This is a live mirror of the Perl 5 development currently hosted at https://github.com/perl/perl5
Fix a memory leak :
[perl5.git] / regexec.c
index 79254eb..60ec4ff 100644 (file)
--- a/regexec.c
+++ b/regexec.c
@@ -13,7 +13,6 @@
  * 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
 */
 
 #ifdef PERL_EXT_RE_BUILD
-/* need to replace pregcomp et al, so enable that */
-#  ifndef PERL_IN_XSUB_RE
-#    define PERL_IN_XSUB_RE
-#  endif
-/* need access to debugger hooks */
-#  if defined(PERL_EXT_RE_DEBUG) && !defined(DEBUGGING)
-#    define DEBUGGING
-#  endif
-#endif
-
-#ifdef PERL_IN_XSUB_RE
-/* We *really* need to overwrite these symbols: */
-#  define Perl_regexec_flags my_regexec
-#  define Perl_regdump my_regdump
-#  define Perl_regprop my_regprop
-#  define Perl_re_intuit_start my_re_intuit_start
-/* *These* symbols are masked to allow static link. */
-#  define Perl_pregexec my_pregexec
-#  define Perl_reginitcolors my_reginitcolors
-#  define Perl_regclass_swash my_regclass_swash
-
-#  define PERL_NO_GET_CONTEXT
+#include "re_top.h"
 #endif
 
 /*
 #define PERL_IN_REGEXEC_C
 #include "perl.h"
 
-#include "regcomp.h"
+#ifdef PERL_IN_XSUB_RE
+#  include "re_comp.h"
+#else
+#  include "regcomp.h"
+#endif
 
 #define RF_tainted     1               /* tainted information used? */
 #define RF_warned      2               /* warned about big count? */
-#define RF_evaled      4               /* Did an EVAL with setting? */
-#define RF_utf8                8               /* String contains multibyte chars? */
+
+#define RF_utf8                8               /* Pattern contains multibyte chars? */
 
 #define UTF ((PL_reg_flags & RF_utf8) != 0)
 
 #define        STATIC  static
 #endif
 
-#define REGINCLASS(p,c)  (ANYOF_FLAGS(p) ? reginclass(p,c,0,0) : ANYOF_BITMAP_TEST(p,*(c)))
+#define REGINCLASS(prog,p,c)  (ANYOF_FLAGS(p) ? reginclass(prog,p,c,0,0) : ANYOF_BITMAP_TEST(p,*(c)))
 
 /*
  * Forwards.
 #define CHR_SVLEN(sv) (do_utf8 ? sv_len_utf8(sv) : SvCUR(sv))
 #define CHR_DIST(a,b) (PL_reg_match_utf8 ? utf8_distance(a,b) : a - b)
 
-#define reghop_c(pos,off) ((char*)reghop((U8*)pos, off))
-#define reghopmaybe_c(pos,off) ((char*)reghopmaybe((U8*)pos, off))
-#define HOP(pos,off) (PL_reg_match_utf8 ? reghop((U8*)pos, off) : (U8*)(pos + off))
-#define HOPMAYBE(pos,off) (PL_reg_match_utf8 ? reghopmaybe((U8*)pos, off) : (U8*)(pos + off))
-#define HOPc(pos,off) ((char*)HOP(pos,off))
-#define HOPMAYBEc(pos,off) ((char*)HOPMAYBE(pos,off))
-
-#define HOPBACK(pos, off) (            \
-    (PL_reg_match_utf8)                        \
-       ? reghopmaybe((U8*)pos, -off)   \
-    : (pos - off >= PL_bostr)          \
-       ? (U8*)(pos - off)              \
-    : (U8*)NULL                                \
-)
-#define HOPBACKc(pos, off) (char*)HOPBACK(pos, off)
-
-#define reghop3_c(pos,off,lim) ((char*)reghop3((U8*)pos, off, (U8*)lim))
-#define reghopmaybe3_c(pos,off,lim) ((char*)reghopmaybe3((U8*)pos, off, (U8*)lim))
-#define HOP3(pos,off,lim) (PL_reg_match_utf8 ? reghop3((U8*)pos, off, (U8*)lim) : (U8*)(pos + off))
-#define HOPMAYBE3(pos,off,lim) (PL_reg_match_utf8 ? reghopmaybe3((U8*)pos, off, (U8*)lim) : (U8*)(pos + off))
+#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 HOPMAYBE3c(pos,off,lim) ((char*)HOPMAYBE3(pos,off,lim))
 
 #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); assert(ok); LEAVE; } } STMT_END
 #define LOAD_UTF8_CHARCLASS_SPACE() LOAD_UTF8_CHARCLASS(space," ")
 #define LOAD_UTF8_CHARCLASS_MARK()  LOAD_UTF8_CHARCLASS(mark, "\xcd\x86")
 
+/* TODO: Combine JUMPABLE and HAS_TEXT to cache OP(rn) */
+
 /* for use after a quantifier and before an EXACT-like node -- japhy */
 #define JUMPABLE(rn) ( \
     OP(rn) == OPEN || OP(rn) == CLOSE || OP(rn) == EVAL || \
     OP(rn) == SUSPEND || OP(rn) == IFMATCH || \
     OP(rn) == PLUS || OP(rn) == MINMOD || \
-    (PL_regkind[(U8)OP(rn)] == CURLY && ARG1(rn) > 0) \
+    (PL_regkind[OP(rn)] == CURLY && ARG1(rn) > 0) \
 )
 
 #define HAS_TEXT(rn) ( \
-    PL_regkind[(U8)OP(rn)] == EXACT || PL_regkind[(U8)OP(rn)] == REF \
+    PL_regkind[OP(rn)] == EXACT || PL_regkind[OP(rn)] == REF \
 )
 
 /*
   follow but for lookbehind (rn->flags != 0) we skip to the next step.
 */
 #define FIND_NEXT_IMPT(rn) STMT_START { \
-    while (JUMPABLE(rn)) \
-       if (OP(rn) == SUSPEND || PL_regkind[(U8)OP(rn)] == CURLY) \
+    while (JUMPABLE(rn)) { \
+       const OPCODE type = OP(rn); \
+       if (type == SUSPEND || PL_regkind[type] == CURLY) \
            rn = NEXTOPER(NEXTOPER(rn)); \
-       else if (OP(rn) == PLUS) \
+       else if (type == PLUS) \
            rn = NEXTOPER(rn); \
-       else if (OP(rn) == IFMATCH) \
+       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);
 
 STATIC CHECKPOINT
@@ -183,11 +161,12 @@ S_regcppush(pTHX_ I32 parenfloor)
 #define REGCP_PAREN_ELEMS 4
     const int paren_elems_to_push = (PL_regsize - parenfloor) * REGCP_PAREN_ELEMS;
     int p;
+    GET_RE_DEBUG_FLAGS_DECL;
 
     if (paren_elems_to_push < 0)
        Perl_croak(aTHX_ "panic: paren_elems_to_push < 0");
 
-#define REGCP_OTHER_ELEMS 6
+#define REGCP_OTHER_ELEMS 8
     SSGROW(paren_elems_to_push + REGCP_OTHER_ELEMS);
     for (p = PL_regsize; p > parenfloor; p--) {
 /* REGCP_PARENS_ELEMS are pushed per pairs of parentheses. */
@@ -195,8 +174,16 @@ S_regcppush(pTHX_ I32 parenfloor)
        SSPUSHINT(PL_regstartp[p]);
        SSPUSHPTR(PL_reg_start_tmp[p]);
        SSPUSHINT(p);
+       DEBUG_EXECUTE_r(PerlIO_printf(Perl_debug_log,
+         "     saving \\%"UVuf" %"IVdf"(%"IVdf")..%"IVdf"\n",
+                     (UV)p, (IV)PL_regstartp[p],
+                     (IV)(PL_reg_start_tmp[p] - PL_bostr),
+                     (IV)PL_regendp[p]
+       ));
     }
 /* REGCP_OTHER_ELEMS are pushed in any case, parentheses or no. */
+    SSPUSHPTR(PL_regstartp);
+    SSPUSHPTR(PL_regendp);
     SSPUSHINT(PL_regsize);
     SSPUSHINT(*PL_reglastparen);
     SSPUSHINT(*PL_reglastcloseparen);
@@ -211,21 +198,26 @@ S_regcppush(pTHX_ I32 parenfloor)
 }
 
 /* These are needed since we do not localize EVAL nodes: */
-#  define REGCP_SET(cp)  DEBUG_EXECUTE_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_EXECUTE_r(cp != PL_savestack_ix ?            \
-                               PerlIO_printf(Perl_debug_log,           \
-                               "  Clearing an EVAL scope, savestack=%"IVdf"..%"IVdf"\n", \
-                               (IV)(cp), (IV)PL_savestack_ix) : 0); regcpblow(cp)
+#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)
 
 STATIC char *
-S_regcppop(pTHX)
+S_regcppop(pTHX_ const regexp *rex)
 {
     dVAR;
     I32 i;
-    U32 paren = 0;
     char *input;
 
     GET_RE_DEBUG_FLAGS_DECL;
@@ -238,12 +230,15 @@ S_regcppop(pTHX)
     *PL_reglastcloseparen = SSPOPINT;
     *PL_reglastparen = SSPOPINT;
     PL_regsize = SSPOPINT;
+    PL_regendp=(I32 *) SSPOPPTR;
+    PL_regstartp=(I32 *) SSPOPPTR;
 
+    
     /* Now restore the parentheses context. */
     for (i -= (REGCP_OTHER_ELEMS - REGCP_FRAME_ELEMS);
         i > 0; i -= REGCP_PAREN_ELEMS) {
        I32 tmps;
-       paren = (U32)SSPOPINT;
+       U32 paren = (U32)SSPOPINT;
        PL_reg_start_tmp[paren] = (char *) SSPOPPTR;
        PL_regstartp[paren] = SSPOPINT;
        tmps = SSPOPINT;
@@ -259,10 +254,10 @@ S_regcppop(pTHX)
        );
     }
     DEBUG_EXECUTE_r(
-       if ((I32)(*PL_reglastparen + 1) <= PL_regnpar) {
+       if (*PL_reglastparen + 1 <= rex->nparens) {
            PerlIO_printf(Perl_debug_log,
                          "     restoring \\%"IVdf"..\\%"IVdf" to undef\n",
-                         (IV)(*PL_reglastparen + 1), (IV)PL_regnpar);
+                         (IV)(*PL_reglastparen + 1), (IV)rex->nparens);
        }
     );
 #if 1
@@ -276,47 +271,22 @@ S_regcppop(pTHX)
      * building DynaLoader will fail:
      * "Error: '*' not in typemap in DynaLoader.xs, line 164"
      * --jhi */
-    for (paren = *PL_reglastparen + 1; (I32)paren <= PL_regnpar; paren++) {
-       if ((I32)paren > PL_regsize)
-           PL_regstartp[paren] = -1;
-       PL_regendp[paren] = -1;
+    for (i = *PL_reglastparen + 1; (U32)i <= rex->nparens; i++) {
+       if (i > PL_regsize)
+           PL_regstartp[i] = -1;
+       PL_regendp[i] = -1;
     }
 #endif
     return input;
 }
 
-typedef struct re_cc_state
-{
-    I32 ss;
-    regnode *node;
-    struct re_cc_state *prev;
-    CURCUR *cc;
-    regexp *re;
-} re_cc_state;
-
 #define regcpblow(cp) LEAVE_SCOPE(cp)  /* Ignores regcppush()ed data. */
 
-#define TRYPAREN(paren, n, input, where) {                     \
-    if (paren) {                                               \
-       if (n) {                                                \
-           PL_regstartp[paren] = HOPc(input, -1) - PL_bostr;   \
-           PL_regendp[paren] = input - PL_bostr;               \
-       }                                                       \
-       else                                                    \
-           PL_regendp[paren] = -1;                             \
-    }                                                          \
-    REGMATCH(next, where);                                     \
-    if (result)                                                        \
-       sayYES;                                                 \
-    if (paren && n)                                            \
-       PL_regendp[paren] = -1;                                 \
-}
-
-
 /*
  * pregexec and friends
  */
 
+#ifndef PERL_IN_XSUB_RE
 /*
  - pregexec - match a regexp against a string
  */
@@ -332,19 +302,7 @@ Perl_pregexec(pTHX_ register regexp *prog, char *stringarg, register char *stren
        regexec_flags(prog, stringarg, strend, strbeg, minend, screamer, NULL,
                      nosave ? 0 : REXEC_COPY_STR);
 }
-
-STATIC void
-S_cache_re(pTHX_ regexp *prog)
-{
-    dVAR;
-    PL_regprecomp = prog->precomp;             /* Needed for FAIL. */
-#ifdef DEBUGGING
-    PL_regprogram = prog->program;
 #endif
-    PL_regnpar = prog->nparens;
-    PL_regdata = prog->data;
-    PL_reg_re = prog;
-}
 
 /*
  * Need to implement the following flags for reg_anch:
@@ -404,14 +362,13 @@ Perl_re_intuit_start(pTHX_ regexp *prog, SV *sv, char *strpos,
     register SV *check;
     char *strbeg;
     char *t;
-    const int do_utf8 = sv ? SvUTF8(sv) : 0;   /* if no sv we have to assume bytes */
+    const bool do_utf8 = (sv && SvUTF8(sv)) ? 1 : 0; /* if no sv we have to assume bytes */
     I32 ml_anch;
     register char *other_last = NULL;  /* other substr checked before this */
     char *check_at = NULL;             /* check substr found at this pos */
     const I32 multiline = prog->reganch & PMf_MULTILINE;
 #ifdef DEBUGGING
     const char * const i_strpos = strpos;
-    SV * const dsv = PERL_DEBUG_PAD_ZERO(0);
 #endif
 
     GET_RE_DEBUG_FLAGS_DECL;
@@ -419,34 +376,13 @@ Perl_re_intuit_start(pTHX_ regexp *prog, SV *sv, char *strpos,
     RX_MATCH_UTF8_set(prog,do_utf8);
 
     if (prog->reganch & ROPT_UTF8) {
-       DEBUG_EXECUTE_r(PerlIO_printf(Perl_debug_log,
-                             "UTF-8 regex...\n"));
        PL_reg_flags |= RF_utf8;
     }
-
-    DEBUG_EXECUTE_r({
-        const char *s   = PL_reg_match_utf8 ?
-                        sv_uni_display(dsv, sv, 60, UNI_DISPLAY_REGEX) :
-                        strpos;
-        const int   len = PL_reg_match_utf8 ?
-                        strlen(s) : strend - strpos;
-        if (!PL_colorset)
-             reginitcolors();
-        if (PL_reg_match_utf8)
-            DEBUG_EXECUTE_r(PerlIO_printf(Perl_debug_log,
-                                  "UTF-8 target...\n"));
-        PerlIO_printf(Perl_debug_log,
-                      "%sGuessing start of match, REx%s \"%s%.60s%s%s\" against \"%s%.*s%s%s\"...\n",
-                      PL_colors[4], PL_colors[5], PL_colors[0],
-                      prog->precomp,
-                      PL_colors[1],
-                      (strlen(prog->precomp) > 60 ? "..." : ""),
-                      PL_colors[0],
-                      (int)(len > 60 ? 60 : len),
-                      s, PL_colors[1],
-                      (len > 60 ? "..." : "")
+    DEBUG_EXECUTE_r( 
+        debug_start_match(prog, do_utf8, 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) {
@@ -454,6 +390,7 @@ Perl_re_intuit_start(pTHX_ regexp *prog, SV *sv, char *strpos,
                              "String too short... [re_intuit_start]\n"));
        goto fail;
     }
+                
     strbeg = (sv && SvPOK(sv)) ? strend - SvCUR(sv) : strpos;
     PL_regeol = strend;
     if (do_utf8) {
@@ -465,9 +402,9 @@ Perl_re_intuit_start(pTHX_ regexp *prog, SV *sv, char *strpos,
            to_byte_substr(prog);
        check = prog->check_substr;
     }
-   if (check == &PL_sv_undef) {
+    if (check == &PL_sv_undef) {
        DEBUG_EXECUTE_r(PerlIO_printf(Perl_debug_log,
-               "Non-utf string cannot match utf check string\n"));
+               "Non-utf8 string cannot match utf8 check string\n"));
        goto fail;
     }
     if (prog->reganch & ROPT_ANCH) {   /* Match at beg-of-str or after \n */
@@ -490,6 +427,7 @@ Perl_re_intuit_start(pTHX_ regexp *prog, SV *sv, char *strpos,
            I32 slen;
 
            s = HOP3c(strpos, prog->check_offset_min, strend);
+           
            if (SvTAIL(check)) {
                slen = SvCUR(check);    /* >= 1 */
 
