAREN(ST.paren, ST.count);
+                   if (cur_eval && cur_eval->u.eval.close_paren &&
+                       cur_eval->u.eval.close_paren == (U32)ST.paren) {
+                        goto fake_end;
+                    }
+                   PUSH_STATE_GOTO(CURLY_B_min, ST.B, locinput);
+               }
+           }
+            sayNO;
+           assert(0); /* NOTREACHED */
+
+
+       curly_try_B_max:
+           /* a successful greedy match: now try to match B */
+            if (cur_eval && cur_eval->u.eval.close_paren &&
+                cur_eval->u.eval.close_paren == (U32)ST.paren) {
+                goto fake_end;
+            }
+           {
+               bool could_match = locinput < PL_regeol;
+
+               /* If it could work, try it. */
+                if (ST.c1 != CHRTEST_VOID && could_match) {
+                    if (! UTF8_IS_INVARIANT(UCHARAT(locinput)) && utf8_target)
+                    {
+                        could_match = memEQ(locinput,
+                                            ST.c1_utf8,
+                                            UTF8SKIP(locinput))
+                                    || memEQ(locinput,
+                                             ST.c2_utf8,
+                                             UTF8SKIP(locinput));
+                    }
+                    else {
+                        could_match = UCHARAT(locinput) == ST.c1
+                                      || UCHARAT(locinput) == ST.c2;
+                    }
+                }
+                if (ST.c1 == CHRTEST_VOID || could_match) {
+                   CURLY_SETPAREN(ST.paren, ST.count);
+                   PUSH_STATE_GOTO(CURLY_B_max, ST.B, locinput);
+                   assert(0); /* NOTREACHED */
+               }
+           }
+           /* FALL THROUGH */
+
+       case CURLY_B_max_fail:
+           /* failed to find B in a greedy match */
+
+           REGCP_UNWIND(ST.cp);
+            if (ST.paren) {
+                UNWIND_PAREN(ST.lastparen, ST.lastcloseparen);
+            }
+           /*  back up. */
+           if (--ST.count < ST.min)
+               sayNO;
+           locinput = HOPc(locinput, -1);
+           goto curly_try_B_max;
+
+#undef ST
+
+       case END: /*  last op of main pattern  */
+           fake_end:
+           if (cur_eval) {
+               /* we've just finished A in /(??{A})B/; now continue with B */
+               st->u.eval.toggle_reg_flags
+                           = cur_eval->u.eval.toggle_reg_flags;
+               PL_reg_flags ^= st->u.eval.toggle_reg_flags; 
+
+               st->u.eval.prev_rex = rex_sv;           /* inner */
+               st->u.eval.cp = regcppush(rex, 0); /* Save *all* the positions. */
+               rex_sv = cur_eval->u.eval.prev_rex;
+               SET_reg_curpm(rex_sv);
+               rex = ReANY(rex_sv);
+               rexi = RXi_GET(rex);
+               cur_curlyx = cur_eval->u.eval.prev_curlyx;
+
+               REGCP_SET(st->u.eval.lastcp);
+
+               /* Restore parens of the outer rex without popping the
+                * savestack */
+               S_regcp_restore(aTHX_ rex, cur_eval->u.eval.lastcp);
+
+               st->u.eval.prev_eval = cur_eval;
+               cur_eval = cur_eval->u.eval.prev_eval;
+               DEBUG_EXECUTE_r(
+                   PerlIO_printf(Perl_debug_log, "%*s  EVAL trying tail ... %"UVxf"\n",
+                                     REPORT_CODE_OFF+depth*2, "",PTR2UV(cur_eval)););
+                if ( nochange_depth )
+                   nochange_depth--;
+
+                PUSH_YES_STATE_GOTO(EVAL_AB, st->u.eval.prev_eval->u.eval.B,
+                                    locinput); /* match B */
+           }
+
+           if (locinput < reginfo->till) {
+               DEBUG_EXECUTE_r(PerlIO_printf(Perl_debug_log,
+                                     "%sMatch possible, but length=%ld is smaller than requested=%ld, failing!%s\n",
+                                     PL_colors[4],
+                                     (long)(locinput - PL_reg_starttry),
+                                     (long)(reginfo->till - PL_reg_starttry),
+                                     PL_colors[5]));
+                                                     
+               sayNO_SILENT;           /* Cannot match: too short. */
+           }
+           sayYES;                     /* Success! */
+
+       case SUCCEED: /* successful SUSPEND/UNLESSM/IFMATCH/CURLYM */
+           DEBUG_EXECUTE_r(
+           PerlIO_printf(Perl_debug_log,
+               "%*s  %ssubpattern success...%s\n",
+               REPORT_CODE_OFF+depth*2, "", PL_colors[4], PL_colors[5]));
+           sayYES;                     /* Success! */
+
+#undef  ST
+#define ST st->u.ifmatch
+
+        {
+            char *newstart;
+
+       case SUSPEND:   /* (?>A) */
+           ST.wanted = 1;
+           newstart = locinput;
+           goto do_ifmatch;    
+
+       case UNLESSM:   /* -ve lookaround: (?!A), or with flags, (?<!A) */
+           ST.wanted = 0;
+           goto ifmatch_trivial_fail_test;
+
+       case IFMATCH:   /* +ve lookaround: (?=A), or with flags, (?<=A) */
+           ST.wanted = 1;
+         ifmatch_trivial_fail_test:
+           if (scan->flags) {
+               char * const s = HOPBACKc(locinput, scan->flags);
+               if (!s) {
+                   /* trivial fail */
+                   if (logical) {
+                       logical = 0;
+                       sw = 1 - cBOOL(ST.wanted);
+                   }
+                   else if (ST.wanted)
+                       sayNO;
+                   next = scan + ARG(scan);
+                   if (next == scan)
+                       next = NULL;
+                   break;
+               }
+               newstart = s;
+           }
+           else
+               newstart = locinput;
+
+         do_ifmatch:
+           ST.me = scan;
+           ST.logical = logical;
+           logical = 0; /* XXX: reset state of logical once it has been saved into ST */
+           
+           /* execute body of (?...A) */
+           PUSH_YES_STATE_GOTO(IFMATCH_A, NEXTOPER(NEXTOPER(scan)), newstart);
+           assert(0); /* NOTREACHED */
+        }
+
+       case IFMATCH_A_fail: /* body of (?...A) failed */
+           ST.wanted = !ST.wanted;
+           /* FALL THROUGH */
+
+       case IFMATCH_A: /* body of (?...A) succeeded */
+           if (ST.logical) {
+               sw = cBOOL(ST.wanted);
+           }
+           else if (!ST.wanted)
+               sayNO;
+
+           if (OP(ST.me) != SUSPEND) {
+                /* restore old position except for (?>...) */
+               locinput = st->locinput;
+           }
+           scan = ST.me + ARG(ST.me);
+           if (scan == ST.me)
+               scan = NULL;
+           continue; /* execute B */
+
+#undef ST
+
+       case LONGJMP: /*  alternative with many branches compiles to
+                       * (BRANCHJ; EXACT ...; LONGJMP ) x N */
+           next = scan + ARG(scan);
+           if (next == scan)
+               next = NULL;
+           break;
+
+       case COMMIT:  /*  (*COMMIT)  */
+           reginfo->cutpoint = PL_regeol;
+           /* FALLTHROUGH */
+
+       case PRUNE:   /*  (*PRUNE)   */
+           if (!scan->flags)
+               sv_yes_mark = sv_commit = MUTABLE_SV(rexi->data->data[ ARG( scan ) ]);
+           PUSH_STATE_GOTO(COMMIT_next, next, locinput);
+           assert(0); /* NOTREACHED */
+
+       case COMMIT_next_fail:
+           no_final = 1;    
+           /* FALLTHROUGH */       
+
+       case OPFAIL:   /* (*FAIL)  */
+           sayNO;
+           assert(0); /* NOTREACHED */
+
+#define ST st->u.mark
+        case MARKPOINT: /*  (*MARK:foo)  */
+            ST.prev_mark = mark_state;
+            ST.mark_name = sv_commit = sv_yes_mark 
+                = MUTABLE_SV(rexi->data->data[ ARG( scan ) ]);
+            mark_state = st;
+            ST.mark_loc = locinput;
+            PUSH_YES_STATE_GOTO(MARKPOINT_next, next, locinput);
+            assert(0); /* NOTREACHED */
+
+        case MARKPOINT_next:
+            mark_state = ST.prev_mark;
+            sayYES;
+            assert(0); /* NOTREACHED */
+
+        case MARKPOINT_next_fail:
+            if (popmark && sv_eq(ST.mark_name,popmark)) 
+            {
+                if (ST.mark_loc > startpoint)
+                   reginfo->cutpoint = HOPBACKc(ST.mark_loc, 1);
+                popmark = NULL; /* we found our mark */
+                sv_commit = ST.mark_name;
+
+                DEBUG_EXECUTE_r({
+                        PerlIO_printf(Perl_debug_log,
+                           "%*s  %ssetting cutpoint to mark:%"SVf"...%s\n",
+                           REPORT_CODE_OFF+depth*2, "", 
+                           PL_colors[4], SVfARG(sv_commit), PL_colors[5]);
+               });
+            }
+            mark_state = ST.prev_mark;
+            sv_yes_mark = mark_state ? 