@@ -519,8 +457,8 @@ Perl_re_intuit_start(pTHX_ regexp *prog, SV *sv, char *strpos,
        /* 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->minlen - start_shift -
-           CHR_SVLEN(check) + (SvTAIL(check) != 0);
+       end_shift = prog->check_end_shift;
+       
        if (!ml_anch) {
            const I32 end = prog->check_offset_max + CHR_SVLEN(check)
                                         - (SvTAIL(check) != 0);
@@ -533,20 +471,37 @@ Perl_re_intuit_start(pTHX_ regexp *prog, SV *sv, char *strpos,
     else {                             /* Can match at random position */
        ml_anch = 0;
        s = strpos;
-       start_shift = prog->check_offset_min; /* okay to underestimate on CC */
-       /* Should be nonnegative! */
-       end_shift = prog->minlen - start_shift -
-           CHR_SVLEN(check) + (SvTAIL(check) != 0);
+       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 DEBUGGING       /* 7/99: reports of failure (with the older version) */
     if (end_shift < 0)
-       Perl_croak(aTHX_ "panic: end_shift");
+       Perl_croak(aTHX_ "panic: end_shift: %"IVdf" pattern:\n%s\n ",
+                  (IV)end_shift, prog->precomp);
 #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;
+        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 (flags & REXEC_SCREAM) {
        I32 p = -1;                     /* Internal iterator of scream. */
        I32 * const pp = data ? data->scream_pos : &p;
@@ -556,7 +511,7 @@ Perl_re_intuit_start(pTHX_ regexp *prog, SV *sv, char *strpos,
                 && (BmPREVIOUS(check) == SvCUR(check) - 1)
                 && SvTAIL(check) ))
            s = screaminstr(sv, check,
-                           start_shift + (s - strbeg), end_shift, pp, 0);
+                           srch_start_shift + (s - strbeg), srch_end_shift, pp, 0);
        else
            goto fail_finish;
        /* we may be pointing at the wrong string */
@@ -565,35 +520,58 @@ Perl_re_intuit_start(pTHX_ regexp *prog, SV *sv, char *strpos,
        if (data)
            *data->scream_olds = s;
     }
-    else if (prog->reganch & ROPT_CANY_SEEN)
-       s = fbm_instr((U8*)(s + start_shift),
-                     (U8*)(strend - end_shift),
-                     check, multiline ? FBMrf_MULTILINE : 0);
-    else
-       s = fbm_instr(HOP3(s, start_shift, strend),
-                     HOP3(strend, -end_shift, strbeg),
+    else {
+        U8* start_point;
+        U8* end_point;
+        if (prog->reganch & ROPT_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(PerlIO_printf(Perl_debug_log, "%s %s substr \"%s%.*s%s\"%s%s",
+    DEBUG_EXECUTE_r({
+        RE_PV_QUOTED_DECL(quoted, do_utf8, 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 == (do_utf8 ? prog->anchored_utf8 : prog->anchored_substr) ? "anchored" : "floating"),
-                         PL_colors[0],
-                         (int)(SvCUR(check) - (SvTAIL(check)!=0)),
-                         SvPVX_const(check),
-                         PL_colors[1], (SvTAIL(check) ? "$" : ""),
-                         (s ? " at offset " : "...\n") ) );
+           (check == (do_utf8 ? prog->anchored_utf8 : prog->anchored_substr) 
+               ? "anchored" : "floating"),
+           quoted,
+           RE_SV_TAIL(check),
+           (s ? " at offset " : "...\n") ); 
+    });
 
     if (!s)
        goto fail_finish;
-
-    check_at = s;
-
     /* 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
@@ -602,7 +580,9 @@ Perl_re_intuit_start(pTHX_ regexp *prog, SV *sv, char *strpos,
        Probably it is right to do no SCREAM here...
      */
 
-    if (do_utf8 ? (prog->float_utf8 && prog->anchored_utf8) : (prog->float_substr && prog->anchored_substr)) {
+    if (do_utf8 ? (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)
@@ -612,15 +592,15 @@ Perl_re_intuit_start(pTHX_ regexp *prog, SV *sv, char *strpos,
            {
                char * const last = HOP3c(s, -start_shift, strbeg);
                char *last1, *last2;
-               char *s1 = s;
+               char * const saved_s = s;
                SV* must;
 
                t = s - prog->check_offset_max;
                if (s - strpos > prog->check_offset_max  /* signed-corrected t > strpos */
                    && (!do_utf8
-                       || ((t = reghopmaybe3_c(s, -(prog->check_offset_max), strpos))
+                       || ((t = (char*)reghopmaybe3((U8*)s, -(prog->check_offset_max), (U8*)strpos))
                            && t > strpos)))
-                   /* EMPTY */;
+                   NOOP;
                else
                    t = strpos;
                t = HOP3c(t, prog->anchored_offset, strend);
@@ -629,12 +609,17 @@ Perl_re_intuit_start(pTHX_ regexp *prog, SV *sv, char *strpos,
                last2 = last1 = HOP3c(strend, -prog->minlen, strbeg);
                if (last < last1)
                    last1 = last;
- /* XXXX It is not documented what units *_offsets are in.  Assume bytes.  */
+                /* 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 = do_utf8 ? prog->anchored_utf8 : prog->anchored_substr;
                if (must == &PL_sv_undef) {
                    s = (char*)NULL;
-                   DEBUG_EXECUTE_r(must = prog->anchored_utf8);        /* for debug */
+                   DEBUG_r(must = prog->anchored_utf8);        /* for debug */
                }
                else
                    s = fbm_instr(
@@ -644,14 +629,15 @@ Perl_re_intuit_start(pTHX_ regexp *prog, SV *sv, char *strpos,
                        must,
                        multiline ? FBMrf_MULTILINE : 0
                    );
-               DEBUG_EXECUTE_r(PerlIO_printf(Perl_debug_log,
-                       "%s anchored substr \"%s%.*s%s\"%s",
+                DEBUG_EXECUTE_r({
+                    RE_PV_QUOTED_DECL(quoted, do_utf8, 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"),
-                       PL_colors[0],
-                         (int)(SvCUR(must)
-                         - (SvTAIL(must)!=0)),
-                         SvPVX_const(must),
-                         PL_colors[1], (SvTAIL(must) ? "$" : "")));
+                        quoted, RE_SV_TAIL(must));
+                });                
+               
+                           
                if (!s) {
                    if (last1 >= last2) {
                        DEBUG_EXECUTE_r(PerlIO_printf(Perl_debug_log,
@@ -660,7 +646,7 @@ Perl_re_intuit_start(pTHX_ regexp *prog, SV *sv, char *strpos,
                    }
                    DEBUG_EXECUTE_r(PerlIO_printf(Perl_debug_log,
                        ", trying floating at offset %ld...\n",
-                       (long)(HOP3c(s1, 1, strend) - i_strpos)));
+                       (long)(HOP3c(saved_s, 1, strend) - i_strpos)));
                    other_last = HOP3c(last1, prog->anchored_offset+1, strend);
                    s = HOP3c(last, 1, strend);
                    goto restart;
@@ -670,7 +656,7 @@ Perl_re_intuit_start(pTHX_ regexp *prog, SV *sv, char *strpos,
                          (long)(s - i_strpos)));
                    t = HOP3c(s, -prog->anchored_offset, strbeg);
                    other_last = HOP3c(s, 1, strend);
-                   s = s1;
+                   s = saved_s;
                    if (t == strpos)
                        goto try_at_start;
                    goto try_at_offset;
@@ -679,7 +665,7 @@ Perl_re_intuit_start(pTHX_ regexp *prog, SV *sv, char *strpos,
        }
        else {          /* Take into account the floating substring. */
            char *last, *last1;
-           char *s1 = s;
+           char * const saved_s = s;
            SV* must;
 
            t = HOP3c(s, -start_shift, strbeg);
@@ -697,19 +683,20 @@ Perl_re_intuit_start(pTHX_ regexp *prog, SV *sv, char *strpos,
               and end-of-str is not later than strend we are OK. */
            if (must == &PL_sv_undef) {
                s = (char*)NULL;
-               DEBUG_EXECUTE_r(must = prog->float_utf8);       /* for debug message */
+               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(PerlIO_printf(Perl_debug_log, "%s floating substr \"%s%.*s%s\"%s",
+           DEBUG_EXECUTE_r({
+               RE_PV_QUOTED_DECL(quoted, do_utf8, 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"),
-                   PL_colors[0],
-                     (int)(SvCUR(must) - (SvTAIL(must)!=0)),
-                     SvPVX_const(must),
-                     PL_colors[1], (SvTAIL(must) ? "$" : "")));
+                   quoted, RE_SV_TAIL(must));
+            });
            if (!s) {
                if (last1 == last) {
                    DEBUG_EXECUTE_r(PerlIO_printf(Perl_debug_log,
@@ -718,7 +705,7 @@ Perl_re_intuit_start(pTHX_ regexp *prog, SV *sv, char *strpos,
                }
                DEBUG_EXECUTE_r(PerlIO_printf(Perl_debug_log,
                    ", trying anchored starting at offset %ld...\n",
-                   (long)(s1 + 1 - i_strpos)));
+                   (long)(saved_s + 1 - i_strpos)));
                other_last = last;
                s = HOP3c(t, 1, strend);
                goto restart;
@@ -727,7 +714,7 @@ Perl_re_intuit_start(pTHX_ regexp *prog, SV *sv, char *strpos,
                DEBUG_EXECUTE_r(PerlIO_printf(Perl_debug_log, " at offset %ld...\n",
                      (long)(s - i_strpos)));
                other_last = s; /* Fix this later. --Hugo */
-               s = s1;
+               s = saved_s;
                if (t == strpos)
                    goto try_at_start;
                goto try_at_offset;
@@ -735,11 +722,26 @@ Perl_re_intuit_start(pTHX_ regexp *prog, SV *sv, char *strpos,
        }
     }
 
-    t = s - prog->check_offset_max;
+    
+    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 */
         && (!do_utf8
-           || ((t = reghopmaybe3_c(s, -prog->check_offset_max, strpos))
-                && t > strpos))) {
+           || ((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:
@@ -848,7 +850,9 @@ Perl_re_intuit_start(pTHX_ regexp *prog, SV *sv, char *strpos,
 
     /* Last resort... */
     /* XXXX BmUSEFUL already changed, maybe multiple change is meaningful... */
-    if (prog->regstclass) {
+    /* trie stclasses are too expensive to use here, we are better off to
+       leave it to regmatch itself */
+    if (prog->regstclass && PL_regkind[OP(prog->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;
@@ -858,19 +862,22 @@ Perl_re_intuit_start(pTHX_ regexp *prog, SV *sv, char *strpos,
        /* If regstclass takes bytelength more than 1: If charlength==1, OK.
           This leaves EXACTF only, which is dealt with in find_byclass().  */
         const U8* const str = (U8*)STRING(prog->regstclass);
-        const int cl_l = (PL_regkind[(U8)OP(prog->regstclass)] == EXACT
+        const int cl_l = (PL_regkind[OP(prog->regstclass)] == EXACT
                    ? CHR_DIST(str+STR_LEN(prog->regstclass), str)
                    : 1);
-       const char * const endpos = (prog->anchored_substr || prog->anchored_utf8 || ml_anch)
-               ? HOP3c(s, (prog->minlen ? cl_l : 0), strend)
-               : (prog->float_substr || prog->float_utf8
-                  ? HOP3c(HOP3c(check_at, -start_shift, strbeg),
-                          cl_l, strend)
-                  : strend);
-
+       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;
+                   
+        DEBUG_EXECUTE_r(PerlIO_printf(Perl_debug_log, "start_shift: %"IVdf" check_at: %d s: %d endpos: %d\n",
+                                     (IV)start_shift, check_at - strbeg, s - strbeg, endpos - strbeg));
+       
        t = s;
-       cache_re(prog);
-        s = find_byclass(prog, prog->regstclass, s, endpos, 1);
+        s = find_byclass(prog, prog->regstclass, s, endpos, NULL);
        if (!s) {
 #ifdef DEBUGGING
            const char *what = NULL;
@@ -961,9 +968,157 @@ Perl_re_intuit_start(pTHX_ regexp *prog, SV *sv, char *strpos,
     return NULL;
 }
 
+
+
+#define REXEC_TRIE_READ_CHAR(trie_type, trie, uc, uscan, len, uvc, charid,  \
+foldlen, foldbuf, uniflags) STMT_START {                                    \
+    switch (trie_type) {                                                    \
+    case trie_utf8_fold:                                                    \
+       if ( foldlen>0 ) {                                                  \
+           uvc = utf8n_to_uvuni( uscan, UTF8_MAXLEN, &len, uniflags );     \
+           foldlen -= len;                                                 \
+           uscan += len;                                                   \
+           len=0;                                                          \
+       } else {                                                            \
+           uvc = utf8n_to_uvuni( (U8*)uc, UTF8_MAXLEN, &len, uniflags );   \
+           uvc = to_uni_fold( uvc, foldbuf, &foldlen );                    \
+           foldlen -= UNISKIP( uvc );                                      \
+           uscan = foldbuf + UNISKIP( uvc );                               \
+       }                                                                   \
+       break;                                                              \
+    case trie_utf8:                                                         \
+       uvc = utf8n_to_uvuni( (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 (trie->widecharmap) {                                            \
+           SV** const svpp = hv_fetch(trie->widecharmap,                   \
+                       (char*)&uvc, sizeof(UV), 0);                        \
+           if (svpp)                                                       \
+               charid = (U16)SvIV(*svpp);                                  \
+       }                                                                   \
+    }                                                                       \
+} STMT_END
+
+#define REXEC_FBC_EXACTISH_CHECK(CoNd)                  \
+    if ( (CoNd)                                        \
+        && (ln == len ||                              \
+            ibcmp_utf8(s, NULL, 0,  do_utf8,          \
+                       m, NULL, ln, (bool)UTF))       \
+        && (!reginfo || regtry(reginfo, s)) )         \
+       goto got_it;                                   \
+    else {                                             \
+        U8 foldbuf[UTF8_MAXBYTES_CASE+1];             \
+        uvchr_to_utf8(tmpbuf, c);                     \
+        f = to_utf8_fold(tmpbuf, foldbuf, &foldlen);  \
+        if ( f != c                                   \
+             && (f == c1 || f == c2)                  \
+             && (ln == foldlen ||                     \
+                 !ibcmp_utf8((char *) foldbuf,        \
+                             NULL, foldlen, do_utf8,  \
+                             m,                       \
+                             NULL, ln, (bool)UTF))    \
+             && (!reginfo || regtry(reginfo, s)) )    \
+             goto got_it;                             \
+    }                                                  \
+    s += len
+
+#define REXEC_FBC_EXACTISH_SCAN(CoNd)                     \
+STMT_START {                                              \
+    while (s <= e) {                                      \
+       if ( (CoNd)                                       \
+            && (ln == 1 || !(OP(c) == EXACTF             \
+                             ? ibcmp(s, m, ln)           \
+                             : ibcmp_locale(s, m, ln)))  \
+            && (!reginfo || regtry(reginfo, s)) )        \
+           goto got_it;                                  \
+       s++;                                              \
+    }                                                     \
+} STMT_END
+
+#define REXEC_FBC_UTF8_SCAN(CoDe)                     \
+STMT_START {                                          \
+    while (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_PRELOAD(UtFpReLoAd,CoNdUtF8,CoNd)      \
+    if (do_utf8) {                                             \
+       UtFpReLoAd;                                            \
+       REXEC_FBC_UTF8_CLASS_SCAN(CoNdUtF8);                   \
+    }                                                          \
+    else {                                                     \
+       REXEC_FBC_CLASS_SCAN(CoNd);                            \
+    }                                                          \
+    break
+
+#define REXEC_FBC_CSCAN_TAINT(CoNdUtF8,CoNd)                   \
+    PL_reg_flags |= RF_tainted;                                \
+    if (do_utf8) {                                             \
+       REXEC_FBC_UTF8_CLASS_SCAN(CoNdUtF8);                   \
+    }                                                          \
+    else {                                                     \
+       REXEC_FBC_CLASS_SCAN(CoNd);                            \
+    }                                                          \
+    break
+
+#define DUMP_EXEC_POS(li,s,doutf8) \
+    dump_exec_pos(li,s,(PL_regeol),(PL_bostr),(PL_reg_starttry),doutf8)
+
 /* 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, regnode *c, char *s, const char *strend, I32 norun)
+S_find_byclass(pTHX_ regexp * prog, const regnode *c, char *s, 
+    const char *strend, const regmatch_info *reginfo)
 {
        dVAR;
        const I32 doevery = (prog->reganch & ROPT_SKIP) == 0;
@@ -981,31 +1136,21 @@ S_find_byclass(pTHX_ regexp * prog, regnode *c, char *s, const char *strend, I32
        switch (OP(c)) {
        case ANYOF:
            if (do_utf8) {
-                while (s + (uskip = UTF8SKIP(s)) <= strend) {
-                     if ((ANYOF_FLAGS(c) & ANYOF_UNICODE) ||
+                REXEC_FBC_UTF8_CLASS_SCAN((ANYOF_FLAGS(c) & ANYOF_UNICODE) ||
                          !UTF8_IS_INVARIANT((U8)s[0]) ?
-                         reginclass(c, (U8*)s, 0, do_utf8) :
-                         REGINCLASS(c, (U8*)s)) {
-                          if (tmp && (norun || regtry(prog, s)))
-                               goto got_it;
-                          else
-                               tmp = doevery;
-                     }
-                     else 
-                          tmp = 1;
-                     s += uskip;
-                }
+                         reginclass(prog, c, (U8*)s, 0, do_utf8) :
+                         REGINCLASS(prog, c, (U8*)s));
            }
            else {
                 while (s < strend) {
                      STRLEN skip = 1;
 
-                     if (REGINCLASS(c, (U8*)s) ||
+                     if (REGINCLASS(prog, c, (U8*)s) ||
                          (ANYOF_FOLD_SHARP_S(c, s, strend) &&
                           /* The assignment of 2 is intentional:
                            * for the folded sharp s, the skip is 2. */
                           (skip = SHARP_S_SKIP))) {
-                          if (tmp && (norun || regtry(prog, s)))
+                          if (tmp && (!reginfo || regtry(reginfo, s)))
                                goto got_it;
                           else
                                tmp = doevery;
@@ -1017,13 +1162,12 @@ S_find_byclass(pTHX_ regexp * prog, regnode *c, char *s, const char *strend, I32
            }
            break;
        case CANY:
-           while (s < strend) {
-               if (tmp && (norun || regtry(prog, s)))
+           REXEC_FBC_SCAN(
+               if (tmp && (!reginfo || regtry(reginfo, s)))
                    goto got_it;
                else
                    tmp = doevery;
-               s++;
-           }
+           );
            break;
        case EXACTF:
            m   = STRING(c);
@@ -1034,7 +1178,7 @@ S_find_byclass(pTHX_ regexp * prog, regnode *c, char *s, const char *strend, I32
                U8 *sm = (U8 *) m;
                U8 tmpbuf1[UTF8_MAXBYTES_CASE+1];
                U8 tmpbuf2[UTF8_MAXBYTES_CASE+1];
-               const U32 uniflags = ckWARN(WARN_UTF8) ? 0 : UTF8_ALLOW_ANY;
+               const U32 uniflags = UTF8_ALLOW_DEFAULT;
 
                to_utf8_lower((U8*)m, tmpbuf1, &ulen1);
                to_utf8_upper((U8*)m, tmpbuf2, &ulen2);
@@ -1063,7 +1207,7 @@ S_find_byclass(pTHX_ regexp * prog, regnode *c, char *s, const char *strend, I32
          do_exactf:
            e = HOP3c(strend, -((I32)lnc), s);
 
-           if (norun && e < s)
+           if (!reginfo && e < s)
                e = s;                  /* Due to minlen logic of intuit() */
 
            /* The idea in the EXACTF* cases is to first find the
@@ -1081,34 +1225,14 @@ S_find_byclass(pTHX_ regexp * prog, regnode *c, char *s, const char *strend, I32
                UV c, f;
                U8 tmpbuf [UTF8_MAXBYTES+1];
                STRLEN len, foldlen;
-               const U32 uniflags = ckWARN(WARN_UTF8) ? 0 : UTF8_ALLOW_ANY;
+               const U32 uniflags = UTF8_ALLOW_DEFAULT;
                if (c1 == c2) {
                    /* Upper and lower of 1st char are equal -
                     * probably not a "letter". */
                    while (s <= e) {
                        c = utf8n_to_uvchr((U8*)s, UTF8_MAXBYTES, &len,
                                           uniflags);
-                       if ( c == c1
-                            && (ln == len ||
-                                ibcmp_utf8(s, (char **)0, 0,  do_utf8,
-                                           m, (char **)0, ln, (bool)UTF))
-                            && (norun || regtry(prog, s)) )
-                           goto got_it;
-                       else {
-                            U8 foldbuf[UTF8_MAXBYTES_CASE+1];
-                            uvchr_to_utf8(tmpbuf, c);
-                            f = to_utf8_fold(tmpbuf, foldbuf, &foldlen);
-                            if ( f != c
-                                 && (f == c1 || f == c2)
-                                 && (ln == foldlen ||
-                                     !ibcmp_utf8((char *) foldbuf,
-                                                 (char **)0, foldlen, do_utf8,
-                                                 m,
-                                                 (char **)0, ln, (bool)UTF))
-                                 && (norun || regtry(prog, s)) )
-                                 goto got_it;
-                       }
-                       s += len;
+                       REXEC_FBC_EXACTISH_CHECK(c == c1);
                    }
                }
                else {
@@ -1127,51 +1251,15 @@ S_find_byclass(pTHX_ regexp * prog, regnode *c, char *s, const char *strend, I32
                            c == (UV)UNICODE_GREEK_SMALL_LETTER_FINAL_SIGMA)
                            c = (UV)UNICODE_GREEK_SMALL_LETTER_SIGMA;
 
-                       if ( (c == c1 || c == c2)
-                            && (ln == len ||
-                                ibcmp_utf8(s, (char **)0, 0,  do_utf8,
-                                           m, (char **)0, ln, (bool)UTF))
-                            && (norun || regtry(prog, s)) )
-                           goto got_it;
-                       else {
-                            U8 foldbuf[UTF8_MAXBYTES_CASE+1];
-                            uvchr_to_utf8(tmpbuf, c);
-                            f = to_utf8_fold(tmpbuf, foldbuf, &foldlen);
-                            if ( f != c
-                                 && (f == c1 || f == c2)
-                                 && (ln == foldlen ||
-                                     !ibcmp_utf8((char *) foldbuf,
-                                                 (char **)0, foldlen, do_utf8,
-                                                 m,
-                                                 (char **)0, ln, (bool)UTF))
-                                 && (norun || regtry(prog, s)) )
-                                 goto got_it;
-                       }
-                       s += len;
+                       REXEC_FBC_EXACTISH_CHECK(c == c1 || c == c2);
                    }
                }
            }
            else {
                if (c1 == c2)
-                   while (s <= e) {
-                       if ( *(U8*)s == c1
-                            && (ln == 1 || !(OP(c) == EXACTF
-                                             ? ibcmp(s, m, ln)
-                                             : ibcmp_locale(s, m, ln)))
-                            && (norun || regtry(prog, s)) )
-                           goto got_it;
-                       s++;
-                   }
+                   REXEC_FBC_EXACTISH_SCAN(*(U8*)s == c1);
                else
-                   while (s <= e) {
-                       if ( (*(U8*)s == c1 || *(U8*)s == c2)
-                            && (ln == 1 || !(OP(c) == EXACTF
-                                             ? ibcmp(s, m, ln)
-                                             : ibcmp_locale(s, m, ln)))
-                            && (norun || regtry(prog, s)) )
-                           goto got_it;
-                       s++;
-                   }
+                   REXEC_FBC_EXACTISH_SCAN(*(U8*)s == c1 || *(U8*)s == c2);
            }
            break;
        case BOUNDL:
@@ -1183,37 +1271,33 @@ S_find_byclass(pTHX_ regexp * prog, regnode *c, char *s, const char *strend, I32
                    tmp = '\n';
                else {
                    U8 * const r = reghop3((U8*)s, -1, (U8*)PL_bostr);
-                   tmp = utf8n_to_uvchr(r, UTF8SKIP(r), 0, 0);
+                   tmp = utf8n_to_uvchr(r, UTF8SKIP(r), 0, UTF8_ALLOW_DEFAULT);
                }
                tmp = ((OP(c) == BOUND ?
                        isALNUM_uni(tmp) : isALNUM_LC_uvchr(UNI_TO_NATIVE(tmp))) != 0);
                LOAD_UTF8_CHARCLASS_ALNUM();
-               while (s + (uskip = UTF8SKIP(s)) <= strend) {
+               REXEC_FBC_UTF8_SCAN(
                    if (tmp == !(OP(c) == BOUND ?
-                                swash_fetch(PL_utf8_alnum, (U8*)s, do_utf8) :
+                                (bool)swash_fetch(PL_utf8_alnum, (U8*)s, do_utf8) :
                                 isALNUM_LC_utf8((U8*)s)))
                    {
                        tmp = !tmp;
-                       if ((norun || regtry(prog, s)))
-                           goto got_it;
-                   }
-                   s += uskip;
+                       REXEC_FBC_TRYIT;
                }
+               );
            }
            else {
                tmp = (s != PL_bostr) ? UCHARAT(s - 1) : '\n';
                tmp = ((OP(c) == BOUND ? isALNUM(tmp) : isALNUM_LC(tmp)) != 0);
-               while (s < strend) {
+               REXEC_FBC_SCAN(
                    if (tmp ==
                        !(OP(c) == BOUND ? isALNUM(*s) : isALNUM_LC(*s))) {
                        tmp = !tmp;
-                       if ((norun || regtry(prog, s)))
-                           goto got_it;
-                   }
-                   s++;
+                       REXEC_FBC_TRYIT;
                }
+               );
            }
-           if ((!prog->minlen && tmp) && (norun || regtry(prog, s)))
+           if ((!prog->minlen && tmp) && (!reginfo || regtry(reginfo, s)))
                goto got_it;
            break;
        case NBOUNDL:
@@ -1225,383 +1309,307 @@ S_find_byclass(pTHX_ regexp * prog, regnode *c, char *s, const char *strend, I32
                    tmp = '\n';
                else {
                    U8 * const r = reghop3((U8*)s, -1, (U8*)PL_bostr);
-                   tmp = utf8n_to_uvchr(r, UTF8SKIP(r), 0, 0);
+                   tmp = utf8n_to_uvchr(r, UTF8SKIP(r), 0, UTF8_ALLOW_DEFAULT);
                }
                tmp = ((OP(c) == NBOUND ?
                        isALNUM_uni(tmp) : isALNUM_LC_uvchr(UNI_TO_NATIVE(tmp))) != 0);
                LOAD_UTF8_CHARCLASS_ALNUM();
-               while (s + (uskip = UTF8SKIP(s)) <= strend) {
+               REXEC_FBC_UTF8_SCAN(
                    if (tmp == !(OP(c) == NBOUND ?
-                                swash_fetch(PL_utf8_alnum, (U8*)s, do_utf8) :
+                                (bool)swash_fetch(PL_utf8_alnum, (U8*)s, do_utf8) :
                                 isALNUM_LC_utf8((U8*)s)))
                        tmp = !tmp;
-                   else if ((norun || regtry(prog, s)))
-                       goto got_it;
-                   s += uskip;
-               }
+                   else REXEC_FBC_TRYIT;
+               );
            }
            else {
                tmp = (s != PL_bostr) ? UCHARAT(s - 1) : '\n';
                tmp = ((OP(c) == NBOUND ?
                        isALNUM(tmp) : isALNUM_LC(tmp)) != 0);
-               while (s < strend) {
+               REXEC_FBC_SCAN(
                    if (tmp ==
                        !(OP(c) == NBOUND ? isALNUM(*s) : isALNUM_LC(*s)))
                        tmp = !tmp;
-                   else if ((norun || regtry(prog, s)))
-                       goto got_it;
-                   s++;
-               }
+                   else REXEC_FBC_TRYIT;
+               );
            }
-           if ((!prog->minlen && !tmp) && (norun || regtry(prog, s)))
+           if ((!prog->minlen && !tmp) && (!reginfo || regtry(reginfo, s)))
                goto got_it;
            break;
        case ALNUM:
-           if (do_utf8) {
-               LOAD_UTF8_CHARCLASS_ALNUM();
-               while (s + (uskip = UTF8SKIP(s)) <= strend) {
-                   if (swash_fetch(PL_utf8_alnum, (U8*)s, do_utf8)) {
-                       if (tmp && (norun || regtry(prog, s)))
-                           goto got_it;
-                       else
-                           tmp = doevery;
-                   }
-                   else
-                       tmp = 1;
-                   s += uskip;
-               }
-           }
-           else {
-               while (s < strend) {
-                   if (isALNUM(*s)) {
-                       if (tmp && (norun || regtry(prog, s)))
-                           goto got_it;
-                       else
-                           tmp = doevery;
-                   }
-                   else
-                       tmp = 1;
-                   s++;
-               }
-           }
-           break;
+           REXEC_FBC_CSCAN_PRELOAD(
+               LOAD_UTF8_CHARCLASS_ALNUM(),
+               swash_fetch(PL_utf8_alnum, (U8*)s, do_utf8),
+               isALNUM(*s)
+           );
        case ALNUML:
-           PL_reg_flags |= RF_tainted;
-           if (do_utf8) {
-               while (s + (uskip = UTF8SKIP(s)) <= strend) {
-                   if (isALNUM_LC_utf8((U8*)s)) {
-                       if (tmp && (norun || regtry(prog, s)))
-                           goto got_it;
-                       else
-                           tmp = doevery;
-                   }
-                   else
-                       tmp = 1;
-                   s += uskip;
-               }
-           }
-           else {
-               while (s < strend) {
-                   if (isALNUM_LC(*s)) {
-                       if (tmp && (norun || regtry(prog, s)))
-                           goto got_it;
-                       else
-                           tmp = doevery;
-                   }
-                   else
-                       tmp = 1;
-                   s++;
-               }
-           }
-           break;
+           REXEC_FBC_CSCAN_TAINT(
+               isALNUM_LC_utf8((U8*)s),
+               isALNUM_LC(*s)
+           );
        case NALNUM:
-           if (do_utf8) {
-               LOAD_UTF8_CHARCLASS_ALNUM();
-               while (s + (uskip = UTF8SKIP(s)) <= strend) {
-                   if (!swash_fetch(PL_utf8_alnum, (U8*)s, do_utf8)) {
-                       if (tmp && (norun || regtry(prog, s)))
-                           goto got_it;
-                       else
-                           tmp = doevery;
-                   }
-                   else
-                       tmp = 1;
-                   s += uskip;
-               }
-           }
-           else {
-               while (s < strend) {
-                   if (!isALNUM(*s)) {
-                       if (tmp && (norun || regtry(prog, s)))
-                           goto got_it;
-                       else
-                           tmp = doevery;
-                   }
-                   else
-                       tmp = 1;
-                   s++;
-               }
-           }
-           break;
+           REXEC_FBC_CSCAN_PRELOAD(
+               LOAD_UTF8_CHARCLASS_ALNUM(),
+               !swash_fetch(PL_utf8_alnum, (U8*)s, do_utf8),
+               !isALNUM(*s)
+           );
        case NALNUML:
-           PL_reg_flags |= RF_tainted;
-           if (do_utf8) {
-               while (s + (uskip = UTF8SKIP(s)) <= strend) {
-                   if (!isALNUM_LC_utf8((U8*)s)) {
-                       if (tmp && (norun || regtry(prog, s)))
-                           goto got_it;
-                       else
-                           tmp = doevery;
-                   }
-                   else
-                       tmp = 1;
-                   s += uskip;
-               }
-           }
-           else {
-               while (s < strend) {
-                   if (!isALNUM_LC(*s)) {
-                       if (tmp && (norun || regtry(prog, s)))
-                           goto got_it;
-                       else
-                           tmp = doevery;
-                   }
-                   else
-                       tmp = 1;
-                   s++;
-               }
-           }
-           break;
+           REXEC_FBC_CSCAN_TAINT(
+               !isALNUM_LC_utf8((U8*)s),
+               !isALNUM_LC(*s)
+           );
        case SPACE:
-           if (do_utf8) {
-               LOAD_UTF8_CHARCLASS_SPACE();
-               while (s + (uskip = UTF8SKIP(s)) <= strend) {
-                   if (*s == ' ' || swash_fetch(PL_utf8_space,(U8*)s, do_utf8)) {
-                       if (tmp && (norun || regtry(prog, s)))
-                           goto got_it;
-                       else
-                           tmp = doevery;
-                   }
-                   else
-                       tmp = 1;
-                   s += uskip;
-               }
-           }
-           else {
-               while (s < strend) {
-                   if (isSPACE(*s)) {
-                       if (tmp && (norun || regtry(prog, s)))
-                           goto got_it;
-                       else
-                           tmp = doevery;
-                   }
-                   else
-                       tmp = 1;
-                   s++;
-               }
-           }
-           break;
+           REXEC_FBC_CSCAN_PRELOAD(
+               LOAD_UTF8_CHARCLASS_SPACE(),
+               *s == ' ' || swash_fetch(PL_utf8_space,(U8*)s, do_utf8),
+               isSPACE(*s)
+           );
        case SPACEL:
-           PL_reg_flags |= RF_tainted;
-           if (do_utf8) {
-               while (s + (uskip = UTF8SKIP(s)) <= strend) {
-                   if (*s == ' ' || isSPACE_LC_utf8((U8*)s)) {
-                       if (tmp && (norun || regtry(prog, s)))
-                           goto got_it;
-                       else
-                           tmp = doevery;
-                   }
-                   else
-                       tmp = 1;
-                   s += uskip;
-               }
-           }
-           else {
-               while (s < strend) {
-                   if (isSPACE_LC(*s)) {
-                       if (tmp && (norun || regtry(prog, s)))
-                           goto got_it;
-                       else
-                           tmp = doevery;
-                   }
-                   else
-                       tmp = 1;
-                   s++;
-               }
-           }
-           break;
+           REXEC_FBC_CSCAN_TAINT(
+               *s == ' ' || isSPACE_LC_utf8((U8*)s),
+               isSPACE_LC(*s)
+           );
        case NSPACE:
-           if (do_utf8) {
-               LOAD_UTF8_CHARCLASS_SPACE();
-               while (s + (uskip = UTF8SKIP(s)) <= strend) {
-                   if (!(*s == ' ' || swash_fetch(PL_utf8_space,(U8*)s, do_utf8))) {
-                       if (tmp && (norun || regtry(prog, s)))
-                           goto got_it;
-                       else
-                           tmp = doevery;
-                   }
-                   else
-                       tmp = 1;
-                   s += uskip;
-               }
-           }
-           else {
-               while (s < strend) {
-                   if (!isSPACE(*s)) {
-                       if (tmp && (norun || regtry(prog, s)))
-                           goto got_it;
-                       else
-                           tmp = doevery;
-                   }
-                   else
-                       tmp = 1;
-                   s++;
-               }
-           }
-           break;
+           REXEC_FBC_CSCAN_PRELOAD(
+               LOAD_UTF8_CHARCLASS_SPACE(),
+               !(*s == ' ' || swash_fetch(PL_utf8_space,(U8*)s, do_utf8)),
+               !isSPACE(*s)
+           );
        case NSPACEL:
-           PL_reg_flags |= RF_tainted;
-           if (do_utf8) {
-               while (s + (uskip = UTF8SKIP(s)) <= strend) {
-                   if (!(*s == ' ' || isSPACE_LC_utf8((U8*)s))) {
-                       if (tmp && (norun || regtry(prog, s)))
-                           goto got_it;
-                       else
-                           tmp = doevery;
-                   }
-                   else
-                       tmp = 1;
-                   s += uskip;
-               }
-           }
-           else {
-               while (s < strend) {
-                   if (!isSPACE_LC(*s)) {
-                       if (tmp && (norun || regtry(prog, s)))
-                           goto got_it;
-                       else
-                           tmp = doevery;
-                   }
-                   else
-                       tmp = 1;
-                   s++;
-               }
-           }
-           break;
+           REXEC_FBC_CSCAN_TAINT(
+               !(*s == ' ' || isSPACE_LC_utf8((U8*)s)),
+               !isSPACE_LC(*s)
+           );
        case DIGIT:
-           if (do_utf8) {
-               LOAD_UTF8_CHARCLASS_DIGIT();
-               while (s + (uskip = UTF8SKIP(s)) <= strend) {
-                   if (swash_fetch(PL_utf8_digit,(U8*)s, do_utf8)) {
-                       if (tmp && (norun || regtry(prog, s)))
-                           goto got_it;
-                       else
-                           tmp = doevery;
-                   }
-                   else
-                       tmp = 1;
-                   s += uskip;
-               }
-           }
-           else {
-               while (s < strend) {
-                   if (isDIGIT(*s)) {
-                       if (tmp && (norun || regtry(prog, s)))
-                           goto got_it;
-                       else
-                           tmp = doevery;
-                   }
-                   else
-                       tmp = 1;
-                   s++;
-               }
-           }
-           break;
+           REXEC_FBC_CSCAN_PRELOAD(
+               LOAD_UTF8_CHARCLASS_DIGIT(),
+               swash_fetch(PL_utf8_digit,(U8*)s, do_utf8),
+               isDIGIT(*s)
+           );
        case DIGITL:
-           PL_reg_flags |= RF_tainted;
-           if (do_utf8) {
-               while (s + (uskip = UTF8SKIP(s)) <= strend) {
-                   if (isDIGIT_LC_utf8((U8*)s)) {
-                       if (tmp && (norun || regtry(prog, s)))
-                           goto got_it;
-                       else
-                           tmp = doevery;
-                   }
-                   else
-                       tmp = 1;
-                   s += uskip;
-               }
-           }
-           else {
-               while (s < strend) {
-                   if (isDIGIT_LC(*s)) {
-                       if (tmp && (norun || regtry(prog, s)))
-                           goto got_it;
-                       else
-                           tmp = doevery;
-                   }
-                   else
-                       tmp = 1;
-                   s++;
-               }
-           }
-           break;
+           REXEC_FBC_CSCAN_TAINT(
+               isDIGIT_LC_utf8((U8*)s),
+               isDIGIT_LC(*s)
+           );
        case NDIGIT:
-           if (do_utf8) {
-               LOAD_UTF8_CHARCLASS_DIGIT();
-               while (s + (uskip = UTF8SKIP(s)) <= strend) {
-                   if (!swash_fetch(PL_utf8_digit,(U8*)s, do_utf8)) {
-                       if (tmp && (norun || regtry(prog, s)))
-                           goto got_it;
-                       else
-                           tmp = doevery;
-                   }
-                   else
-                       tmp = 1;
-                   s += uskip;
-               }
-           }
-           else {
-               while (s < strend) {
-                   if (!isDIGIT(*s)) {
-                       if (tmp && (norun || regtry(prog, s)))
-                           goto got_it;
-                       else
-                           tmp = doevery;
-                   }
-                   else
-                       tmp = 1;
-                   s++;
-               }
-           }
-           break;
+           REXEC_FBC_CSCAN_PRELOAD(
+               LOAD_UTF8_CHARCLASS_DIGIT(),
+               !swash_fetch(PL_utf8_digit,(U8*)s, do_utf8),
+               !isDIGIT(*s)
+           );
        case NDIGITL:
-           PL_reg_flags |= RF_tainted;
-           if (do_utf8) {
-               while (s + (uskip = UTF8SKIP(s)) <= strend) {
-                   if (!isDIGIT_LC_utf8((U8*)s)) {
-                       if (tmp && (norun || regtry(prog, s)))
-                           goto got_it;
-                       else
-                           tmp = doevery;
-                   }
-                   else
-                       tmp = 1;
-                   s += uskip;
-               }
-           }
-           else {
-               while (s < strend) {
-                   if (!isDIGIT_LC(*s)) {
-                       if (tmp && (norun || regtry(prog, s)))
-                           goto got_it;
-                       else
-                           tmp = doevery;
-                   }
-                   else
-                       tmp = 1;
-                   s++;
-               }
+           REXEC_FBC_CSCAN_TAINT(
+               !isDIGIT_LC_utf8((U8*)s),
+               !isDIGIT_LC(*s)
+           );
+       case AHOCORASICKC:
+       case AHOCORASICK: 
+           {
+               const enum { trie_plain, trie_utf8, trie_utf8_fold }
+                   trie_type = do_utf8 ?
+                         (c->flags == EXACT ? trie_utf8 : trie_utf8_fold)
+                       : trie_plain;
+                /* what trie are we using right now */
+               reg_ac_data *aho
+                   = (reg_ac_data*)prog->data->data[ ARG( c ) ];
+               reg_trie_data *trie=aho->trie;
+
+               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, do_utf8 );
+                                        PerlIO_printf( Perl_debug_log,
+                                            " Scanning for legal start char...\n");
+                                    }
+                                );            
+                                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->wordlen[word-1] ) % maxlen ];
+                            if (!leftmost || lpos < leftmost) {
+                                DEBUG_r(accepted_word=word);
+                                leftmost= lpos;
+                            }
+                            if (base==0) break;
+                            
+                        }
+                        points[pointpos++ % maxlen]= uc;
+                       REXEC_TRIE_READ_CHAR(trie_type, trie, uc, uscan, len,
+                           uvc, charid, foldlen, foldbuf, uniflags);
+                        DEBUG_TRIE_EXECUTE_r({
+                            dump_exec_pos( (char *)uc, c, strend, real_start, 
+                                s,   do_utf8 );
+                            PerlIO_printf(Perl_debug_log,
+                                " Charid:%3u CP:%4"UVxf" ",
+                                 charid, uvc);
+                        });
+
+                        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,   do_utf8 );
+                                PerlIO_printf( Perl_debug_log,
+                                    "%sState: %4"UVxf", word=%"UVxf,
+                                    failed ? " Fail transition to " : "",
+                                    (UV)state, (UV)word);
+                            });
+                            if ( base ) {
+                                U32 tmp;
+                                if (charid &&
+                                     (base + charid > trie->uniquecharcount )
+                                     && (base + charid - 1 - trie->uniquecharcount
+                                            < trie->lasttrans)
+                                     && trie->trans[base + charid - 1 -
+                                            trie->uniquecharcount].check == state
+                                     && (tmp=trie->trans[base + charid - 1 -
+                                        trie->uniquecharcount ].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->wordlen[aho->states[ state ].wordnum-1]) % 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 %d. Trying full pattern...\n",
+                                (UV)accepted_word, 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:
@@ -1634,23 +1642,15 @@ Perl_regexec_flags(pTHX_ register regexp *prog, char *stringarg, register char *
     I32 end_shift = 0;                 /* Same for the end. */         /* CC */
     I32 scream_pos = -1;               /* Internal iterator of scream. */
     char *scream_olds = NULL;
-    SV* oreplsv = GvSV(PL_replgv);
-    const bool do_utf8 = DO_UTF8(sv);
-    const I32 multiline = prog->reganch & PMf_MULTILINE;
-#ifdef DEBUGGING
-    SV * const dsv0 = PERL_DEBUG_PAD_ZERO(0);
-    SV * const dsv1 = PERL_DEBUG_PAD_ZERO(1);
-#endif
+    SV* const oreplsv = GvSV(PL_replgv);
+    const bool do_utf8 = (bool)DO_UTF8(sv);
+    I32 multiline;
+
+    regmatch_info reginfo;  /* create some info to pass to regtry etc */
 