+                mark_state->u.mark.mark_name : NULL;
+            sayNO;
+            assert(0); /* NOTREACHED */
+
+        case SKIP:  /*  (*SKIP)  */
+            if (scan->flags) {
+                /* (*SKIP) : if we fail we cut here*/
+                ST.mark_name = NULL;
+                ST.mark_loc = locinput;
+                PUSH_STATE_GOTO(SKIP_next,next, locinput);
+            } else {
+                /* (*SKIP:NAME) : if there is a (*MARK:NAME) fail where it was, 
+                   otherwise do nothing.  Meaning we need to scan 
+                 */
+                regmatch_state *cur = mark_state;
+                SV *find = MUTABLE_SV(rexi->data->data[ ARG( scan ) ]);
+                
+                while (cur) {
+                    if ( sv_eq( cur->u.mark.mark_name, 
+                                find ) ) 
+                    {
+                        ST.mark_name = find;
+                        PUSH_STATE_GOTO( SKIP_next, next, locinput);
+                    }
+                    cur = cur->u.mark.prev_mark;
+                }
+            }    
+            /* Didn't find our (*MARK:NAME) so ignore this (*SKIP:NAME) */
+            break;    
+
+       case SKIP_next_fail:
+           if (ST.mark_name) {
+               /* (*CUT:NAME) - Set up to search for the name as we 
+                  collapse the stack*/
+               popmark = ST.mark_name;    
+           } else {
+               /* (*CUT) - No name, we cut here.*/
+               if (ST.mark_loc > startpoint)
+                   reginfo->cutpoint = HOPBACKc(ST.mark_loc, 1);
+               /* but we set sv_commit to latest mark_name if there
+                  is one so they can test to see how things lead to this
+                  cut */    
+                if (mark_state) 
+                    sv_commit=mark_state->u.mark.mark_name;                
+            } 
+            no_final = 1; 
+            sayNO;
+            assert(0); /* NOTREACHED */
+#undef ST
+
+        case LNBREAK: /* \R */
+            if ((n=is_LNBREAK_safe(locinput, PL_regeol, utf8_target))) {
+                locinput += n;
+            } else
+                sayNO;
+            break;
+
+#define CASE_CLASS(nAmE)                              \
+        case nAmE:                                    \
+           if (NEXTCHR_IS_EOS)                       \
+               sayNO;                                \
+            if ((n=is_##nAmE(locinput,utf8_target))) {    \
+                locinput += n;                        \
+            } else                                    \
+                sayNO;                                \
+            break;                                    \
+        case N##nAmE:                                 \
+           if (NEXTCHR_IS_EOS)                       \
+               sayNO;                                \
+            if ((n=is_##nAmE(locinput,utf8_target))) {    \
+                sayNO;                                \
+            } else {                                  \
+                locinput += UTF8SKIP(locinput);       \
+            }                                         \
+            break
+
+        CASE_CLASS(VERTWS);  /*  \v \V  */
+        CASE_CLASS(HORIZWS); /*  \h \H  */
+#undef CASE_CLASS
+
+       default:
+           PerlIO_printf(Perl_error_log, "%"UVxf" %d\n",
+                         PTR2UV(scan), OP(scan));
+           Perl_croak(aTHX_ "regexp memory corruption");
+
+        /* this is a point to jump to in order to increment
+         * locinput by one character */
+        increment_locinput:
+            assert(!NEXTCHR_IS_EOS);
+            if (utf8_target) {
+                locinput += PL_utf8skip[nextchr];
+                /* locinput is allowed to go 1 char off the end, but not 2+ */
+                if (locinput > PL_regeol)
+                    sayNO;
+            }
+            else
+                locinput++;
+            break;
+           
+       } /* end switch */ 
+
+        /* switch break jumps here */
+       scan = next; /* prepare to execute the next op and ... */
+       continue;    /* ... jump back to the top, reusing st */
+       assert(0); /* NOTREACHED */
+
+      push_yes_state:
+       /* push a state that backtracks on success */
+       st->u.yes.prev_yes_state = yes_state;
+       yes_state = st;
+       /* FALL THROUGH */
+      push_state:
+       /* push a new regex state, then continue at scan  */
+       {
+           regmatch_state *newst;
+
+           DEBUG_STACK_r({
+               regmatch_state *cur = st;
+               regmatch_state *curyes = yes_state;
+               int curd = depth;
+               regmatch_slab *slab = PL_regmatch_slab;
+                for (;curd > -1;cur--,curd--) {
+                    if (cur < SLAB_FIRST(slab)) {
+                       slab = slab->prev;
+                       cur = SLAB_LAST(slab);
+                    }
+                    PerlIO_printf(Perl_error_log, "%*s#%-3d %-10s %s\n",
+                        REPORT_CODE_OFF + 2 + depth * 2,"",
+                        curd, PL_reg_name[cur->resume_state],
+                        (curyes == cur) ? "yes" : ""
+                    );
+                    if (curyes == cur)
+                       curyes = cur->u.yes.prev_yes_state;
+                }
+            } else 
+                DEBUG_STATE_pp("push")
+            );
+           depth++;
+           st->locinput = locinput;
+           newst = st+1; 
+           if (newst >  SLAB_LAST(PL_regmatch_slab))
+               newst = S_push_slab(aTHX);
+           PL_regmatch_state = newst;
+
+           locinput = pushinput;
+           st = newst;
+           continue;
+           assert(0); /* NOTREACHED */
+       }
+    }
+
+    /*
+    * We get here only if there's trouble -- normally "case END" is
+    * the terminating point.