     GET_RE_DEBUG_FLAGS_DECL;
 
     PERL_UNUSED_ARG(data);
-    RX_MATCH_UTF8_set(prog,do_utf8);
-
-    cache_re(prog);
-#ifdef DEBUGGING
-    PL_regnarrate = DEBUG_r_TEST;
-#endif
 
     /* Be paranoid... */
     if (prog == NULL || startpos == NULL) {
@@ -1658,13 +1658,24 @@ Perl_regexec_flags(pTHX_ register regexp *prog, char *stringarg, register char *
        return 0;
     }
 
+    multiline = prog->reganch & PMf_MULTILINE;
+    reginfo.prog = prog;
+
+    RX_MATCH_UTF8_set(prog, do_utf8);
+    DEBUG_EXECUTE_r( 
+        debug_start_match(prog, do_utf8, startpos, strend, 
+        "Matching");
+    );
+
     minlen = prog->minlen;
-    if (strend - startpos < 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(prog->program) != REG_MAGIC) {
        Perl_croak(aTHX_ "corrupted regexp program");
@@ -1678,40 +1689,37 @@ Perl_regexec_flags(pTHX_ register regexp *prog, char *stringarg, register char *
        PL_reg_flags |= RF_utf8;
 
     /* Mark beginning of line for ^ and lookbehind. */
-    PL_regbol = startpos;
+    reginfo.bol = startpos; /* XXX not used ??? */
     PL_bostr  = strbeg;
-    PL_reg_sv = sv;
+    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 */
-    PL_regtill = startpos+minend;
-
-    /* We start without call_cc context.  */
-    PL_reg_call_cc = 0;
+    reginfo.till = startpos+minend;
 
     /* If there is a "must appear" string, look for it. */
     s = startpos;
 
-    if (prog->reganch & ROPT_GPOS_SEEN) { /* Need to have PL_reg_ganch */
+    if (prog->reganch & ROPT_GPOS_SEEN) { /* Need to set reginfo->ganch */
        MAGIC *mg;
 
        if (flags & REXEC_IGNOREPOS)    /* Means: check only at start */
-           PL_reg_ganch = startpos;
+           reginfo.ganch = startpos;
        else if (sv && SvTYPE(sv) >= SVt_PVMG
                  && SvMAGIC(sv)
                  && (mg = mg_find(sv, PERL_MAGIC_regex_global))
                  && mg->mg_len >= 0) {
-           PL_reg_ganch = strbeg + mg->mg_len; /* Defined pos() */
+           reginfo.ganch = strbeg + mg->mg_len;        /* Defined pos() */
            if (prog->reganch & ROPT_ANCH_GPOS) {
-               if (s > PL_reg_ganch)
+               if (s > reginfo.ganch)
                    goto phooey;
-               s = PL_reg_ganch;
+               s = reginfo.ganch;
            }
        }
        else                            /* pos() not defined */
-           PL_reg_ganch = strbeg;
+           reginfo.ganch = strbeg;
     }
 
     if (!(flags & REXEC_CHECKED) && (prog->check_substr != NULL || prog->check_utf8 != NULL)) {
@@ -1726,34 +1734,12 @@ Perl_regexec_flags(pTHX_ register regexp *prog, char *stringarg, register char *
        }
     }
 
-    DEBUG_EXECUTE_r({
-       const char * const s0   = UTF
-           ? pv_uni_display(dsv0, (U8*)prog->precomp, prog->prelen, 60,
-                         UNI_DISPLAY_REGEX)
-           : prog->precomp;
-       const int len0 = UTF ? SvCUR(dsv0) : prog->prelen;
-       const char * const s1 = do_utf8 ? sv_uni_display(dsv1, sv, 60,
-                                              UNI_DISPLAY_REGEX) : startpos;
-       const int len1 = do_utf8 ? SvCUR(dsv1) : strend - startpos;
-        if (!PL_colorset)
-            reginitcolors();
-        PerlIO_printf(Perl_debug_log,
-                      "%sMatching REx%s \"%s%*.*s%s%s\" against \"%s%.*s%s%s\"\n",
-                      PL_colors[4], PL_colors[5], PL_colors[0],
-                      len0, len0, s0,
-                      PL_colors[1],
-                      len0 > 60 ? "..." : "",
-                      PL_colors[0],
-                      (int)(len1 > 60 ? 60 : len1),
-                      s1, PL_colors[1],
-                      (len1 > 60 ? "..." : "")
-             );
-    });
+
 
     /* Simplest case:  anchored match need be tried only once. */
     /*  [unless only anchor is BOL and multiline is set] */
     if (prog->reganch & (ROPT_ANCH & ~ROPT_ANCH_GPOS)) {
-       if (s == startpos && regtry(prog, startpos))
+       if (s == startpos && regtry(&reginfo, startpos))
            goto got_it;
        else if (multiline || (prog->reganch & ROPT_IMPLICIT)
                 || (prog->reganch & ROPT_ANCH_MBOL)) /* XXXX SBOL? */
@@ -1768,7 +1754,7 @@ Perl_regexec_flags(pTHX_ register regexp *prog, char *stringarg, register char *
                if (s == startpos)
                    goto after_try;
                while (1) {
-                   if (regtry(prog, s))
+                   if (regtry(&reginfo, s))
                        goto got_it;
                  after_try:
                    if (s >= end)
@@ -1786,15 +1772,19 @@ Perl_regexec_flags(pTHX_ register regexp *prog, char *stringarg, register char *
                    s--;
                while (s < end) {
                    if (*s++ == '\n') { /* don't need PL_utf8skip here */
-                       if (regtry(prog, s))
+                       if (regtry(&reginfo, s))
                            goto got_it;
                    }
                }               
            }
        }
        goto phooey;
-    } else if (prog->reganch & ROPT_ANCH_GPOS) {
-       if (regtry(prog, PL_reg_ganch))
+    } else if (ROPT_GPOS_CHECK == (prog->reganch & ROPT_GPOS_CHECK)) 
+    {
+        /* the warning about reginfo.ganch being used without intialization
+           is bogus -- we set it above, when prog->reganch & ROPT_GPOS_SEEN 
+           and we only enter this block when the same bit is set. */
+       if (regtry(&reginfo, reginfo.ganch))
            goto got_it;
        goto phooey;
     }
@@ -1812,28 +1802,26 @@ Perl_regexec_flags(pTHX_ register regexp *prog, char *stringarg, register char *
        ch = SvPVX_const(do_utf8 ? prog->anchored_utf8 : prog->anchored_substr)[0];
 
        if (do_utf8) {
-           while (s < strend) {
+           REXEC_FBC_SCAN(
                if (*s == ch) {
                    DEBUG_EXECUTE_r( did_match = 1 );
-                   if (regtry(prog, s)) goto got_it;
+                   if (regtry(&reginfo, s)) goto got_it;
                    s += UTF8SKIP(s);
                    while (s < strend && *s == ch)
                        s += UTF8SKIP(s);
                }
-               s += UTF8SKIP(s);
-           }
+           );
        }
        else {
-           while (s < strend) {
+           REXEC_FBC_SCAN(
                if (*s == ch) {
                    DEBUG_EXECUTE_r( did_match = 1 );
-                   if (regtry(prog, s)) goto got_it;
+                   if (regtry(&reginfo, s)) goto got_it;
                    s++;
                    while (s < strend && *s == ch)
                        s++;
                }
-               s++;
-           }
+           );
        }
        DEBUG_EXECUTE_r(if (!did_match)
                PerlIO_printf(Perl_debug_log,
@@ -1864,14 +1852,19 @@ Perl_regexec_flags(pTHX_ register regexp *prog, char *stringarg, register char *
            back_max = prog->float_max_offset;
            back_min = prog->float_min_offset;
        }
+       
+           
        if (must == &PL_sv_undef)
            /* could not downgrade utf8 check substring, so must fail */
            goto phooey;
 
-       last = HOP3c(strend,    /* Cannot start after this */
-                         -(I32)(CHR_SVLEN(must)
-                                - (SvTAIL(must) != 0) + back_min), strbeg);
-
+        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
@@ -1884,9 +1877,9 @@ Perl_regexec_flags(pTHX_ register regexp *prog, char *stringarg, register char *
        strend = HOPc(strend, -dontbother);
        while ( (s <= last) &&
                ((flags & REXEC_SCREAM)
-                ? (s = screaminstr(sv, must, HOP3c(s, back_min, strend) - strbeg,
+                ? (s = screaminstr(sv, must, HOP3c(s, back_min, (back_min<0 ? strbeg : strend)) - strbeg,
                                    end_shift, &scream_pos, 0))
-                : (s = fbm_instr((unsigned char*)HOP3(s, back_min, strend),
+                : (s = fbm_instr((unsigned char*)HOP3(s, back_min, (back_min<0 ? strbeg : strend)),
                                  (unsigned char*)strend, must,
                                  multiline ? FBMrf_MULTILINE : 0))) ) {
            /* we may be pointing at the wrong string */
@@ -1898,69 +1891,58 @@ Perl_regexec_flags(pTHX_ register regexp *prog, char *stringarg, register char *
                s = HOPc(s, -back_max);
            }
            else {
-               char *t = (last1 >= PL_bostr) ? HOPc(last1, 1) : last1 + 1;
+               char * const t = (last1 >= PL_bostr) ? HOPc(last1, 1) : last1 + 1;
 
                last1 = HOPc(s, -back_min);
-               s = t;          
+               s = t;
            }
            if (do_utf8) {
                while (s <= last1) {
-                   if (regtry(prog, s))
+                   if (regtry(&reginfo, s))
                        goto got_it;
                    s += UTF8SKIP(s);
                }
            }
            else {
                while (s <= last1) {
-                   if (regtry(prog, s))
+                   if (regtry(&reginfo, s))
                        goto got_it;
                    s++;
                }
            }
        }
-       DEBUG_EXECUTE_r(if (!did_match)
-                    PerlIO_printf(Perl_debug_log, 
-                                  "Did not find %s substr \"%s%.*s%s\"%s...\n",
+       DEBUG_EXECUTE_r(if (!did_match) {
+            RE_PV_QUOTED_DECL(quoted, do_utf8, 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"),
-                             PL_colors[0],
-                             (int)(SvCUR(must) - (SvTAIL(must)!=0)),
-                             SvPVX_const(must),
-                                  PL_colors[1], (SvTAIL(must) ? "$" : ""))
-               );
+                quoted, RE_SV_TAIL(must));
+        });                
        goto phooey;
     }
-    else if ((c = prog->regstclass)) {
+    else if ( (c = prog->regstclass) ) {
        if (minlen) {
-           I32 op = (U8)OP(prog->regstclass);
+           const OPCODE op = OP(prog->regstclass);
            /* don't bother with what can't match */
-           if (PL_regkind[op] != EXACT && op != CANY)
+           if (PL_regkind[op] != EXACT && op != CANY && PL_regkind[op] != TRIE)
                strend = HOPc(strend, -(minlen - 1));
        }
        DEBUG_EXECUTE_r({
-           SV *prop = sv_newmortal();
-           const char *s0;
-           const char *s1;
-           int len0;
-           int len1;
-
-           regprop(prop, c);
-           s0 = UTF ?
-             pv_uni_display(dsv0, (U8*)SvPVX_const(prop), SvCUR(prop), 60,
-                            UNI_DISPLAY_REGEX) :
-             SvPVX_const(prop);
-           len0 = UTF ? SvCUR(dsv0) : SvCUR(prop);
-           s1 = UTF ?
-             sv_uni_display(dsv1, sv, 60, UNI_DISPLAY_REGEX) : s;
-           len1 = UTF ? SvCUR(dsv1) : strend - s;
-           PerlIO_printf(Perl_debug_log,
-                         "Matching stclass \"%*.*s\" against \"%*.*s\"\n",
-                         len0, len0, s0,
-                         len1, len1, s1);
+           SV * const prop = sv_newmortal();
+           regprop(prog, prop, c);
+           {
+               RE_PV_QUOTED_DECL(quoted,UTF,PERL_DEBUG_PAD_ZERO(1),
+                   s,strend-s,60);
+               PerlIO_printf(Perl_debug_log,
+                   "Matching stclass %.*s against %s (%d chars)\n",
+                   (int)SvCUR(prop), SvPVX_const(prop),
+                    quoted, (int)(strend - s));
+           }
        });
-        if (find_byclass(prog, c, s, strend, 0))
+        if (find_byclass(prog, c, s, strend, &reginfo))
            goto got_it;
-       DEBUG_EXECUTE_r(PerlIO_printf(Perl_debug_log, "Contradicts stclass...\n"));
+       DEBUG_EXECUTE_r(PerlIO_printf(Perl_debug_log, "Contradicts stclass... [regexec_flags]\n"));
     }
     else {
        dontbother = 0;
@@ -2003,9 +1985,10 @@ Perl_regexec_flags(pTHX_ register regexp *prog, char *stringarg, register char *
                }
            }
            if (last == NULL) {
-               DEBUG_EXECUTE_r(PerlIO_printf(Perl_debug_log,
-                                     "%sCan't trim the tail, match fails (should not happen)%s\n",
-                                     PL_colors[4], PL_colors[5]));
+               DEBUG_EXECUTE_r(
+                   PerlIO_printf(Perl_debug_log,
+                       "%sCan't trim the tail, match fails (should not happen)%s\n",
+                       PL_colors[4], PL_colors[5]));
                goto phooey; /* Should not happen! */
            }
            dontbother = strend - last + prog->float_min_offset;
@@ -2016,7 +1999,7 @@ Perl_regexec_flags(pTHX_ register regexp *prog, char *stringarg, register char *
        /* We don't know much -- general case. */
        if (do_utf8) {
            for (;;) {
-               if (regtry(prog, s))
+               if (regtry(&reginfo, s))
                    goto got_it;
                if (s >= strend)
                    break;
@@ -2025,7 +2008,7 @@ Perl_regexec_flags(pTHX_ register regexp *prog, char *stringarg, register char *
        }
        else {
            do {
-               if (regtry(prog, s))
+               if (regtry(&reginfo, s))
                    goto got_it;
            } while (s++ < strend);
        }
@@ -2043,14 +2026,16 @@ got_it:
            sv_setsv(oreplsv, GvSV(PL_replgv));/* So that when GvSV(replgv) is
                                                  restored, the value remains
                                                  the same. */
-       restore_pos(aTHX_ 0);
+       restore_pos(aTHX_ prog);
     }
+    if (prog->paren_names) 
+        (void)hv_iterinit(prog->paren_names);
 
     /* make sure $`, $&, $', and $digit will work later */
     if ( !(flags & REXEC_NOT_FIRST) ) {
        RX_MATCH_COPY_FREE(prog);
        if (flags & REXEC_COPY_STR) {
-           I32 i = PL_regeol - startpos + (stringarg - strbeg);
+           const I32 i = PL_regeol - startpos + (stringarg - strbeg);
 #ifdef PERL_OLD_COPY_ON_WRITE
            if ((SvIsCOW(sv)
                 || (SvFLAGS(sv) & CAN_COW_MASK) == CAN_COW_FLAGS)) {
@@ -2083,26 +2068,24 @@ phooey:
     DEBUG_EXECUTE_r(PerlIO_printf(Perl_debug_log, "%sMatch failed%s\n",
                          PL_colors[4], PL_colors[5]));
     if (PL_reg_eval_set)
-       restore_pos(aTHX_ 0);
+       restore_pos(aTHX_ prog);
     return 0;
 }
 
+
 /*
  - regtry - try match at specific point
  */
 STATIC I32                     /* 0 failure, 1 success */
-S_regtry(pTHX_ regexp *prog, char *startpos)
+S_regtry(pTHX_ const regmatch_info *reginfo, char *startpos)
 {
     dVAR;
-    register I32 i;
     register I32 *sp;
     register I32 *ep;
     CHECKPOINT lastcp;
+    regexp *prog = reginfo->prog;
     GET_RE_DEBUG_FLAGS_DECL;
 
-#ifdef DEBUGGING
-    PL_regindent = 0;  /* XXXX Not good when matches are reenterable... */
-#endif
     if ((prog->reganch & ROPT_EVAL_SEEN) && !PL_reg_eval_set) {
        MAGIC *mg;
 
@@ -2111,7 +2094,7 @@ S_regtry(pTHX_ regexp *prog, char *startpos)
            PerlIO_printf(Perl_debug_log, "  setting stack tmpbase at %"IVdf"\n",
                          (IV)(PL_stack_sp - PL_stack_base));
            ));
-       SAVEI32(cxstack[cxstack_ix].blk_oldsp);
+       SAVESTACK_CXPOS();
        cxstack[cxstack_ix].blk_oldsp = PL_stack_sp - PL_stack_base;
        /* Otherwise OP_NEXTSTATE will free whatever on stack now.  */
        SAVETMPS;
@@ -2119,33 +2102,33 @@ S_regtry(pTHX_ regexp *prog, char *startpos)
        /* SAVEI8(cxstack[cxstack_ix].blk_gimme);
           cxstack[cxstack_ix].blk_gimme = G_SCALAR; */
 
-       if (PL_reg_sv) {
+       if (reginfo->sv) {
            /* Make $_ available to executed code. */
-           if (PL_reg_sv != DEFSV) {
+           if (reginfo->sv != DEFSV) {
                SAVE_DEFSV;
-               DEFSV = PL_reg_sv;
+               DEFSV = reginfo->sv;
            }
        
-           if (!(SvTYPE(PL_reg_sv) >= SVt_PVMG && SvMAGIC(PL_reg_sv)
-                 && (mg = mg_find(PL_reg_sv, PERL_MAGIC_regex_global)))) {
+           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(sv))
                    sv_force_normal_flags(sv, 0);
 #endif
-               mg = sv_magicext(PL_reg_sv, (SV*)0, PERL_MAGIC_regex_global,
+               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, 0);
+           SAVEDESTRUCTOR_X(restore_pos, prog);
         }
         if (!PL_reg_curpm) {
            Newxz(PL_reg_curpm, 1, PMOP);
 #ifdef USE_ITHREADS
             {
-                SV* repointer = newSViv(0);
+               SV* const repointer = newSViv(0);
                 /* so we know which PL_regex_padav element is PL_reg_curpm */
                 SvFLAGS(repointer) |= SVf_BREAK;
                 av_push(PL_regex_padav,repointer);
@@ -2173,16 +2156,16 @@ S_regtry(pTHX_ regexp *prog, char *startpos)
        prog->subbeg = PL_bostr;
        prog->sublen = PL_regeol - PL_bostr; /* strend may have been modified */
     }
+    DEBUG_EXECUTE_r(PL_reg_starttry = startpos);
     prog->startp[0] = startpos - PL_bostr;
     PL_reginput = startpos;
-    PL_regstartp = prog->startp;
-    PL_regendp = prog->endp;
     PL_reglastparen = &prog->lastparen;
     PL_reglastcloseparen = &prog->lastcloseparen;
     prog->lastparen = 0;
     prog->lastcloseparen = 0;
     PL_regsize = 0;
-    DEBUG_EXECUTE_r(PL_reg_starttry = startpos);
+    PL_regstartp = prog->startp;
+    PL_regendp = prog->endp;
     if (PL_reg_start_tmpl <= prog->nparens) {
        PL_reg_start_tmpl = prog->nparens*3/2 + 3;
         if(PL_reg_start_tmp)
@@ -2209,6 +2192,7 @@ S_regtry(pTHX_ regexp *prog, char *startpos)
     sp = prog->startp;
     ep = prog->endp;
     if (prog->nparens) {
+       register I32 i;
        for (i = prog->nparens; i > (I32)*PL_reglastparen; i--) {
            *++sp = -1;
            *++ep = -1;
@@ -2216,7 +2200,7 @@ S_regtry(pTHX_ regexp *prog, char *startpos)
     }
 #endif
     REGCP_SET(lastcp);
-    if (regmatch(prog->program + 1)) {
+    if (regmatch(reginfo, prog->program + 1)) {
        prog->endp[0] = PL_reginput - PL_bostr;
        return 1;
     }
@@ -2224,319 +2208,402 @@ S_regtry(pTHX_ regexp *prog, char *startpos)
     return 0;
 }
 
-#define RE_UNWIND_BRANCH       1
-#define RE_UNWIND_BRANCHJ      2
-
-union re_unwind_t;
-
-typedef struct {               /* XX: makes sense to enlarge it... */
-    I32 type;
-    I32 prev;
-    CHECKPOINT lastcp;
-} re_unwind_generic_t;
-
-typedef struct {
-    I32 type;
-    I32 prev;
-    CHECKPOINT lastcp;
-    I32 lastparen;
-    regnode *next;
-    char *locinput;
-    I32 nextchr;
-#ifdef DEBUGGING
-    int regindent;
-#endif
-} re_unwind_branch_t;
-
-typedef union re_unwind_t {
-    I32 type;
-    re_unwind_generic_t generic;
-    re_unwind_branch_t branch;
-} re_unwind_t;
 
 #define sayYES goto yes
 #define sayNO goto no
-#define sayNO_ANYOF goto no_anyof
-#define sayYES_FINAL goto yes_final
-#define sayYES_LOUD  goto yes_loud
-#define sayNO_FINAL  goto no_final
-#define sayNO_SILENT goto do_no
-#define saySAME(x) if (x) goto yes; else goto no
-
-#define POSCACHE_SUCCESS 0     /* caching success rather than failure */
-#define POSCACHE_SEEN 1                /* we know what we're caching */
-#define POSCACHE_START 2       /* the real cache: this bit maps to pos 0 */
-#define CACHEsayYES STMT_START { \
-    if (cache_offset | cache_bit) { \
-       if (!(PL_reg_poscache[0] & (1<<POSCACHE_SEEN))) \
-           PL_reg_poscache[0] |= (1<<POSCACHE_SUCCESS) || (1<<POSCACHE_SEEN); \
-        else if (!(PL_reg_poscache[0] & (1<<POSCACHE_SUCCESS))) { \
-           /* cache records failure, but this is success */ \
-           DEBUG_r( \
-               PerlIO_printf(Perl_debug_log, \
-                   "%*s  (remove success from failure cache)\n", \
-                   REPORT_CODE_OFF+PL_regindent*2, "") \
-           ); \
-           PL_reg_poscache[cache_offset] &= ~(1<<cache_bit); \
-       } \
-    } \
-    sayYES; \
-} STMT_END
-#define CACHEsayNO STMT_START { \
-    if (cache_offset | cache_bit) { \
-       if (!(PL_reg_poscache[0] & (1<<POSCACHE_SEEN))) \
-           PL_reg_poscache[0] |= (1<<POSCACHE_SEEN); \
-        else if ((PL_reg_poscache[0] & (1<<POSCACHE_SUCCESS))) { \
-           /* cache records success, but this is failure */ \
-           DEBUG_r( \
-               PerlIO_printf(Perl_debug_log, \
-                   "%*s  (remove failure from success cache)\n", \
-                   REPORT_CODE_OFF+PL_regindent*2, "") \
-           ); \
-           PL_reg_poscache[cache_offset] &= ~(1<<cache_bit); \
-       } \
-    } \
-    sayNO; \
-} STMT_END
+#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. Currently 29 makes these messages line
-   up with the opcode they refer to. Earlier perls used 25 which
-   left these messages outdented making reviewing a debug output
-   quite difficult.
+   'failed...' are printed. It should be set such that messages 
+   are inline with the regop output that created them.
 */
-#define REPORT_CODE_OFF 29
+#define REPORT_CODE_OFF 32
 
 
 /* Make sure there is a test for this +1 options in re_tests */
 #define TRIE_INITAL_ACCEPT_BUFFLEN 4;
 
+#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 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
+    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) \
+    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) \
+    scan = node; \
+    st->resume_state = state; \
+    goto push_yes_state;
 
-/* simulate a recursive call to regmatch */
-
-#define REGMATCH(ns, where) \
-    new_scan = (ns); \
-    resume_state = resume_##where; \
-    goto start_recurse; \
-    resume_point_##where:
-
-typedef enum {
-    resume_TRIE1,
-    resume_TRIE2,
-    resume_CURLYX,
-    resume_WHILEM1,
-    resume_WHILEM2,
-    resume_WHILEM3,
-    resume_WHILEM4,
-    resume_WHILEM5,
-    resume_WHILEM6,
-    resume_CURLYM1,
-    resume_CURLYM2,
-    resume_CURLYM3,
-    resume_CURLYM4,
-    resume_IFMATCH,
-    resume_PLUS1,
-    resume_PLUS2,
-    resume_PLUS3,
-    resume_PLUS4,
-    resume_END
-} resume_states;
-
-
-struct regmatch_state {
-    struct regmatch_state *prev_state;
-    resume_states resume_state;
-    regnode *scan;
-    regnode *next;
-    bool minmod;
-    bool sw;
-    int logical;
-    I32 unwind;
-    CURCUR *cc;
-    char *locinput;
 
-    I32 n;
-    I32 ln;
-    I32 c1, c2, paren;
-    CHECKPOINT cp, lastcp;
-    CURCUR *oldcc;
-    char *lastloc;
-    I32 cache_offset, cache_bit;
-    I32 curlym_l;
-    I32 matches;
-    I32 maxwanted;
-    char *e; 
-    char *old;
-    int count;
-    re_cc_state *cur_call_cc;
-    regexp *end_re;
-    reg_trie_accepted *accept_buff;
-    U32 accepted;
-
-    re_cc_state *reg_call_cc;  /* saved value of PL_reg_call_cc */
-};
 
 /*
- - regmatch - main matching routine
- *
- * Conceptually the strategy is simple:  check to see whether the current
- * node matches, call self recursively to see whether the rest matches,
- * and then act accordingly.  In practice we make some effort to avoid
- * recursion, in particular by going through "ordinary" nodes (that don't
- * need to know whether the rest of the match failed) by a loop instead of
- * by recursion.
- */
-/* [lwall] I've hoisted the register declarations to the outer block in order to
- * maybe save a little bit of pushing and popping on the stack.  It also takes
- * advantage of machines that use a register save mask on subroutine entry.
- *
- * This function used to be heavily recursive, but since this had the
- * effect of blowing the CPU stack on complex regexes, it has been
- * restructured to be iterative, and to save state onto the heap rather
- * than the stack. Essentially whereever regmatch() used to be called, it
- * pushes the current state, notes where to return, then jumps back into
- * the main loop.
- *
- * Originally the structure of this function used to look something like
 
-    S_regmatch() {
-       int a = 1, b = 2;
+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
        ...
-       while (scan != NULL) {
-           ...
-           switch (OP(scan)) {
-               case FOO: {
-                   int local = 3;
-                   ...
-                   if (regmatch(...))  // recurse
-                       goto yes;
-               }
-               ...
-           }
-       }
-       yes:
-       return 1;
-    }
+       // 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);
+       // 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;
 
- * Now it looks something like this:
+    case IFMATCH_A_fail: // A failed, so the assertion failed
+       ...;   // do some housekeeping, then ...
+       sayNO; // propagate the failure
 
-    struct regmatch_state {
-       int a, b, local;
-       int resume_state;
-    };
+#undef ST
 
-    S_regmatch() {
-       int a = 1, b = 2;
-       int local;
+    ...
+    }
+
+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 = ...
        ...
-       while (scan != NULL) {
-           ...
-           switch (OP(scan)) {
-               case FOO: {
-                   local = 3;
-                   ...
-                   resume_state = resume_FOO;
-                   new_scan = ...;
-                   goto start_recurse;
-                   resume_point_FOO:
-
-                   if (result)  // recurse
-                       goto yes;
-               }
-               ...
-           }
-           start_recurse:
-           ...push a, b, local onto the heap
-           a = 1; b = 2;
-           scan = new_scan;
-       }
-       yes:
-       result = 1;
-       if (states pushed on heap) {
-           ... restore a, b, local from heap
-           switch (resume_state) {
-           case resume_FOO:
-               goto resume_point_FOO;
-           ...
-           }
+       if (regmatch(A)) {
+           next = B;
+           bar = foo;
+           break;
        }
-       return result
+       ...;   // do some housekeeping, then ...
+       sayNO; // propagate the failure
     }
-           
- * WARNING: this means that any line in this function that contains a
- * REGMATCH() or TRYPAREN() is actually simulating a recursive call to
- * regmatch() using gotos instead. Thus the values of any local variables
- * not saved in the regmatch_state structure will have been lost when
- * execution resumes on the next line .
- */
+
+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);
+       PUSH_YES_STATE_GOTO(resume_state, node);
+
+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.
  