+    */
+    Perl_croak(aTHX_ "corrupted regexp pointers");
+    /*NOTREACHED*/
+    sayNO;
+
+yes:
+    if (yes_state) {
+       /* we have successfully completed a subexpression, but we must now
+        * pop to the state marked by yes_state and continue from there */
+       assert(st != yes_state);
+#ifdef DEBUGGING
+       while (st != yes_state) {
+           st--;
+           if (st < SLAB_FIRST(PL_regmatch_slab)) {
+               PL_regmatch_slab = PL_regmatch_slab->prev;
+               st = SLAB_LAST(PL_regmatch_slab);
+           }
+           DEBUG_STATE_r({
+               if (no_final) {
+                   DEBUG_STATE_pp("pop (no final)");        
+               } else {
+                   DEBUG_STATE_pp("pop (yes)");
+               }
+           });
+           depth--;
+       }
+#else
+       while (yes_state < SLAB_FIRST(PL_regmatch_slab)
+           || yes_state > SLAB_LAST(PL_regmatch_slab))
+       {
+           /* not in this slab, pop slab */
+           depth -= (st - SLAB_FIRST(PL_regmatch_slab) + 1);
+           PL_regmatch_slab = PL_regmatch_slab->prev;
+           st = SLAB_LAST(PL_regmatch_slab);
+       }
+       depth -= (st - yes_state);
+#endif
+       st = yes_state;
+       yes_state = st->u.yes.prev_yes_state;
+       PL_regmatch_state = st;
+        
+        if (no_final)
+            locinput= st->locinput;
+       state_num = st->resume_state + no_final;
+       goto reenter_switch;
+    }
+
+    DEBUG_EXECUTE_r(PerlIO_printf(Perl_debug_log, "%sMatch successful!%s\n",
+                         PL_colors[4], PL_colors[5]));
+
+    if (PL_reg_state.re_state_eval_setup_done) {
+       /* each successfully executed (?{...}) block does the equivalent of
+        *   local $^R = do {...}
+        * When popping the save stack, all these locals would be undone;
+        * bypass this by setting the outermost saved $^R to the latest
+        * value */
+       if (oreplsv != GvSV(PL_replgv))
+           sv_setsv(oreplsv, GvSV(PL_replgv));
+    }
+    result = 1;
+    goto final_exit;
+
+no:
+    DEBUG_EXECUTE_r(
+       PerlIO_printf(Perl_debug_log,
+            "%*s  %sfailed...%s\n",
+            REPORT_CODE_OFF+depth*2, "", 
+            PL_colors[4], PL_colors[5])
+       );
+
+no_silent:
+    if (no_final) {
+        if (yes_state) {
+            goto yes;
+        } else {
+            goto final_exit;
+        }
+    }    
+    if (depth) {
+       /* there's a previous state to backtrack to */
+       st--;
+       if (st < SLAB_FIRST(PL_regmatch_slab)) {
+           PL_regmatch_slab = PL_regmatch_slab->prev;
+           st = SLAB_LAST(PL_regmatch_slab);
+       }
+       PL_regmatch_state = st;
+       locinput= st->locinput;
+
+       DEBUG_STATE_pp("pop");
+       depth--;
+       if (yes_state == st)
+           yes_state = st->u.yes.prev_yes_state;
+
+       state_num = st->resume_state + 1; /* failure = success + 1 */
+       goto reenter_switch;
+    }
+    result = 0;
+
+  final_exit:
+    if (rex->intflags & PREGf_VERBARG_SEEN) {
+        SV *sv_err = get_sv("REGERROR", 1);
+        SV *sv_mrk = get_sv("REGMARK", 1);
+        if (result) {
+            sv_commit = &PL_sv_no;
+            if (!sv_yes_mark) 
+                sv_yes_mark = &PL_sv_yes;
+        } else {
+            if (!sv_commit) 
+                sv_commit = &PL_sv_yes;
+            sv_yes_mark = &PL_sv_no;
+        }
+        sv_setsv(sv_err, sv_commit);
+        sv_setsv(sv_mrk, sv_yes_mark);
+    }
+
+
+    if (last_pushed_cv) {
+       dSP;
+       POP_MULTICALL;
+        PERL_UNUSED_VAR(SP);
+    }
+
+    /* clean up; in particular, free all slabs above current one */
+    LEAVE_SCOPE(oldsave);
+
+    assert(!result ||  locinput - PL_bostr >= 0);
+    return result ?  locinput - PL_bostr : -1;
+}
+
+/*
+ - regrepeat - repeatedly match something simple, report how many
+ *
+ * What 'simple' means is a node which can be the operand of a quantifier like
+ * '+', or {1,3}
+ *
+ * startposp - pointer a pointer to the start position.  This is updated
+ *             to point to the byte following the highest successful
+ *             match.
+ * p         - the regnode to be repeatedly matched against.
+ * max       - maximum number of things to match.
+ * depth     - (for debugging) backtracking depth.
+ */
+STATIC I32
+S_regrepeat(pTHX_ const regexp *prog, char **startposp, const regnode *p, I32 max, int depth)
+{
+    dVAR;
+    char *scan;     /* Pointer to current position in target string */
+    I32 c;
+    char *loceol = PL_regeol;   /* local version */
+    I32 hardcount = 0;  /* How many matches so far */
+    bool utf8_target = PL_reg_match_utf8;
+    UV utf8_flags;
+#ifndef DEBUGGING
+    PERL_UNUSED_ARG(depth);
+#endif
+
+    PERL_ARGS_ASSERT_REGREPEAT;
+
+    scan = *startposp;
+    if (max == REG_INFTY)
+       max = I32_MAX;
+    else if (! utf8_target && scan + max < loceol)
+       loceol = scan + max;
+
+    /* Here, for the case of a non-UTF-8 target we have adjusted <loceol> down
+     * to the maximum of how far we should go in it (leaving it set to the real
+     * end, if the maximum permissible would take us beyond that).  This allows
+     * us to make the loop exit condition that we haven't gone past <loceol> to
+     * also mean that we haven't exceeded the max permissible count, saving a
+     * test each time through the loop.  But it assumes that the OP matches a
+     * single byte, which is true for most of the OPs below when applied to a
+     * non-UTF-8 target.  Those relatively few OPs that don't have this
+     * characteristic will have to compensate.
+     *
+     * There is no adjustment for UTF-8 targets, as the number of bytes per
+     * character varies.  OPs will have to test both that the count is less
+     * than the max permissible (using <hardcount> to keep track), and that we
+     * are still within the bounds of the string (using <loceol>.  A few OPs
+     * match a single byte no matter what the encoding.  They can omit the max
+     * test if, for the UTF-8 case, they do the adjustment that was skipped
+     * above.
+     *
+     * Thus, the code above sets things up for the common case; and exceptional
+     * cases need extra work; the common case is to make sure <scan> doesn't
+     * go past <loceol>, and for UTF-8 to also use <hardcount> to make sure the
+     * count doesn't exceed the maximum permissible */
+
+    switch (OP(p)) {
+    case REG_ANY:
+       if (utf8_target) {
+           while (scan < loceol && hardcount < max && *scan != '\n') {
+               scan += UTF8SKIP(scan);
+               hardcount++;
+           }
+       } else {
+           while (scan < loceol && *scan != '\n')
+               scan++;
+       }
+       break;
+    case SANY:
+        if (utf8_target) {
+           while (scan < loceol && hardcount < max) {
+               scan += UTF8SKIP(scan);
+               hardcount++;
+           }
+       }
+       else
+           scan = loceol;
+       break;
+    case CANY:  /* Move <scan> forward <max> bytes, unless goes off end */
+        if (utf8_target && scan + max < loceol) {
+
+            /* <loceol> hadn't been adjusted in the UTF-8 case */
+            scan +=  max;
+        }
+        else {
+            scan = loceol;
+        }
+       break;
+    case EXACT:
+        assert(STR_LEN(p) == (UTF_PATTERN) ? UTF8SKIP(STRING(p)) : 1);
+
+       c = (U8)*STRING(p);
+
+        /* Can use a simple loop if the pattern char to match on is invariant
+         * under UTF-8, or both target and pattern aren't UTF-8.  Note that we
+         * can use UTF8_IS_INVARIANT() even if the pattern isn't UTF-8, as it's
+         * true iff it doesn't matter if the argument is in UTF-8 or not */
+        if (UTF8_IS_INVARIANT(c) || (! utf8_target && ! UTF_PATTERN)) {
+            if (utf8_target && scan + max < loceol) {
+                /* We didn't adjust <loceol> because is UTF-8, but ok to do so,
+                 * since here, to match at all, 1 char == 1 byte */
+                loceol = scan + max;
+            }
+           while (scan < loceol && UCHARAT(scan) == c) {
+               scan++;
+           }
+       }
+       else if (UTF_PATTERN) {
+            if (utf8_target) {
+                STRLEN scan_char_len;
+
+                /* When both target and pattern are UTF-8, we have to do
+                 * string EQ */
+                while (hardcount < max
+                       && scan + (scan_char_len = UTF8SKIP(scan)) <= loceol
+                       && scan_char_len <= STR_LEN(p)
+                       && memEQ(scan, STRING(p), scan_char_len))
+                {
+                    scan += scan_char_len;
+                    hardcount++;
+                }
+            }
+            else if (! UTF8_IS_ABOVE_LATIN1(c)) {
+
+                /* Target isn't utf8; convert the character in the UTF-8
+                 * pattern to non-UTF8, and do a simple loop */
+                c = TWO_BYTE_UTF8_TO_UNI(c, *(STRING(p) + 1));
+                while (scan < loceol && UCHARAT(scan) == c) {
+                    scan++;
+                }
+            } /* else pattern char is above Latin1, can't possibly match the
+                 non-UTF-8 target */
+        }
+        else {
+
+            /* Here, the string must be utf8; pattern isn't, and <c> is
+             * different in utf8 than not, so can't compare them directly.