+Bascktrack 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, do_utf8);             \
+       PerlIO_printf(Perl_debug_log,                       \
+           "    %*s"pp" %s\n",                             \
+           depth*2, "",                                    \
+           reg_name[st->resume_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 do_utf8, 
+    const char *start, const char *end, const char *blurb)
+{
+    const bool utf8_pat= prog->reganch & ROPT_UTF8 ? 1 : 0;
+    if (!PL_colorset)   
+            reginitcolors();    
+    {
+        RE_PV_QUOTED_DECL(s0, utf8_pat, PERL_DEBUG_PAD_ZERO(0), 
+            prog->precomp, prog->prelen, 60);   
+        
+        RE_PV_QUOTED_DECL(s1, do_utf8, 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 (do_utf8||utf8_pat) 
+            PerlIO_printf(Perl_debug_log, "UTF-8 %s%s%s...\n",
+                utf8_pat ? "pattern" : "",
+                utf8_pat && do_utf8 ? " and " : "",
+                do_utf8 ? "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 do_utf8)
+{
+    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;
+
+    while (do_utf8 && 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 (do_utf8 && 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 = (do_utf8 && 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;
+    SV *sv_dat=(SV*)rex->data->data[ ARG( scan ) ];
+    I32 *nums=(I32*)SvPVX(sv_dat);
+    for ( n=0; n<SvIVX(sv_dat); n++ ) {
+        if ((I32)*PL_reglastparen >= nums[n] &&
+            PL_regendp[nums[n]] != -1)
+        {
+            return nums[n];
+        }
+    }
+    return 0;
+}
 
 STATIC I32                     /* 0 failure, 1 success */
-S_regmatch(pTHX_ regnode *prog)
+S_regmatch(pTHX_ const regmatch_info *reginfo, regnode *prog)
 {
+#if PERL_VERSION < 9
+    dMY_CXT;
+#endif
     dVAR;
     register const bool do_utf8 = PL_reg_match_utf8;
-    const U32 uniflags = ckWARN(WARN_UTF8) ? 0 : UTF8_ALLOW_ANY;
-
-    /************************************************************
-     * the following variabes are saved and restored on each fake
-     * recursive call to regmatch:
-     *
-     * The first ones contain state that needs to be maintained
-     * across the main while loop: */
-
-    struct regmatch_state *prev_state = NULL; /* stack of pushed states */
-    resume_states resume_state; /* where to jump to on return */
-    register regnode *scan;    /* Current node. */
-    regnode *next;             /* Next node. */
-    bool minmod = 0;           /* the next {n.m} is a {n,m}? */
-    bool sw = 0;               /* the condition value in (?(cond)a|b) */
-    int logical = 0;
-    I32 unwind = 0;            /* savestack index of current unwind block */
-    CURCUR *cc = NULL;         /* current innermost curly struct */
-    register char *locinput = PL_reginput;
+    const U32 uniflags = UTF8_ALLOW_DEFAULT;
+
+    regexp *rex = reginfo->prog;
 
-    /* while the rest of these are local to an individual branch, and
-     * have only been hoisted into this outer scope to allow for saving and
-     * restoration - thus they can be safely reused in other branches.
-     * Note that they are only initialized here to silence compiler
-     * warnings :-( */
-
-    register I32 n = 0;                /* no or next */
-    register I32 ln = 0;       /* len or last */
-    register I32 c1 = 0, c2 = 0, paren = 0; /* case fold search, parenth */
-    CHECKPOINT cp = 0;         /* remember current savestack indexes */
-    CHECKPOINT lastcp = 0;
-    CURCUR *oldcc = NULL;      /* tmp copy of cc */
-    char *lastloc = NULL;      /* Detection of 0-len. */
-    I32 cache_offset = 0;
-    I32 cache_bit = 0;
-    I32 curlym_l = 0;
-    I32 matches = 0;
-    I32 maxwanted = 0;
-    char *e = NULL;
-    char *old = NULL;
-    int count = 0;
-    re_cc_state *cur_call_cc = NULL;
-    regexp *end_re = NULL;
-    reg_trie_accepted *accept_buff = NULL;
-    U32 accepted = 0; /* how many accepting states we have seen */
-
-    /************************************************************
-     * these variables are NOT saved: */
+    regmatch_slab  *orig_slab;
+    regmatch_state *orig_state;
 
+    /* the current state. This is a cached copy of PL_regmatch_state */
+    register regmatch_state *st;
+
+    /* cache heavy used fields of st in registers */
+    register regnode *scan;
+    register regnode *next;
+    register I32 n = 0;        /* general value; init to avoid compiler warning */
+    register I32 ln = 0; /* len or last;  init to avoid compiler warning */
+    register char *locinput = PL_reginput;
     register I32 nextchr;   /* is always set to UCHARAT(locinput) */
-    regnode *new_scan; /* node to begin exedcution at when recursing */
-    bool result;       /* return value of S_regmatch */
 
-    regnode *inner;    /* Next node in internal branch. */
-    
+    bool result = 0;       /* return value of S_regmatch */
+    int depth = 0;         /* depth of backtrack stack */
+    int nochange_depth = 0; /* depth of RECURSE recursion with nochange*/
+    regmatch_state *yes_state = NULL; /* state to pop to on success of
+                                                           subpattern */
+    regmatch_state *cur_eval = NULL; /* most recent EVAL_AB state */
+    struct regmatch_state  *cur_curlyx = NULL; /* most recent curlyx */
+    U32 state_num;
+
+    /* 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))
+                           */
+
 #ifdef DEBUGGING
-    SV *re_debug_flags = NULL;
-    GET_RE_DEBUG_FLAGS;
-    PL_regindent++;
+    GET_RE_DEBUG_FLAGS_DECL;
 #endif
 
+    /* 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);
+    }
+
+    /* remember current high-water mark for exit */
+    /* XXX this should be done with SAVE* instead */
+    orig_slab  = PL_regmatch_slab;
+    orig_state = 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 */
     nextchr = UCHARAT(locinput);
     scan = prog;
@@ -2544,79 +2611,29 @@ S_regmatch(pTHX_ regnode *prog)
 
         DEBUG_EXECUTE_r( {
            SV * const prop = sv_newmortal();
-           const int docolor = *PL_colors[0];
-           const int taill = (docolor ? 10 : 7); /* 3 chars for "> <" */
-           int l = (PL_regeol - locinput) > taill ? taill : (PL_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 - PL_bostr) > (5 + taill) - l
-               ? (5 + taill) - l : locinput - PL_bostr;
-           int pref0_len;
-
-           while (do_utf8 && UTF8_IS_CONTINUATION(*(U8*)(locinput - pref_len)))
-               pref_len++;
-           pref0_len = pref_len  - (locinput - PL_reg_starttry);
-           if (l + pref_len < (5 + taill) && l < PL_regeol - locinput)
-               l = ( PL_regeol - locinput > (5 + taill) - pref_len
-                     ? (5 + taill) - pref_len : PL_regeol - locinput);
-           while (do_utf8 && UTF8_IS_CONTINUATION(*(U8*)(locinput + l)))
-               l--;
-           if (pref0_len < 0)
-               pref0_len = 0;
-           if (pref0_len > pref_len)
-               pref0_len = pref_len;
-           regprop(prop, scan);
-           {
-             const char * const s0 =
-               do_utf8 && OP(scan) != CANY ?
-               pv_uni_display(PERL_DEBUG_PAD(0), (U8*)(locinput - pref_len),
-                              pref0_len, 60, UNI_DISPLAY_REGEX) :
-               locinput - pref_len;
-             const int len0 = do_utf8 ? strlen(s0) : pref0_len;
-             const char * const s1 = do_utf8 && OP(scan) != CANY ?
-               pv_uni_display(PERL_DEBUG_PAD(1),
-                              (U8*)(locinput - pref_len + pref0_len),
-                              pref_len - pref0_len, 60, UNI_DISPLAY_REGEX) :
-               locinput - pref_len + pref0_len;
-             const int len1 = do_utf8 ? strlen(s1) : pref_len - pref0_len;
-             const char * const s2 = do_utf8 && OP(scan) != CANY ?
-               pv_uni_display(PERL_DEBUG_PAD(2), (U8*)locinput,
-                              PL_regeol - locinput, 60, UNI_DISPLAY_REGEX) :
-               locinput;
-             const int len2 = do_utf8 ? strlen(s2) : l;
-             PerlIO_printf(Perl_debug_log,
-                           "%4"IVdf" <%s%.*s%s%s%.*s%s%s%s%.*s%s>%*s|%3"IVdf":%*s%s\n",
-                           (IV)(locinput - PL_bostr),
-                           PL_colors[4],
-                           len0, s0,
-                           PL_colors[5],
-                           PL_colors[2],
-                           len1, s1,
-                           PL_colors[3],
-                           (docolor ? "" : "> <"),
-                           PL_colors[0],
-                           len2, s2,
-                           PL_colors[1],
-                           15 - l - pref_len + 1,
-                           "",
-                           (IV)(scan - PL_regprogram), PL_regindent*2, "",
-                           SvPVX_const(prop));
-           }
+           regnode *rnext=regnext(scan);
+           DUMP_EXEC_POS( locinput, scan, do_utf8 );
+           regprop(rex, prop, scan);
+            
+           PerlIO_printf(Perl_debug_log,
+                   "%3"IVdf":%*s%s(%"IVdf")\n",
+                   (IV)(scan - rex->program), depth*2, "",
+                   SvPVX_const(prop),
+                   (PL_regkind[OP(scan)] == END || !rnext) ? 
+                       0 : (IV)(rnext - rex->program));
        });
 
        next = scan + NEXT_OFF(scan);
        if (next == scan)
            next = NULL;
+       state_num = OP(scan);
 
-       switch (OP(scan)) {
+      reenter_switch:
+       switch (state_num) {
        case BOL:
            if (locinput == PL_bostr)
            {
-               /* regtill = regbol; */
+               /* reginfo->till = reginfo->bol; */
                break;
            }
            sayNO;
@@ -2632,7 +2649,7 @@ S_regmatch(pTHX_ regnode *prog)
                break;
            sayNO;
        case GPOS:
-           if (locinput == PL_reg_ganch)
+           if (locinput == reginfo->ganch)
                break;
            sayNO;
        case EOL:
@@ -2682,117 +2699,137 @@ S_regmatch(pTHX_ regnode *prog)
                nextchr = UCHARAT(++locinput);
            break;
 
-
-
-       /*
-          traverse the TRIE keeping track of all accepting states
-          we transition through until we get to a failing node.
-
-
-       */
+#undef  ST
+#define ST st->u.trie
+        case TRIEC:
+            /* In this case the charclass data is available inline so
+               we can fail fast without a lot of extra overhead. 
+             */
+            if (scan->flags == EXACT || !do_utf8) {
+                if(!ANYOF_BITMAP_TEST(scan, *locinput)) {
+                    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;
+                    /* NOTREACHED */
+                }                      
+            }
+            /* FALL THROUGH */
        case TRIE:
-       case TRIEF:
-       case TRIEFL:
            {
+                /* what type of TRIE am I? (utf8 makes this contextual) */
+               const enum { trie_plain, trie_utf8, trie_utf8_fold }
+                   trie_type = do_utf8 ?
+                         (scan->flags == EXACT ? trie_utf8 : trie_utf8_fold)
+                       : trie_plain;
+
+                /* what trie are we using right now */
+               reg_trie_data * const trie
+                   = (reg_trie_data*)rex->data->data[ ARG( scan ) ];
+                U32 state = trie->startstate;
+
+               if (trie->bitmap && trie_type != trie_utf8_fold &&
+                   !TRIE_BITMAP_TEST(trie,*locinput)
+               ) {
+                   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])
+                        );
+                       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;
-               U32 state = 1;
-               U16 charid = 0;
-               U32 base = 0;
-               UV uvc = 0;
+
                STRLEN len = 0;
                STRLEN foldlen = 0;
                U8 *uscan = (U8*)NULL;
                STRLEN bufflen=0;
                SV *sv_accept_buff = NULL;
-               const enum { trie_plain, trie_utf8, trie_uft8_fold }
-                   trie_type = do_utf8 ?
-                         (OP(scan) == TRIE ? trie_utf8 : trie_uft8_fold)
-                       : trie_plain;
+               U8 foldbuf[ UTF8_MAXBYTES_CASE + 1 ];
 
-               reg_trie_data *trie; /* what trie are we using right now */
+               ST.accepted = 0; /* how many accepting states we have seen */
+               ST.B = next;
+               ST.jump = trie->jump;
+               
+#ifdef DEBUGGING
+               ST.me = scan;
+#endif
+                
+               
 
-               accepted = 0; /* how many accepting states we have seen */
-               result = 0;
-               trie = (reg_trie_data*)PL_regdata->data[ ARG( scan ) ];
+               /*
+                  traverse the TRIE keeping track of all accepting states
+                  we transition through until we get to a failing node.
+               */
 
                while ( state && uc <= (U8*)PL_regeol ) {
-
-                   if (trie->states[ state ].wordnum) {
-                       if (!accepted ) {
+                    U32 base = trie->states[ state ].trans.base;
+                    UV uvc = 0;
+                    U16 charid;
+                    /* We use charid to hold the wordnum as we don't use it
+                       for charid until after we have done the wordnum logic. 
+                       We define an alias just so that the wordnum logic reads
+                       more naturally. */
+
+#define got_wordnum charid
+                    got_wordnum = trie->states[ state ].wordnum;
+
+                   if ( got_wordnum ) {
+                       if ( ! ST.accepted ) {
                            ENTER;
                            SAVETMPS;
                            bufflen = TRIE_INITAL_ACCEPT_BUFFLEN;
                            sv_accept_buff=newSV(bufflen *
                                            sizeof(reg_trie_accepted) - 1);
-                           SvCUR_set(sv_accept_buff,
-                                               sizeof(reg_trie_accepted));
+                           SvCUR_set(sv_accept_buff, 0);
                            SvPOK_on(sv_accept_buff);
                            sv_2mortal(sv_accept_buff);
-                           accept_buff =
+                           SAVETMPS;
+                           ST.accept_buff =
                                (reg_trie_accepted*)SvPV_nolen(sv_accept_buff );
                        }
-                       else {
-                           if (accepted >= bufflen) {
+                       do {
+                           if (ST.accepted >= bufflen) {
                                bufflen *= 2;
-                               accept_buff =(reg_trie_accepted*)
+                               ST.accept_buff =(reg_trie_accepted*)
                                    SvGROW(sv_accept_buff,
                                        bufflen * sizeof(reg_trie_accepted));
                            }
                            SvCUR_set(sv_accept_buff,SvCUR(sv_accept_buff)
                                + sizeof(reg_trie_accepted));
-                       }
-                       accept_buff[accepted].wordnum = trie->states[state].wordnum;
-                       accept_buff[accepted].endpos = uc;
-                       ++accepted;
-                   }
 
-                   base = trie->states[ state ].trans.base;
 
-                   DEBUG_TRIE_EXECUTE_r(
+                           ST.accept_buff[ST.accepted].wordnum = got_wordnum;
+                           ST.accept_buff[ST.accepted].endpos = uc;
+                           ++ST.accepted;
+                       } while (trie->nextword && (got_wordnum= trie->nextword[got_wordnum]));
+                   }
+#undef got_wordnum 
+
+                   DEBUG_TRIE_EXECUTE_r({
+                               DUMP_EXEC_POS( (char *)uc, scan, do_utf8 );
                                PerlIO_printf( Perl_debug_log,
-                                   "%*s  %sState: %4"UVxf", Base: %4"UVxf", Accepted: %4"UVxf" ",
-                                   REPORT_CODE_OFF + PL_regindent * 2, "", PL_colors[4],
-                                   (UV)state, (UV)base, (UV)accepted );
-                   );
+                                   "%*s  %sState: %4"UVxf" Accepted: %4"UVxf" ",
+                                   2+depth * 2, "", PL_colors[4],
+                                   (UV)state, (UV)ST.accepted );
+                   });
 
                    if ( base ) {
-                       switch (trie_type) {
-                       case trie_uft8_fold:
-                           if ( foldlen>0 ) {
-                               uvc = utf8n_to_uvuni( uscan, UTF8_MAXLEN, &len, uniflags );
-                               foldlen -= len;
-                               uscan += len;
-                               len=0;
-                           } else {
-                               U8 foldbuf[ UTF8_MAXBYTES_CASE + 1 ];
-                               uvc = utf8n_to_uvuni( (U8*)uc, UTF8_MAXLEN, &len, uniflags );
-                               uvc = to_uni_fold( uvc, foldbuf, &foldlen );
-                               foldlen -= UNISKIP( uvc );
-                               uscan = foldbuf + UNISKIP( uvc );
-                           }
-                           break;
-                       case trie_utf8:
-                           uvc = utf8n_to_uvuni( (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 (trie->widecharmap) {
-                               SV** svpp = (SV**)NULL;
-                               svpp = hv_fetch(trie->widecharmap,
-                                           (char*)&uvc, sizeof(UV), 0);
-                               if (svpp)
-                                   charid = (U16)SvIV(*svpp);
-                           }
-                       }
+                       REXEC_TRIE_READ_CHAR(trie_type, trie, uc, uscan, len,
+                           uvc, charid, foldlen, foldbuf, uniflags);
 
                        if (charid &&
                             (base + charid > trie->uniquecharcount )
@@ -2815,108 +2852,136 @@ S_regmatch(pTHX_ regnode *prog)
                    }
                    DEBUG_TRIE_EXECUTE_r(
                        PerlIO_printf( Perl_debug_log,
-                           "Charid:%3x CV:%4"UVxf" After State: %4"UVxf"%s\n",
+                           "Charid:%3x CP:%4"UVxf" After State: %4"UVxf"%s\n",
                            charid, uvc, (UV)state, PL_colors[5] );
                    );
                }
-               if (!accepted )
+               if (!ST.accepted )
                   sayNO;
 
-           /*
-              There was at least one accepting state that we
-              transitioned through. Presumably the number of accepting
-              states is going to be low, typically one or two. So we
-              simply scan through to find the one with lowest wordnum.
-              Once we find it, we swap the last state into its place
-              and decrement the size. We then try to match the rest of
-              the pattern at the point where the word ends, if we
-              succeed then we end the loop, otherwise the loop
-              eventually terminates once all of the accepting states
-              have been tried.
-           */
+               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] );
+               );
+           }}
 
-               if ( accepted == 1 ) {
-                   DEBUG_EXECUTE_r({
-                        SV **tmp = av_fetch( trie->words, accept_buff[ 0 ].wordnum-1, 0 );
-                               PerlIO_printf( Perl_debug_log,
-                           "%*s  %sonly one match : #%d <%s>%s\n",
-                           REPORT_CODE_OFF+PL_regindent*2, "", PL_colors[4],
-                           accept_buff[ 0 ].wordnum,
-                           tmp ? SvPV_nolen_const( *tmp ) : "not compiled under -Dr",
-                           PL_colors[5] );
-                   });
-                   PL_reginput = (char *)accept_buff[ 0 ].endpos;
-                   /* in this case we free tmps/leave before we call regmatch
-                      as we wont be using accept_buff again. */
-                   FREETMPS;
-                   LEAVE;
-                   REGMATCH(scan + NEXT_OFF(scan), TRIE1);
-                   /*** all unsaved local vars undefined at this point */
-               } else {
-                    DEBUG_EXECUTE_r(
-                        PerlIO_printf( Perl_debug_log,"%*s  %sgot %"IVdf" possible matches%s\n",
-                            REPORT_CODE_OFF + PL_regindent * 2, "", PL_colors[4], (IV)accepted,
-                            PL_colors[5] );
-                    );
-                   while ( !result && accepted-- ) {
-                       U32 best = 0;
-                       U32 cur;
-                       for( cur = 1 ; cur <= accepted ; cur++ ) {
-                           DEBUG_TRIE_EXECUTE_r(
-                               PerlIO_printf( Perl_debug_log,
-                                   "%*s  %sgot %"IVdf" (%d) as best, looking at %"IVdf" (%d)%s\n",
-                                   REPORT_CODE_OFF + PL_regindent * 2, "", PL_colors[4],
-                                   (IV)best, accept_buff[ best ].wordnum, (IV)cur,
-                                   accept_buff[ cur ].wordnum, PL_colors[5] );
-                           );
-
-                           if ( accept_buff[ cur ].wordnum < accept_buff[ best ].wordnum )
-                                   best = cur;
-                       }
-                       DEBUG_EXECUTE_r({
-                           SV ** const tmp = av_fetch( trie->words, accept_buff[ best ].wordnum - 1, 0 );
-                           PerlIO_printf( Perl_debug_log, "%*s  %strying alternation #%d <%s> at 0x%p%s\n",
-                               REPORT_CODE_OFF+PL_regindent*2, "", PL_colors[4],
-                               accept_buff[best].wordnum,
-                               tmp ? SvPV_nolen_const( *tmp ) : "not compiled under -Dr",scan,
-                               PL_colors[5] );
-                       });
-                       if ( best<accepted ) {
-                           reg_trie_accepted tmp = accept_buff[ best ];
-                           accept_buff[ best ] = accept_buff[ accepted ];
-                           accept_buff[ accepted ] = tmp;
-                           best = accepted;
-                       }
-                       PL_reginput = (char *)accept_buff[ best ].endpos;
-
-                        /* 
-                           as far as I can tell we only need the SAVETMPS/FREETMPS 
-                           for re's with EVAL in them but I'm leaving them in for 
-                           all until I can be sure.
-                         */
-                       SAVETMPS;
-                       REGMATCH(scan + NEXT_OFF(scan), TRIE2);
-                       /*** all unsaved local vars undefined at this point */
-                       FREETMPS;
-                   }
-                   FREETMPS;
-                   LEAVE;
-               }
+           /* FALL THROUGH */
+
+       case TRIE_next_fail: /* we failed - try next alterative */
+
+           if ( ST.accepted == 1 ) {
+               /* only one choice left - just continue */
+               DEBUG_EXECUTE_r({
+                   reg_trie_data * const trie
+                       = (reg_trie_data*)rex->data->data[ ARG(ST.me) ];
+                   SV ** const tmp = RX_DEBUG(reginfo->prog)
+                                   ? av_fetch( trie->words, ST.accept_buff[ 0 ].wordnum-1, 0 )
+                                   : NULL;
+                   PerlIO_printf( Perl_debug_log,
+                       "%*s  %sonly one match left: #%d <%s>%s\n",
+                       REPORT_CODE_OFF+depth*2, "", PL_colors[4],
+                       ST.accept_buff[ 0 ].wordnum,
+                       tmp ? SvPV_nolen_const( *tmp ) : "not compiled under -Dr",
+                       PL_colors[5] );
+               });
+               PL_reginput = (char *)ST.accept_buff[ 0 ].endpos;
+               /* in this case we free tmps/leave before we call regmatch
+                  as we wont be using accept_buff again. */
+               FREETMPS;
+               LEAVE;
+               locinput = PL_reginput;
+               nextchr = UCHARAT(locinput);
                
-               if (result) {
-                   sayYES;
-               } else {
-                   sayNO;
+               if ( !ST.jump ) 
+                   scan = ST.B;
+               else
+                   scan = ST.B - ST.jump[ST.accept_buff[0].wordnum];
+               
+               continue; /* execute rest of RE */
+           }
+
+           if (!ST.accepted-- ) {
+               FREETMPS;
+               LEAVE;
+               sayNO;
+           }
+
+           /*
+              There are at least two accepting states left.  Presumably
+              the number of accepting states is going to be low,
+              typically two. So we simply scan through to find the one
+              with lowest wordnum.  Once we find it, we swap the last
+              state into its place and decrement the size. We then try to
+              match the rest of the pattern at the point where the word
+              ends. If we succeed, control just continues along the
+              regex; if we fail we return here to try the next accepting
+              state
+            */
+
+           {
+               U32 best = 0;
+               U32 cur;
+               for( cur = 1 ; cur <= ST.accepted ; cur++ ) {
+                   DEBUG_TRIE_EXECUTE_r(
+                       PerlIO_printf( Perl_debug_log,
+                           "%*s  %sgot %"IVdf" (%d) as best, looking at %"IVdf" (%d)%s\n",
+                           REPORT_CODE_OFF + depth * 2, "", PL_colors[4],
+                           (IV)best, ST.accept_buff[ best ].wordnum, (IV)cur,
+                           ST.accept_buff[ cur ].wordnum, PL_colors[5] );
+                   );
+
+                   if (ST.accept_buff[cur].wordnum <
+                           ST.accept_buff[best].wordnum)
+                       best = cur;
                }
+
+               DEBUG_EXECUTE_r({
+                   reg_trie_data * const trie
+                       = (reg_trie_data*)rex->data->data[ ARG(ST.me) ];
+                   SV ** const tmp = RX_DEBUG(reginfo->prog)
+                               ? av_fetch( trie->words, ST.accept_buff[ best ].wordnum - 1, 0 )
+                               : NULL;
+                   regnode *nextop=!ST.jump ? 
+                                   ST.B : 
+                                   ST.B - ST.jump[ST.accept_buff[best].wordnum];    
+                   PerlIO_printf( Perl_debug_log, 
+                       "%*s  %strying alternation #%d <%s> at node #%d %s\n",
+                       REPORT_CODE_OFF+depth*2, "", PL_colors[4],
+                       ST.accept_buff[best].wordnum,
+                       tmp ? SvPV_nolen_const( *tmp ) : "not compiled under -Dr", 
+                           REG_NODE_NUM(nextop),
+                       PL_colors[5] );
+               });
+
+               if ( best<ST.accepted ) {
+                   reg_trie_accepted tmp = ST.accept_buff[ best ];
+                   ST.accept_buff[ best ] = ST.accept_buff[ ST.accepted ];
+                   ST.accept_buff[ ST.accepted ] = tmp;
+                   best = ST.accepted;
+               }
+               PL_reginput = (char *)ST.accept_buff[ best ].endpos;
+               if ( !ST.jump ) {
+                   PUSH_STATE_GOTO(TRIE_next, ST.B);
+                   /* NOTREACHED */
+               } else {
+                   PUSH_STATE_GOTO(TRIE_next, ST.B - ST.jump[ST.accept_buff[best].wordnum]);
+                   /* NOTREACHED */
+                }
+                /* NOTREACHED */
            }
-           /* unreached codepoint */
+           /* NOTREACHED */
+
+#undef  ST
+
        case EXACT: {
            char *s = STRING(scan);
            ln = STR_LEN(scan);
            if (do_utf8 != UTF) {
                /* The target and the pattern have differing utf8ness. */
                char *l = locinput;
-               const char *e = s + ln;
+               const char * const e = s + ln;
 
                if (do_utf8) {
                    /* The target is utf8, the pattern is not utf8. */
@@ -2966,12 +3031,12 @@ S_regmatch(pTHX_ regnode *prog)
            PL_reg_flags |= RF_tainted;
            /* FALL THROUGH */
        case EXACTF: {
-           char *s = STRING(scan);
+           char * const s = STRING(scan);
            ln = STR_LEN(scan);
 
            if (do_utf8 || UTF) {
              /* Either target or the pattern are utf8. */
-               char *l = locinput;
+               const char * const l = locinput;
                char *e = PL_regeol;
 
                if (ibcmp_utf8(s, 0,  ln, (bool)UTF,
@@ -3015,8 +3080,8 @@ S_regmatch(pTHX_ regnode *prog)
            if (do_utf8) {
                STRLEN inclasslen = PL_regeol - locinput;
 
-               if (!reginclass(scan, (U8*)locinput, &inclasslen, do_utf8))
-                   sayNO_ANYOF;
+               if (!reginclass(rex, scan, (U8*)locinput, &inclasslen, do_utf8))
+                   goto anyof_fail;
                if (locinput >= PL_regeol)
                    sayNO;
                locinput += inclasslen ? inclasslen : UTF8SKIP(locinput);
@@ -3026,14 +3091,14 @@ S_regmatch(pTHX_ regnode *prog)
            else {
                if (nextchr < 0)
                    nextchr = UCHARAT(locinput);
-               if (!REGINCLASS(scan, (U8*)locinput))
-                   sayNO_ANYOF;
+               if (!REGINCLASS(rex, scan, (U8*)locinput))
+                   goto anyof_fail;
                if (!nextchr && locinput >= PL_regeol)
                    sayNO;
                nextchr = UCHARAT(++locinput);
                break;
            }
-       no_anyof:
+       anyof_fail:
            /* If we might have the case of the German sharp s
             * in a casefolding Unicode character class. */
 
@@ -3053,7 +3118,7 @@ S_regmatch(pTHX_ regnode *prog)
            if (do_utf8) {
                LOAD_UTF8_CHARCLASS_ALNUM();
                if (!(OP(scan) == ALNUM
-                     ? swash_fetch(PL_utf8_alnum, (U8*)locinput, do_utf8)
+                     ? (bool)swash_fetch(PL_utf8_alnum, (U8*)locinput, do_utf8)
                      : isALNUM_LC_utf8((U8*)locinput)))
                {
                    sayNO;
@@ -3076,7 +3141,7 @@ S_regmatch(pTHX_ regnode *prog)
            if (do_utf8) {
                LOAD_UTF8_CHARCLASS_ALNUM();
                if (OP(scan) == NALNUM
-                   ? swash_fetch(PL_utf8_alnum, (U8*)locinput, do_utf8)
+                   ? (bool)swash_fetch(PL_utf8_alnum, (U8*)locinput, do_utf8)
                    : isALNUM_LC_utf8((U8*)locinput))
                {
                    sayNO;
@@ -3103,7 +3168,7 @@ S_regmatch(pTHX_ regnode *prog)
                else {
                    const U8 * const r = reghop3((U8*)locinput, -1, (U8*)PL_bostr);
                
-                   ln = utf8n_to_uvchr(r, UTF8SKIP(r), 0, 0);
+                   ln = utf8n_to_uvchr(r, UTF8SKIP(r), 0, uniflags);
                }
                if (OP(scan) == BOUND || OP(scan) == NBOUND) {
                    ln = isALNUM_uni(ln);
@@ -3141,7 +3206,7 @@ S_regmatch(pTHX_ regnode *prog)
                if (UTF8_IS_CONTINUED(nextchr)) {
                    LOAD_UTF8_CHARCLASS_SPACE();
                    if (!(OP(scan) == SPACE
-                         ? swash_fetch(PL_utf8_space, (U8*)locinput, do_utf8)
+                         ? (bool)swash_fetch(PL_utf8_space, (U8*)locinput, do_utf8)
                          : isSPACE_LC_utf8((U8*)locinput)))
                    {
                        sayNO;
@@ -3171,7 +3236,7 @@ S_regmatch(pTHX_ regnode *prog)
            if (do_utf8) {
                LOAD_UTF8_CHARCLASS_SPACE();
                if (OP(scan) == NSPACE
-                   ? swash_fetch(PL_utf8_space, (U8*)locinput, do_utf8)
+                   ? (bool)swash_fetch(PL_utf8_space, (U8*)locinput, do_utf8)
                    : isSPACE_LC_utf8((U8*)locinput))
                {
                    sayNO;
@@ -3194,7 +3259,7 @@ S_regmatch(pTHX_ regnode *prog)
            if (do_utf8) {
                LOAD_UTF8_CHARCLASS_DIGIT();
                if (!(OP(scan) == DIGIT
-                     ? swash_fetch(PL_utf8_digit, (U8*)locinput, do_utf8)
+                     ? (bool)swash_fetch(PL_utf8_digit, (U8*)locinput, do_utf8)
                      : isDIGIT_LC_utf8((U8*)locinput)))
                {
                    sayNO;
@@ -3217,7 +3282,7 @@ S_regmatch(pTHX_ regnode *prog)
            if (do_utf8) {
                LOAD_UTF8_CHARCLASS_DIGIT();
                if (OP(scan) == NDIGIT
-                   ? swash_fetch(PL_utf8_digit, (U8*)locinput, do_utf8)
+                   ? (bool)swash_fetch(PL_utf8_digit, (U8*)locinput, do_utf8)
                    : isDIGIT_LC_utf8((U8*)locinput))
                {
                    sayNO;
@@ -3249,13 +3314,33 @@ S_regmatch(pTHX_ regnode *prog)
               locinput++;
            nextchr = UCHARAT(locinput);
            break;
+            
+       case NREFFL:
+       {
+           char *s;
+           char type;
+           PL_reg_flags |= RF_tainted;
+           /* FALL THROUGH */
+       case NREF:
+       case NREFF:
+           type = OP(scan);
+           n = reg_check_named_buff_matched(rex,scan);
+
+            if ( n ) {
+                type = REF + ( type - NREF );
+                goto do_ref;
+            } else {
+                sayNO;
+            }
+            /* unreached */
        case REFFL:
            PL_reg_flags |= RF_tainted;
            /* FALL THROUGH */
         case REF:
-       case REFF: {
-           char *s;
+       case REFF: 
            n = ARG(scan);  /* which paren pair */
+           type = OP(scan);
+         do_ref:  
            ln = PL_regstartp[n];
            PL_reg_leftiter = PL_reg_maxiter;           /* Void cache */
            if ((I32)*PL_reglastparen < n || ln == -1)
@@ -3264,7 +3349,7 @@ S_regmatch(pTHX_ regnode *prog)
                break;
 
            s = PL_bostr + ln;
-           if (do_utf8 && OP(scan) != REF) {   /* REF can do byte comparison */
+           if (do_utf8 && type != REF) {       /* REF can do byte comparison */
                char *l = locinput;
                const char *e = PL_bostr + PL_regendp[n];
                /*
@@ -3272,7 +3357,7 @@ S_regmatch(pTHX_ regnode *prog)
                 * in the 8-bit case (no pun intended) because in Unicode we
                 * have to map both upper and title case to lower case.
                 */
-               if (OP(scan) == REFF) {
+               if (type == REFF) {
                    while (s < e) {
                        STRLEN ulen1, ulen2;
                        U8 tmpbuf1[UTF8_MAXBYTES_CASE+1];
@@ -3295,46 +3380,78 @@ S_regmatch(pTHX_ regnode *prog)
 