+             * Outside the loop, find the two utf8 bytes that represent c, and
+             * then look for those in sequence in the utf8 string */
+           U8 high = UTF8_TWO_BYTE_HI(c);
+           U8 low = UTF8_TWO_BYTE_LO(c);
+
+           while (hardcount < max
+                   && scan + 1 < loceol
+                   && UCHARAT(scan) == high
+                   && UCHARAT(scan + 1) == low)
+           {
+               scan += 2;
+               hardcount++;
+           }
+       }
+       break;
+
+    case EXACTFA:
+       utf8_flags = FOLDEQ_UTF8_NOMIX_ASCII;
+       goto do_exactf;
+
+    case EXACTFL:
+       PL_reg_flags |= RF_tainted;
+       utf8_flags = FOLDEQ_UTF8_LOCALE;
+       goto do_exactf;
+
+    case EXACTF:
+           utf8_flags = 0;
+           goto do_exactf;
+
+    case EXACTFU_SS:
+    case EXACTFU_TRICKYFOLD:
+    case EXACTFU:
+       utf8_flags = (UTF_PATTERN) ? FOLDEQ_S2_ALREADY_FOLDED : 0;
+
+    do_exactf: {
+        int c1, c2;
+        U8 c1_utf8[UTF8_MAXBYTES+1], c2_utf8[UTF8_MAXBYTES+1];
+
+        assert(STR_LEN(p) == (UTF_PATTERN) ? UTF8SKIP(STRING(p)) : 1);
+
+        if (S_setup_EXACTISH_ST_c1_c2(aTHX_ p, &c1, c1_utf8, &c2, c2_utf8)) {
+            if (c1 == CHRTEST_VOID) {
+                /* Use full Unicode fold matching */
+                char *tmpeol = PL_regeol;
+                STRLEN pat_len = (UTF_PATTERN) ? UTF8SKIP(STRING(p)) : 1;
+                while (hardcount < max
+                        && foldEQ_utf8_flags(scan, &tmpeol, 0, utf8_target,
+                                             STRING(p), NULL, pat_len,
+                                             cBOOL(UTF_PATTERN), utf8_flags))
+                {
+                    scan = tmpeol;
+                    tmpeol = PL_regeol;
+                    hardcount++;
+                }
+            }
+            else if (utf8_target) {
+                if (c1 == c2) {
+                    while (scan < loceol
+                           && hardcount < max
+                           && memEQ(scan, c1_utf8, UTF8SKIP(scan)))
+                    {
+                        scan += UTF8SKIP(scan);
+                        hardcount++;
+                    }
+                }
+                else {
+                    while (scan < loceol
+                           && hardcount < max
+                           && (memEQ(scan, c1_utf8, UTF8SKIP(scan))
+                               || memEQ(scan, c2_utf8, UTF8SKIP(scan))))
+                    {
+                        scan += UTF8SKIP(scan);
+                        hardcount++;
+                    }
+                }
+            }
+            else if (c1 == c2) {
+                while (scan < loceol && UCHARAT(scan) == c1) {
+                    scan++;
+                }
+            }
+            else {
+                while (scan < loceol &&
+                    (UCHARAT(scan) == c1 || UCHARAT(scan) == c2))
+                {
+                    scan++;
+                }
+            }
+       }
+       break;
+    }
+    case ANYOF:
+       if (utf8_target) {
+           STRLEN inclasslen;
+           while (hardcount < max
+                   && scan + (inclasslen = UTF8SKIP(scan)) <= loceol
+                  && reginclass(prog, p, (U8*)scan, utf8_target))
+           {
+               scan += inclasslen;
+               hardcount++;
+           }
+       } else {
+           while (scan < loceol && REGINCLASS(prog, p, (U8*)scan))
+               scan++;
+       }
+       break;
+    case ALNUMU:
+       if (utf8_target) {
+    utf8_wordchar:
+           LOAD_UTF8_CHARCLASS_ALNUM();
+           while (hardcount < max && scan < loceol &&
+                   swash_fetch(PL_utf8_alnum, (U8*)scan, utf8_target))
+            {
+               scan += UTF8SKIP(scan);
+               hardcount++;
+           }
+        } else {
+            while (scan < loceol && isWORDCHAR_L1((U8) *scan)) {
+                scan++;
+            }
+       }
+       break;
+    case ALNUM:
+       if (utf8_target)
+           goto utf8_wordchar;
+       while (scan < loceol && isALNUM((U8) *scan)) {
+           scan++;
+       }
+       break;
+    case ALNUMA:
+        if (utf8_target && scan + max < loceol) {
+
+            /* We didn't adjust <loceol> because is UTF-8, but ok to do so,
+             * since here, to match, 1 char == 1 byte */
+            loceol = scan + max;
+        }
+       while (scan < loceol && isWORDCHAR_A((U8) *scan)) {
+           scan++;
+       }
+       break;
+    case ALNUML:
+       PL_reg_flags |= RF_tainted;
+       if (utf8_target) {
+           while (hardcount < max && scan < loceol &&
+                  isALNUM_LC_utf8((U8*)scan)) {
+               scan += UTF8SKIP(scan);
+               hardcount++;
+           }
+       } else {
+           while (scan < loceol && isALNUM_LC(*scan))
+               scan++;
+       }
+       break;
+    case NALNUMU:
+       if (utf8_target) {
+
+    utf8_Nwordchar:
+
+           LOAD_UTF8_CHARCLASS_ALNUM();
+           while (hardcount < max && scan < loceol &&
+                   ! swash_fetch(PL_utf8_alnum, (U8*)scan, utf8_target))
+            {
+               scan += UTF8SKIP(scan);
+               hardcount++;
+           }
+        } else {
+            while (scan < loceol && ! isWORDCHAR_L1((U8) *scan)) {
+                scan++;
+            }
+       }
+       break;
+    case NALNUM:
+       if (utf8_target)
+           goto utf8_Nwordchar;
+       while (scan < loceol && ! isALNUM((U8) *scan)) {
+           scan++;
+       }
+       break;
+
+    case POSIXA:
+        if (utf8_target && scan + max < loceol) {
+
+            /* We didn't adjust <loceol> because is UTF-8, but ok to do so,
+             * since here, to match, 1 char == 1 byte */
+            loceol = scan + max;
+        }
+        while (scan < loceol && _generic_isCC_A((U8) *scan, FLAGS(p))) {
+           scan++;
+       }
+       break;
+    case NPOSIXA:
+       if (utf8_target) {
+           while (scan < loceol && hardcount < max
+                   && ! _generic_isCC_A((U8) *scan, FLAGS(p)))
+            {
+               scan += UTF8SKIP(scan);
+                hardcount++;
+           }
+       }
+       else {
+           while (scan < loceol && ! _generic_isCC_A((U8) *scan, FLAGS(p))) {
+               scan++;
+           }
+       }
+       break;
+    case NALNUMA:
+       if (utf8_target) {
+           while (scan < loceol && hardcount < max
+                   && ! isWORDCHAR_A((U8) *scan))
+            {
+               scan += UTF8SKIP(scan);
+                hardcount++;
+           }
+       }
+       else {
+           while (scan < loceol && ! isWORDCHAR_A((U8) *scan)) {
+               scan++;
+           }
+       }
+       break;
+    case NALNUML:
+       PL_reg_flags |= RF_tainted;
+       if (utf8_target) {
+           while (hardcount < max && scan < loceol &&
+                  !isALNUM_LC_utf8((U8*)scan)) {
+               scan += UTF8SKIP(scan);
+               hardcount++;
+           }
+       } else {
+           while (scan < loceol && !isALNUM_LC(*scan))
+               scan++;
+       }
+       break;
+    case SPACEU:
+       if (utf8_target) {
+
+    utf8_space:
+
+           while (hardcount < max && scan < loceol
+                   && is_XPERLSPACE_utf8((U8*)scan))
+            {
+               scan += UTF8SKIP(scan);
+               hardcount++;
+           }
+           break;
+       }
+       else {
+            while (scan < loceol && isSPACE_L1((U8) *scan)) {
+                scan++;
+            }
+           break;
+       }
+    case SPACE:
+       if (utf8_target)
+           goto utf8_space;
+
+       while (scan < loceol && isSPACE((U8) *scan)) {
+           scan++;
+       }
+       break;
+    case SPACEA:
+        if (utf8_target && scan + max < loceol) {
+
+            /* We didn't adjust <loceol> because is UTF-8, but ok to do so,
+             * since here, to match, 1 char == 1 byte */
+            loceol = scan + max;
+        }
+       while (scan < loceol && isSPACE_A((U8) *scan)) {
+           scan++;
+       }
+       break;
+    case SPACEL:
+       PL_reg_flags |= RF_tainted;
+       if (utf8_target) {
+           while (hardcount < max && scan < loceol &&
+                  isSPACE_LC_utf8((U8*)scan)) {
+               scan += UTF8SKIP(scan);
+               hardcount++;
+           }
+       } else {
+           while (scan < loceol && isSPACE_LC(*scan))
+               scan++;
+       }
+       break;
+    case NSPACEU:
+       if (utf8_target) {
+
+    utf8_Nspace:
+
+           while (hardcount < max && scan < loceol
+                   && ! is_XPERLSPACE_utf8((U8*)scan))
+            {
+               scan += UTF8SKIP(scan);
+               hardcount++;
+           }
+           break;
+       }
+       else {
+            while (scan < loceol && ! isSPACE_L1((U8) *scan)) {
+                scan++;
+            }
+       }
+       break;
+    case NSPACE:
+       if (utf8_target)
+           goto utf8_Nspace;
+
+       while (scan < loceol && ! isSPACE((U8) *scan)) {
+           scan++;
+       }
+       break;
+    case NSPACEA:
+       if (utf8_target) {
+           while (hardcount < max && scan < loceol
+                  && ! isSPACE_A((U8) *scan))
+            {
+               scan += UTF8SKIP(scan);
+               hardcount++;
+           }
+       }
+       else {
+           while (scan < loceol && ! isSPACE_A((U8) *scan)) {
+               scan++;
+           }
+       }
+       break;
+    case NSPACEL:
+       PL_reg_flags |= RF_tainted;
+       if (utf8_target) {
+           while (hardcount < max && scan < loceol &&
+                  !isSPACE_LC_utf8((U8*)scan)) {
+               scan += UTF8SKIP(scan);
+               hardcount++;
+           }
+       } else {
+           while (scan < loceol && !isSPACE_LC(*scan))
+               scan++;
+       }
+       break;
+    case DIGIT:
+       if (utf8_target) {
+           LOAD_UTF8_CHARCLASS_DIGIT();
+           while (hardcount < max && scan < loceol &&
+                  swash_fetch(PL_utf8_digit, (U8*)scan, utf8_target)) {
+               scan += UTF8SKIP(scan);
+               hardcount++;
+           }
+       } else {
+           while (scan < loceol && isDIGIT(*scan))
+               scan++;
+       }
+       break;
+    case DIGITA:
+        if (utf8_target && scan + max < loceol) {
+
+            /* We didn't adjust <loceol> because is UTF-8, but ok to do so,
+             * since here, to match, 1 char == 1 byte */
+            loceol = scan + max;
+        }
+       while (scan < loceol && isDIGIT_A((U8) *scan)) {
+           scan++;
+       }
+       break;
+    case DIGITL:
+       PL_reg_flags |= RF_tainted;
+       if (utf8_target) {
+           while (hardcount < max && scan < loceol &&
+                  isDIGIT_LC_utf8((U8*)scan)) {
+               scan += UTF8SKIP(scan);
+               hardcount++;
+           }
+       } else {
+           while (scan < loceol && isDIGIT_LC(*scan))
+               scan++;
+       }
+       break;
+    case NDIGIT:
+       if (utf8_target) {
+           LOAD_UTF8_CHARCLASS_DIGIT();
+           while (hardcount < max && scan < loceol &&
+                  !swash_fetch(PL_utf8_digit, (U8*)scan, utf8_target)) {
+               scan += UTF8SKIP(scan);
+               hardcount++;
+           }
+       } else {
+           while (scan < loceol && !isDIGIT(*scan))
+               scan++;
+       }
+       break;
+    case NDIGITA:
+       if (utf8_target) {
+           while (hardcount < max && scan < loceol
+                  && ! isDIGIT_A((U8) *scan)) {
+               scan += UTF8SKIP(scan);
+                hardcount++;
+           }
+       }
+       else {
+           while (scan < loceol && ! isDIGIT_A((U8) *scan)) {
+               scan++;
+           }
+       }
+       break;
+    case NDIGITL:
+       PL_reg_flags |= RF_tainted;
+       if (utf8_target) {
+           while (hardcount < max && scan < loceol &&
+                  !isDIGIT_LC_utf8((U8*)scan)) {
+               scan += UTF8SKIP(scan);
+               hardcount++;
+           }
+       } else {
+           while (scan < loceol && !isDIGIT_LC(*scan))
+               scan++;
+       }
+       break;
+    case LNBREAK:
+        if (utf8_target) {
+           while (hardcount < max && scan < loceol &&
+                    (c=is_LNBREAK_utf8_safe(scan, loceol))) {
+               scan += c;
+               hardcount++;
+           }
+       } else {
+            /* LNBREAK can match one or two latin chars, which is ok, but we
+             * have to use hardcount in this situation, and throw away the
+             * adjustment to <loceol> done before the switch statement */
+            loceol = PL_regeol;
+           while (scan < loceol && (c=is_LNBREAK_latin1_safe(scan, loceol))) {
+               scan+=c;
+               hardcount++;
+           }
+       }
+       break;
+    case HORIZWS:
+        if (utf8_target) {
+           while (hardcount < max && scan < loceol &&
+                    (c=is_HORIZWS_utf8_safe(scan, loceol)))
+            {
+               scan += c;
+               hardcount++;
+           }
+       } else {
+           while (scan < loceol && is_HORIZWS_latin1_safe(scan, loceol)) 
+               scan++;         
+       }       
+       break;
+    case NHORIZWS:
+        if (utf8_target) {
+           while (hardcount < max && scan < loceol &&
+                        !is_HORIZWS_utf8_safe(scan, loceol))
+            {
+               scan += UTF8SKIP(scan);
+               hardcount++;
+           }
+       } else {
+           while (scan < loceol && !is_HORIZWS_latin1_safe(scan, loceol))
+               scan++;
+
+       }       
+       break;
+    case VERTWS:
+        if (utf8_target) {
+           while (hardcount < max && scan < loceol &&
+                            (c=is_VERTWS_utf8_safe(scan, loceol)))
+            {
+               scan += c;
+               hardcount++;
+           }
+       } else {
+           while (scan < loceol && is_VERTWS_latin1_safe(scan, loceol)) 
+               scan++;
+
+       }       
+       break;
+    case NVERTWS:
+        if (utf8_target) {
+           while (hardcount < max && scan < loceol &&
+                                !is_VERTWS_utf8_safe(scan, loceol))
+            {
+               scan += UTF8SKIP(scan);
+               hardcount++;
+           }
+       } else {
+           while (scan < loceol && !is_VERTWS_latin1_safe(scan, loceol)) 
+               scan++;
+          
+       }       
+       break;
+
+    case BOUND:
+    case BOUNDA:
+    case BOUNDL:
+    case BOUNDU:
+    case EOS:
+    case GPOS:
+    case KEEPS:
+    case NBOUND:
+    case NBOUNDA:
+    case NBOUNDL:
+    case NBOUNDU:
+    case OPFAIL:
+    case SBOL:
+    case SEOL:
+        /* These are all 0 width, so match right here or not at all. */
+        break;
+
+    default:
+        Perl_croak(aTHX_ "panic: regrepeat() called with unrecognized node type %d='%s'", OP(p), PL_reg_name[OP(p)]);
+        assert(0); /* NOTREACHED */
+
+    }
+
+    if (hardcount)
+       c = hardcount;
+    else
+       c = scan - *startposp;
+    *startposp = scan;
+
+    DEBUG_r({
+       GET_RE_DEBUG_FLAGS_DECL;
+       DEBUG_EXECUTE_r({
+           SV * const prop = sv_newmortal();
+           regprop(prog, prop, p);
+           PerlIO_printf(Perl_debug_log,
+                       "%*s  %s can match %"IVdf" times out of %"IVdf"...\n",
+                       REPORT_CODE_OFF + depth*2, "", SvPVX_const(prop),(IV)c,(IV)max);
+       });
+    });
+
+    return(c);
+}
+
+
+#if !defined(PERL_IN_XSUB_RE) || defined(PLUGGABLE_RE_EXTENSION)
+/*
+- regclass_swash - prepare the utf8 swash.  Wraps the shared core version to
+create a copy so that changes the caller makes won't change the shared one.
+If <altsvp> is non-null, will return NULL in it, for back-compat.
+ */
+SV *
+Perl_regclass_swash(pTHX_ const regexp *prog, register const regnode* node, bool doinit, SV** listsvp, SV **altsvp)
+{
+    PERL_ARGS_ASSERT_REGCLASS_SWASH;
+
+    if (altsvp) {
+        *altsvp = NULL;
+    }
+
+    return newSVsv(core_regclass_swash(prog, node, doinit, listsvp));
+}
+#endif
+
+STATIC SV *
+S_core_regclass_swash(pTHX_ const regexp *prog, register const regnode* node, bool doinit, SV** listsvp)
+{
+    /* Returns the swash for the input 'node' in the regex 'prog'.
+     * If <doinit> is true, will attempt to create the swash if not already
+     *   done.
+     * If <listsvp> is non-null, will return the swash initialization string in
+     *   it.
+     * Tied intimately to how regcomp.c sets up the data structure */
+
+    dVAR;
+    SV *sw  = NULL;
+    SV *si  = NULL;
+    SV*  invlist = NULL;
+
+    RXi_GET_DECL(prog,progi);
+    const struct reg_data * const data = prog ? progi->data : NULL;
+
+    PERL_ARGS_ASSERT_CORE_REGCLASS_SWASH;
+
+    assert(ANYOF_NONBITMAP(node));
+
+    if (data && data->count) {
+       const U32 n = ARG(node);
+
+       if (data->what[n] == 's') {
+           SV * const rv = MUTABLE_SV(data->data[n]);
+           AV * const av = MUTABLE_AV(SvRV(rv));
+           SV **const ary = AvARRAY(av);
+           U8 swash_init_flags = _CORE_SWASH_INIT_ACCEPT_INVLIST;
+       
+           si = *ary;  /* ary[0] = the string to initialize the swash with */
+
+           /* Elements 2 and 3 are either both present or both absent. [2] is
+            * any inversion list generated at compile time; [3] indicates if
+            * that inversion list has any user-defined properties in it. */
+           if (av_len(av) >= 2) {
+               invlist = ary[2];
+               if (SvUV(ary[3])) {
+                    swash_init_flags |= _CORE_SWASH_INIT_USER_DEFINED_PROPERTY;
+                }
+           }
+           else {
+               invlist = NULL;
+           }
+
+           /* Element [1] is reserved for the set-up swash.  If already there,
+            * return it; if not, create it and store it there */
+           if (SvROK(ary[1])) {
+               sw = ary[1];
+           }
+           else if (si && doinit) {
+
+               sw = _core_swash_init("utf8", /* the utf8 package */
+                                     "", /* nameless */
+                                     si,
+                                     1, /* binary */
+                                     0, /* not from tr/// */
+                                     invlist,
+                                     &swash_init_flags);
+               (void)av_store(av, 1, sw);
+           }
+       }
+    }
+       
+    if (listsvp) {
+       SV* matches_string = newSVpvn("", 0);
+
+       /* Use the swash, if any, which has to have incorporated into it all
+        * possibilities */
+       if ((! sw || (invlist = _get_swash_invlist(sw)) == NULL)
+            && (si && si != &PL_sv_undef))
+        {
+
+           /* If no swash, use the input initialization string, if available */
+           sv_catsv(matches_string, si);
+       }
+
+       /* Add the inversion list to whatever we have.  This may have come from
+        * the swash, or from an input parameter */
+       if (invlist) {
+           sv_catsv(matches_string, _invlist_contents(invlist));
+       }
+       *listsvp = matches_string;
+    }
+
+    return sw;
+}
+
+/*
+ - reginclass - determine if a character falls into a character class
+  n is the ANYOF regnode
+  p is the target string
+  utf8_target tells whether p is in UTF-8.
+
+  Returns true if matched; false otherwise.
+
+  Note that this can be a synthetic start class, a combination of various
+  nodes, so things you think might be mutually exclusive, such as locale,
+  aren't.  It can match both locale and non-locale
+
+ */
+
+STATIC bool
+S_reginclass(pTHX_ const regexp * const prog, register const regnode * const n, register const U8* const p, register const bool utf8_target)
+{
+    dVAR;
+    const char flags = ANYOF_FLAGS(n);
+    bool match = FALSE;
+    UV c = *p;
+
+    PERL_ARGS_ASSERT_REGINCLASS;
+
+    /* If c is not already the code point, get it.  Note that
+     * UTF8_IS_INVARIANT() works even if not in UTF-8 */
+    if (! UTF8_IS_INVARIANT(c) && utf8_target) {
+        STRLEN c_len = 0;
+       c = utf8n_to_uvchr(p, UTF8_MAXBYTES, &c_len,
+               (UTF8_ALLOW_DEFAULT & UTF8_ALLOW_ANYUV)
+               | UTF8_ALLOW_FFFF | UTF8_CHECK_ONLY);
+               /* see [perl #37836] for UTF8_ALLOW_ANYUV; [perl #38293] for
+                * UTF8_ALLOW_FFFF */
+       if (c_len == (STRLEN)-1)
+           Perl_croak(aTHX_ "Malformed UTF-8 character (fatal)");
+    }
+
+    /* If this character is potentially in the bitmap, check it */
+    if (c < 256) {
+       if (ANYOF_BITMAP_TEST(n, c))
+           match = TRUE;
+       else if (flags & ANYOF_NON_UTF8_LATIN1_ALL
+               && ! utf8_target
+               && ! isASCII(c))
+       {
+           match = TRUE;
+       }
+       else if (flags & ANYOF_LOCALE) {
+           PL_reg_flags |= RF_tainted;
+
+           if ((flags & ANYOF_LOC_FOLD)
+                && ANYOF_BITMAP_TEST(n, PL_fold_locale[c]))
+           {
+               match = TRUE;
+           }
+           else if (ANYOF_CLASS_TEST_ANY_SET(n) &&
+                    ((ANYOF_CLASS_TEST(n, ANYOF_ALNUM)   &&  isALNUM_LC(c))  ||
+                     (ANYOF_CLASS_TEST(n, ANYOF_NALNUM)  && !isALNUM_LC(c))  ||
+                     (ANYOF_CLASS_TEST(n, ANYOF_SPACE)   &&  isSPACE_LC(c))  ||
+                     (ANYOF_CLASS_TEST(n, ANYOF_NSPACE)  && !isSPACE_LC(c))  ||
+                     (ANYOF_CLASS_TEST(n, ANYOF_DIGIT)   &&  isDIGIT_LC(c))  ||
+                     (ANYOF_CLASS_TEST(n, ANYOF_NDIGIT)  && !isDIGIT_LC(c))  ||
+                     (ANYOF_CLASS_TEST(n, ANYOF_ALNUMC)  &&  isALNUMC_LC(c)) ||
+                     (ANYOF_CLASS_TEST(n, ANYOF_NALNUMC) && !isALNUMC_LC(c)) ||
+                     (ANYOF_CLASS_TEST(n, ANYOF_ALPHA)   &&  isALPHA_LC(c))  ||
+                     (ANYOF_CLASS_TEST(n, ANYOF_NALPHA)  && !isALPHA_LC(c))  ||
+                     (ANYOF_CLASS_TEST(n, ANYOF_ASCII)   &&  isASCII_LC(c))  ||
+                     (ANYOF_CLASS_TEST(n, ANYOF_NASCII)  && !isASCII_LC(c))  ||
+                     (ANYOF_CLASS_TEST(n, ANYOF_CNTRL)   &&  isCNTRL_LC(c))  ||
+                     (ANYOF_CLASS_TEST(n, ANYOF_NCNTRL)  && !isCNTRL_LC(c))  ||
+                     (ANYOF_CLASS_TEST(n, ANYOF_GRAPH)   &&  isGRAPH_LC(c))  ||
+                     (ANYOF_CLASS_TEST(n, ANYOF_NGRAPH)  && !isGRAPH_LC(c))  ||
+                     (ANYOF_CLASS_TEST(n, ANYOF_LOWER)   &&  isLOWER_LC(c))  ||
+                     (ANYOF_CLASS_TEST(n, ANYOF_NLOWER)  && !isLOWER_LC(c))  ||
+                     (ANYOF_CLASS_TEST(n, ANYOF_PRINT)   &&  isPRINT_LC(c))  ||
+                     (ANYOF_CLASS_TEST(n, ANYOF_NPRINT)  && !isPRINT_LC(c))  ||
+                     (ANYOF_CLASS_TEST(n, ANYOF_PUNCT)   &&  isPUNCT_LC(c))  ||
+                     (ANYOF_CLASS_TEST(n, ANYOF_NPUNCT)  && !isPUNCT_LC(c))  ||
+                     (ANYOF_CLASS_TEST(n, ANYOF_UPPER)   &&  isUPPER_LC(c))  ||
+                     (ANYOF_CLASS_TEST(n, ANYOF_NUPPER)  && !isUPPER_LC(c))  ||
+                     (ANYOF_CLASS_TEST(n, ANYOF_XDIGIT)  &&  isXDIGIT(c))    ||
+                     (ANYOF_CLASS_TEST(n, ANYOF_NXDIGIT) && !isXDIGIT(c))    ||
+                     (ANYOF_CLASS_TEST(n, ANYOF_PSXSPC)  &&  isPSXSPC(c))    ||
+                     (ANYOF_CLASS_TEST(n, ANYOF_NPSXSPC) && !isPSXSPC(c))    ||
+                     (ANYOF_CLASS_TEST(n, ANYOF_BLANK)   &&  isBLANK_LC(c))  ||
+                     (ANYOF_CLASS_TEST(n, ANYOF_NBLANK)  && !isBLANK_LC(c))
+                    ) /* How's that for a conditional? */
+           ) {
+               match = TRUE;
+           }
+       }
+    }
+
+    /* If the bitmap didn't (or couldn't) match, and something outside the
+     * bitmap could match, try that.  Locale nodes specify completely the
+     * behavior of code points in the bit map (otherwise, a utf8 target would
+     * cause them to be treated as Unicode and not locale), except in
+     * the very unlikely event when this node is a synthetic start class, which
+     * could be a combination of locale and non-locale nodes.  So allow locale
+     * to match for the synthetic start class, which will give a false
+     * positive that will be resolved when the match is done again as not part
+     * of the synthetic start class */
+    if (!match) {
+       if (utf8_target && (flags & ANYOF_UNICODE_ALL) && c >= 256) {
+           match = TRUE;       /* Everything above 255 matches */
+       }
+       else if (ANYOF_NONBITMAP(n)
+                && ((flags & ANYOF_NONBITMAP_NON_UTF8)
+                    || (utf8_target
+                        && (c >=256
+                            || (! (flags & ANYOF_LOCALE))
+                            || (flags & ANYOF_IS_SYNTHETIC)))))
+       {
+           SV * const sw = core_regclass_swash(prog, n, TRUE, 0);
+           if (sw) {
+               U8 * utf8_p;
+               if (utf8_target) {
+                   utf8_p = (U8 *) p;
+               } else { /* Convert to utf8 */
+                   STRLEN len = 1;
+                   utf8_p = bytes_to_utf8(p, &len);
+               }
+
+               if (swash_fetch(sw, utf8_p, TRUE)) {
+                   match = TRUE;
+                }
+
+               /* If we allocated a string above, free it */
+               if (! utf8_target) Safefree(utf8_p);
+           }
+       }
+
+        if (UNICODE_IS_SUPER(c)
+            && (flags & ANYOF_WARN_SUPER)
+            && ckWARN_d(WARN_NON_UNICODE))
+        {
+            Perl_warner(aTHX_ packWARN(WARN_NON_UNICODE),
+                "Code point 0x%04"UVXf" is not Unicode, all \\p{} matches fail; all \\P{} matches succeed", c);
+        }
+    }
+
+    /* The xor complements the return if to invert: 1^1 = 0, 1^0 = 1 */
+    return cBOOL(flags & ANYOF_INVERT) ^ match;
+}
+
+STATIC U8 *
+S_reghop3(U8 *s, I32 off, const U8* lim)
+{
+    /* return the position 'off' UTF-8 characters away from 's', forward if
+     * 'off' >= 0, backwards if negative.  But don't go outside of position
+     * 'lim', which better be < s  if off < 0 */
+
+    dVAR;
+
+    PERL_ARGS_ASSERT_REGHOP3;
+
+    if (off >= 0) {
+       while (off-- && s < lim) {
+           /* XXX could check well-formedness here */
+           s += UTF8SKIP(s);
+       }
+    }
+    else {
+        while (off++ && s > lim) {
+            s--;
+            if (UTF8_IS_CONTINUED(*s)) {
+                while (s > lim && UTF8_IS_CONTINUATION(*s))
+                    s--;
+           }
+            /* XXX could check well-formedness here */
+       }
+    }
+    return s;
+}
+
+#ifdef XXX_dmq
+/* there are a bunch of places where we use two reghop3's that should
+   be replaced with this routine. but since thats not done yet 
+   we ifdef it out - dmq
+*/
+STATIC U8 *
+S_reghop4(U8 *s, I32 off, const U8* llim, const U8* rlim)
+{
+    dVAR;
+
+    PERL_ARGS_ASSERT_REGHOP4;
+
+    if (off >= 0) {
+        while (off-- && s < rlim) {
+            /* XXX could check well-formedness here */
+            s += UTF8SKIP(s);
+        }
+    }
+    else {
+        while (off++ && s > llim) {
+            s--;
+            if (UTF8_IS_CONTINUED(*s)) {
+                while (s > llim && UTF8_IS_CONTINUATION(*s))
+                    s--;
+            }
+            /* XXX could check well-formedness here */
+        }
+    }
+    return s;
+}
+#endif
+
+STATIC U8 *
+S_reghopmaybe3(U8* s, I32 off, const U8* lim)
+{
+    dVAR;
+
+    PERL_ARGS_ASSERT_REGHOPMAYBE3;
+
+    if (off >= 0) {
+       while (off-- && s < lim) {
+           /* XXX could check well-formedness here */
+           s += UTF8SKIP(s);
+       }
+       if (off >= 0)
+           return NULL;
+    }
+    else {
+        while (off++ && s > lim) {
+            s--;
+            if (UTF8_IS_CONTINUED(*s)) {
+                while (s > lim && UTF8_IS_CONTINUATION(*s))
+                    s--;
+           }
+            /* XXX could check well-formedness here */
+       }
+       if (off <= 0)
+           return NULL;
+    }
+    return s;
+}
+
+static void
+restore_pos(pTHX_ void *arg)
+{
+    dVAR;
+    regexp * const rex = (regexp *)arg;
+    if (PL_reg_state.re_state_eval_setup_done) {
+       if (PL_reg_oldsaved) {
+           rex->subbeg = PL_reg_oldsaved;
+           rex->sublen = PL_reg_oldsavedlen;
+           rex->suboffset = PL_reg_oldsavedoffset;
+           rex->subcoffset = PL_reg_oldsavedcoffset;
+#ifdef PERL_OLD_COPY_ON_WRITE
+           rex->saved_copy = PL_nrs;
+#endif
+           RXp_MATCH_COPIED_on(rex);
+       }
+       PL_reg_magic->mg_len = PL_reg_oldpos;
+       PL_reg_state.re_state_eval_setup_done = FALSE;
+       PL_curpm = PL_reg_oldcurpm;
+    }  
+}
+
+STATIC void
+S_to_utf8_substr(pTHX_ register regexp *prog)
+{
+    /* Converts substr fields in prog from bytes to UTF-8, calling fbm_compile
+     * on the converted value */
+
+    int i = 1;
+
+    PERL_ARGS_ASSERT_TO_UTF8_SUBSTR;
+
+    do {
+       if (prog->substrs->data[i].substr
+           && !prog->substrs->data[i].utf8_substr) {
+           SV* const sv = newSVsv(prog->substrs->data[i].substr);
+           prog->substrs->data[i].utf8_substr = sv;
+           sv_utf8_upgrade(sv);
+           if (SvVALID(prog->substrs->data[i].substr)) {
+               if (SvTAIL(prog->substrs->data[i].substr)) {
+                   /* Trim the trailing \n that fbm_compile added last
+                      time.  */
+                   SvCUR_set(sv, SvCUR(sv) - 1);
+                   /* Whilst this makes the SV technically "invalid" (as its
+                      buffer is no longer followed by "\0") when fbm_compile()
+                      adds the "\n" back, a "\0" is restored.  */
+                   fbm_compile(sv, FBMcf_TAIL);
+               } else
+                   fbm_compile(sv, 0);
+           }
+           if (prog->substrs->data[i].substr == prog->check_substr)
+               prog->check_utf8 = sv;
+       }
+    } while (i--);
+}
+
+STATIC bool
+S_to_byte_substr(pTHX_ register regexp *prog)
+{
+    /* Converts substr fields in prog from UTF-8 to bytes, calling fbm_compile
+     * on the converted value; returns FALSE if can't be converted. */
+
+    dVAR;
+    int i = 1;
+
+    PERL_ARGS_ASSERT_TO_BYTE_SUBSTR;
+
+    do {
+       if (prog->substrs->data[i].utf8_substr
+           && !prog->substrs->data[i].substr) {
+           SV* sv = newSVsv(prog->substrs->data[i].utf8_substr);
+           if (! sv_utf8_downgrade(sv, TRUE)) {
+                return FALSE;
+            }
+            if (SvVALID(prog->substrs->data[i].utf8_substr)) {
+                if (SvTAIL(prog->substrs->data[i].utf8_substr)) {
+                    /* Trim the trailing \n that fbm_compile added last
+                        time.  */
+                    SvCUR_set(sv, SvCUR(sv) - 1);
+                    fbm_compile(sv, FBMcf_TAIL);
+                } else
+                    fbm_compile(sv, 0);
+            }
+           prog->substrs->data[i].substr = sv;
+           if (prog->substrs->data[i].utf8_substr == prog->check_utf8)
+               prog->check_substr = sv;
+       }
+    } while (i--);
+
+    return TRUE;
+}
+
+/* These constants are for finding GCB=LV and GCB=LVT.  These are for the
+ * pre-composed Hangul syllables, which are all in a contiguous block and
+ * arranged there in such a way so as to facilitate alorithmic determination of
+ * their characteristics.  As such, they don't need a swash, but can be
+ * determined by simple arithmetic.  Almost all are GCB=LVT, but every 28th one
+ * is a GCB=LV */
+#define SBASE 0xAC00    /* Start of block */
+#define SCount 11172    /* Length of block */
+#define TCount 28
+
+#if 0   /* This routine is not currently used */
+PERL_STATIC_INLINE bool
+S_is_utf8_X_LV(pTHX_ const U8 *p)
+{
+    /* Unlike most other similarly named routines here, this does not create a
+     * swash, so swash_fetch() cannot be used on PL_utf8_X_LV. */
+
+    dVAR;
+
+    UV cp = valid_utf8_to_uvchr(p, NULL);
+
+    PERL_ARGS_ASSERT_IS_UTF8_X_LV;
+
+    /* The earliest Unicode releases did not have these precomposed Hangul
+     * syllables.  Set to point to undef in that case, so will return false on
+     * every call */
+    if (! PL_utf8_X_LV) {   /* Set up if this is the first time called */
+        PL_utf8_X_LV = swash_init("utf8", "_X_GCB_LV", &PL_sv_undef, 1, 0);
+        if (_invlist_len(_get_swash_invlist(PL_utf8_X_LV)) == 0) {
+            SvREFCNT_dec(PL_utf8_X_LV);
+            PL_utf8_X_LV = &PL_sv_undef;
+        }
+    }
+
+    return (PL_utf8_X_LV != &PL_sv_undef
+            && cp >= SBASE && cp < SBASE + SCount
+            && (cp - SBASE) % TCount == 0); /* Only every TCount one is LV */
+}
+#endif
+
+PERL_STATIC_INLINE bool
+S_is_utf8_X_LVT(pTHX_ const U8 *p)
+{
+    /* Unlike most other similarly named routines here, this does not create a
+     * swash, so swash_fetch() cannot be used on PL_utf8_X_LVT. */
+
+    dVAR;
+
+    UV cp = valid_utf8_to_uvchr(p, NULL);
+
+    PERL_ARGS_ASSERT_IS_UTF8_X_LVT;
+
+    /* The earliest Unicode releases did not have these precomposed Hangul
+     * syllables.  Set to point to undef in that case, so will return false on
+     * every call */
+    if (! PL_utf8_X_LVT) {   /* Set up if this is the first time called */
+        PL_utf8_X_LVT = swash_init("utf8", "_X_GCB_LVT", &PL_sv_undef, 1, 0);
+        if (_invlist_len(_get_swash_invlist(PL_utf8_X_LVT)) == 0) {
+            SvREFCNT_dec(PL_utf8_X_LVT);
+            PL_utf8_X_LVT = &PL_sv_undef;
+        }
+    }
+
+    return (PL_utf8_X_LVT != &PL_sv_undef
+            && cp >= SBASE && cp < SBASE + SCount
+            && (cp - SBASE) % TCount != 0); /* All but every TCount one is LV */
+}
+
+/*
+ * Local variables:
+ * c-indentation-style: bsd
+ * c-basic-offset: 4
+ * indent-tabs-mode: nil
+ * End:
+ *
+ * ex: set ts=8 sts=4 sw=4 et:
+ */