            /* Inline the first character, for speed. */
            if (UCHARAT(s) != nextchr &&
-               (OP(scan) == REF ||
-                (UCHARAT(s) != ((OP(scan) == REFF
-                                 ? PL_fold : PL_fold_locale)[nextchr]))))
+               (type == REF ||
+                (UCHARAT(s) != (type == REFF
+                                 ? PL_fold : PL_fold_locale)[nextchr])))
                sayNO;
            ln = PL_regendp[n] - ln;
            if (locinput + ln > PL_regeol)
                sayNO;
-           if (ln > 1 && (OP(scan) == REF
+           if (ln > 1 && (type == REF
                           ? memNE(s, locinput, ln)
-                          : (OP(scan) == REFF
+                          : (type == REFF
                              ? ibcmp(s, locinput, ln)
                              : ibcmp_locale(s, locinput, ln))))
                sayNO;
            locinput += ln;
            nextchr = UCHARAT(locinput);
            break;
-           }
-
+       }
        case NOTHING:
        case TAIL:
            break;
        case BACK:
            break;
-       case EVAL:
+
+#undef  ST
+#define ST st->u.eval
        {
-           dSP;
-           OP_4tree * const oop = PL_op;
-           COP * const ocurcop = PL_curcop;
-           PAD *old_comppad;
            SV *ret;
-           struct regexp * const oreg = PL_reg_re;
-       
-           n = ARG(scan);
-           PL_op = (OP_4tree*)PL_regdata->data[n];
-           DEBUG_EXECUTE_r( PerlIO_printf(Perl_debug_log, "  re_eval 0x%"UVxf"\n", PTR2UV(PL_op)) );
-           PAD_SAVE_LOCAL(old_comppad, (PAD*)PL_regdata->data[n + 2]);
-           PL_regendp[0] = PL_reg_magic->mg_len = locinput - PL_bostr;
-
+            regexp *re;
+            regnode *startpoint;           
+            
+        case SRECURSE:
+       case RECURSE: /*    /(...(?1))/      */
+            if (cur_eval && cur_eval->locinput==locinput) {
+                if (cur_eval->u.eval.close_paren == ARG(scan)) 
+                    Perl_croak(aTHX_ "Infinite recursion in RECURSE in regexp");
+                if ( ++nochange_depth > MAX_RECURSE_EVAL_NOCHANGE_DEPTH ) 
+                    Perl_croak(aTHX_ "RECURSE without pos change exceeded limit in regexp");
+            } else {
+                nochange_depth = 0;
+            }    
+            re = rex;
+            (void)ReREFCNT_inc(rex);
+            if (OP(scan)==RECURSE) {
+                startpoint = scan + ARG2L(scan);
+                ST.close_paren = ARG(scan);
+            } else {
+                startpoint = re->program+1;
+                ST.close_paren = 0;
+            }
+            goto eval_recurse_doit;
+            /* NOTREACHED */
+        case EVAL:  /*   /(?{A})B/   /(??{A})B/  and /(?(?{A})X|Y)B/   */        
+            if (cur_eval && cur_eval->locinput==locinput) {
+                if ( ++nochange_depth > MAX_RECURSE_EVAL_NOCHANGE_DEPTH ) 
+                    Perl_croak(aTHX_ "EVAL without pos change exceeded limit in regexp");
+            } else {
+                nochange_depth = 0;
+            }    
            {
+               /* execute the code in the {...} */
+               dSP;
                SV ** const before = SP;
+               OP_4tree * const oop = PL_op;
+               COP * const ocurcop = PL_curcop;
+               PAD *old_comppad;
+           
+               n = ARG(scan);
+               PL_op = (OP_4tree*)rex->data->data[n];
+               DEBUG_EXECUTE_r( PerlIO_printf(Perl_debug_log, "  re_eval 0x%"UVxf"\n", PTR2UV(PL_op)) );
+               PAD_SAVE_LOCAL(old_comppad, (PAD*)rex->data->data[n + 2]);
+               PL_regendp[0] = PL_reg_magic->mg_len = locinput - PL_bostr;
+
                CALLRUNOPS(aTHX);                       /* Scalar context. */
                SPAGAIN;
                if (SP == before)
@@ -3343,19 +3460,24 @@ S_regmatch(pTHX_ regnode *prog)
                    ret = POPs;
                    PUTBACK;
                }
+
+               PL_op = oop;
+               PAD_RESTORE_LOCAL(old_comppad);
+               PL_curcop = ocurcop;
+               if (!logical) {
+                   /* /(?{...})/ */
+                   sv_setsv(save_scalar(PL_replgv), ret);
+                   break;
+               }
            }
+           if (logical == 2) { /* Postponed subexpression: /(??{...})/ */
+               logical = 0;
+               {
+                   /* extract RE object from returned value; compiling if
+                    * necessary */
 
-           PL_op = oop;
-           PAD_RESTORE_LOCAL(old_comppad);
-           PL_curcop = ocurcop;
-           if (logical) {
-               if (logical == 2) {     /* Postponed subexpression. */
-                   regexp *re;
                    MAGIC *mg = NULL;
-                   re_cc_state state;
-                    int toggleutf;
-                   register SV *sv;
-
+                   const SV *sv;
                    if(SvROK(ret) && SvSMAGICAL(sv = SvRV(ret)))
                        mg = mg_find(sv, PERL_MAGIC_qr);
                    else if (SvSMAGICAL(ret)) {
@@ -3373,97 +3495,102 @@ S_regmatch(pTHX_ regnode *prog)
                        STRLEN len;
                        const char * const t = SvPV_const(ret, len);
                        PMOP pm;
-                       char * const oprecomp = PL_regprecomp;
                        const I32 osize = PL_regsize;
-                       const I32 onpar = PL_regnpar;
 
                        Zero(&pm, 1, PMOP);
-                        if (DO_UTF8(ret)) pm.op_pmdynflags |= PMdf_DYN_UTF8;
-                       re = CALLREGCOMP(aTHX_ (char*)t, (char*)t + len, &pm);
+                       if (DO_UTF8(ret)) pm.op_pmdynflags |= PMdf_DYN_UTF8;
+                       re = CALLREGCOMP((char*)t, (char*)t + len, &pm);
                        if (!(SvFLAGS(ret)
                              & (SVs_TEMP | SVs_PADTMP | SVf_READONLY
                                | SVs_GMG)))
                            sv_magic(ret,(SV*)ReREFCNT_inc(re),
                                        PERL_MAGIC_qr,0,0);
-                       PL_regprecomp = oprecomp;
                        PL_regsize = osize;
-                       PL_regnpar = onpar;
                    }
-                   DEBUG_EXECUTE_r(
-                       PerlIO_printf(Perl_debug_log,
-                                     "Entering embedded \"%s%.60s%s%s\"\n",
-                                     PL_colors[0],
-                                     re->precomp,
-                                     PL_colors[1],
-                                     (strlen(re->precomp) > 60 ? "..." : ""))
-                       );
-                   state.node = next;
-                   state.prev = PL_reg_call_cc;
-                   state.cc = cc;
-                   state.re = PL_reg_re;
-
-                   cc = 0;
-               
-                   cp = regcppush(0);  /* Save *all* the positions. */
-                   REGCP_SET(lastcp);
-                   cache_re(re);
-                   state.ss = PL_savestack_ix;
-                   *PL_reglastparen = 0;
-                   *PL_reglastcloseparen = 0;
-                   PL_reg_call_cc = &state;
-                   PL_reginput = locinput;
-                   toggleutf = ((PL_reg_flags & RF_utf8) != 0) ^
-                               ((re->reganch & ROPT_UTF8) != 0);
-                   if (toggleutf) PL_reg_flags ^= RF_utf8;
-
-                   /* XXXX This is too dramatic a measure... */
-                   PL_reg_maxiter = 0;
-
-                   /* XXX the only recursion left in regmatch() */
-                   if (regmatch(re->program + 1)) {
-                       /* Even though we succeeded, we need to restore
-                          global variables, since we may be wrapped inside
-                          SUSPEND, thus the match may be not finished yet. */
-
-                       /* XXXX Do this only if SUSPENDed? */
-                       PL_reg_call_cc = state.prev;
-                       cc = state.cc;
-                       PL_reg_re = state.re;
-                       cache_re(PL_reg_re);
-                       if (toggleutf) PL_reg_flags ^= RF_utf8;
-
-                       /* XXXX This is too dramatic a measure... */
-                       PL_reg_maxiter = 0;
-
-                       /* These are needed even if not SUSPEND. */
-                       ReREFCNT_dec(re);
-                       regcpblow(cp);
-                       sayYES;
-                   }
-                   ReREFCNT_dec(re);
-                   REGCP_UNWIND(lastcp);
-                   regcppop();
-                   PL_reg_call_cc = state.prev;
-                   cc = state.cc;
-                   PL_reg_re = state.re;
-                   cache_re(PL_reg_re);
-                   if (toggleutf) PL_reg_flags ^= RF_utf8;
-
-                   /* XXXX This is too dramatic a measure... */
-                   PL_reg_maxiter = 0;
-
-                   logical = 0;
-                   sayNO;
                }
-               sw = SvTRUE(ret);
-               logical = 0;
-           }
-           else {
-               sv_setsv(save_scalar(PL_replgv), ret);
-               cache_re(oreg);
+                DEBUG_EXECUTE_r(
+                    debug_start_match(re, do_utf8, locinput, PL_regeol, 
+                        "Matching embedded");
+               );              
+               startpoint = re->program + 1;
+                       ST.close_paren = 0; /* only used for RECURSE */
+                       /* borrowed from regtry */
+                if (PL_reg_start_tmpl <= re->nparens) {
+                    PL_reg_start_tmpl = re->nparens*3/2 + 3;
+                    if(PL_reg_start_tmp)
+                        Renew(PL_reg_start_tmp, PL_reg_start_tmpl, char*);
+                    else
+                        Newx(PL_reg_start_tmp, PL_reg_start_tmpl, char*);
+                }                      
+
+        eval_recurse_doit: /* Share code with RECURSE below this line */
+               /* run the pattern returned from (??{...}) */
+               ST.cp = regcppush(0);   /* Save *all* the positions. */
+               REGCP_SET(ST.lastcp);
+               
+               PL_regstartp = re->startp; /* essentially NOOP on RECURSE */
+               PL_regendp = re->endp;     /* essentially NOOP on RECURSE */
+               
+               *PL_reglastparen = 0;
+               *PL_reglastcloseparen = 0;
+               PL_reginput = locinput;
+               PL_regsize = 0;
+
+               /* XXXX This is too dramatic a measure... */
+               PL_reg_maxiter = 0;
+
+               ST.toggle_reg_flags = PL_reg_flags;
+               if (re->reganch & ROPT_UTF8)
+                   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;
+               ST.prev_curlyx = cur_curlyx;
+               rex = re;
+               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);
+               /* NOTREACHED */
            }
+           /* logical is 1,   /(?(?{...})X|Y)/ */
+           sw = (bool)SvTRUE(ret);
+           logical = 0;
            break;
        }
+
+       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; 
+           ReREFCNT_dec(rex);
+           rex = ST.prev_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;
+           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; 
+           ReREFCNT_dec(rex);
+           rex = ST.prev_rex;
+           PL_reginput = locinput;
+           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;
+           sayNO_SILENT;
+#undef ST
+
        case OPEN:
            n = ARG(scan);  /* which paren pair */
            PL_reg_start_tmp[n] = locinput;
@@ -3477,11 +3604,25 @@ S_regmatch(pTHX_ regnode *prog)
            if (n > (I32)*PL_reglastparen)
                *PL_reglastparen = n;
            *PL_reglastcloseparen = n;
+            if (cur_eval && cur_eval->u.eval.close_paren == (U32)n) {
+               goto fake_end;
+           }    
            break;
        case GROUPP:
            n = ARG(scan);  /* which paren pair */
-           sw = ((I32)*PL_reglastparen >= n && PL_regendp[n] != -1);
+           sw = (bool)((I32)*PL_reglastparen >= n && PL_regendp[n] != -1);
+           break;
+       case NGROUPP:
+           /* reg_check_named_buff_matched returns 0 for no match */
+           sw = (bool)(0 < reg_check_named_buff_matched(rex,scan));
            break;
+        case RECURSEP:
+            n = ARG(scan);
+            sw = (cur_eval && (!n || cur_eval->u.eval.close_paren == n));
+            break;
+        case DEFINEP:
+            sw = 0;
+            break;
        case IFTHEN:
            PL_reg_leftiter = PL_reg_maxiter;           /* Void cache */
            if (sw)
@@ -3495,188 +3636,197 @@ S_regmatch(pTHX_ regnode *prog)
        case LOGICAL:
            logical = scan->flags;
            break;
+
 /*******************************************************************
- cc contains infoblock about the innermost (...)* loop, and
- a pointer to the next outer infoblock.
 
- Here is how Y(A)*Z is processed (if it is compiled into CURLYX/WHILEM):
+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.)
 
-   1) After matching Y, regnode for CURLYX is processed;
+A*B is compiled as <CURLYX><A><WHILEM><B>
 
-   2) This regnode mallocs an infoblock, and calls regmatch() recursively
-      with the starting point at WHILEM node;
+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.
 
-   3) Each hit of WHILEM node tries to match A and Z (in the order
-      depending on the current iteration, min/max of {min,max} and
-      greediness).  The information about where are nodes for "A"
-      and "Z" is read from the infoblock, as is info on how many times "A"
-      was already matched, and greediness.
+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).
 
-   4) After A matches, the same WHILEM node is hit again.
+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.
 
-   5) Each time WHILEM is hit, cc is the infoblock created by CURLYX
-      of the same pair.  Thus when WHILEM tries to match Z, it temporarily
-      resets cc, since this Y(A)*Z can be a part of some other loop:
-      as in (Y(A)*Z)*.  If Z matches, the automaton will hit the WHILEM node
-      of the external loop.
+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):
 
- Currently present infoblocks form a tree with a stem formed by PL_curcc
- and whatever it mentions via ->next, and additional attached trees
- corresponding to temporarily unset infoblocks as in "5" above.
+    <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
 
- In the following picture, infoblocks for outer loop of
- (Y(A)*?Z)*?T are denoted O, for inner I.  NULL starting block
- is denoted by x.  The matched string is YAAZYAZT.  Temporarily postponed
- infoblocks are drawn below the "reset" infoblock.
+(Contrast this with something like CURLYM, which maintains only a single
+backtrack state:
 
- In fact in the picture below we do not show failed matches for Z and T
- by WHILEM blocks.  [We illustrate minimal matches, since for them it is
- more obvious *why* one needs to *temporary* unset infoblocks.]
+    <CURLYM cnt=0> a1
+    a1 <CURLYM cnt=1> a2
+    a1 a2 <CURLYM cnt=2> a3
+    a1 a2 a3 <CURLYM cnt=3> b
+)
 
-  Matched      REx position    InfoBlocks      Comment
-               (Y(A)*?Z)*?T    x
-               Y(A)*?Z)*?T     x <- O
-  Y            (A)*?Z)*?T      x <- O
-  Y            A)*?Z)*?T       x <- O <- I
-  YA           )*?Z)*?T        x <- O <- I
-  YA           A)*?Z)*?T       x <- O <- I
-  YAA          )*?Z)*?T        x <- O <- I
-  YAA          Z)*?T           x <- O          # Temporary unset I
-                                    I
+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.
 
-  YAAZ         Y(A)*?Z)*?T     x <- O
-                                    I
+This is complicated slightly by nested CURLYX/WHILEM's. Since cur_curlyx
+must always point to the *current* CURLYX block, the rules are:
 
-  YAAZY                (A)*?Z)*?T      x <- O
-                                    I
+When executing CURLYX, save the old cur_curlyx in the CURLYX state block,
+and set cur_curlyx to point the new block.
 
-  YAAZY                A)*?Z)*?T       x <- O <- I
-                                    I
+When popping the CURLYX block after a successful or unsuccessful match,
+restore the previous cur_curlyx.
 
-  YAAZYA       )*?Z)*?T        x <- O <- I     
-                                    I
+When WHILEM is about to execute B, save the current cur_curlyx, and set it
+to the outer one saved in the CURLYX block.
 
-  YAAZYA       Z)*?T           x <- O          # Temporary unset I
-                                    I,I
+When popping the WHILEM block after a successful or unsuccessful B match,
+restore the previous cur_curlyx.
 
-  YAAZYAZ      )*?T            x <- O
-                                    I,I
+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:
 
-  YAAZYAZ      T               x               # Temporary unset O
-                               O
-                               I,I
+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
 
-  YAAZYAZT                     x
-                               O
-                               I,I
- *******************************************************************/
+At this point the pattern succeeds, and we work back down the stack to
+clean up, restoring as we go:
 
-       case CURLYX: {
-               /* No need to save/restore up to this paren */
-               I32 parenfloor = scan->flags;
+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   
 
-               {
-                   CURCUR *newcc;
-                   Newx(newcc, 1, CURCUR);
-                   oldcc = cc;
-                   newcc->oldcc = cc;
-                   cc = newcc;
-               }
-               cp = PL_savestack_ix;
-               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)*PL_reglastparen)
-                   parenfloor = *PL_reglastparen; /* Pessimization... */
-               cc->parenfloor = parenfloor;
-               cc->cur = -1;
-               cc->min = ARG1(scan);
-               cc->max  = ARG2(scan);
-               cc->scan = NEXTOPER(scan) + EXTRA_STEP_2ARGS;
-               cc->next = next;
-               cc->minmod = minmod;
-               cc->lastloc = 0;
-               PL_reginput = locinput;
-               REGMATCH(PREVOPER(next), CURLYX); /* start on the WHILEM */
-               /*** all unsaved local vars undefined at this point */
-               regcpblow(cp);
-               Safefree(cc);
-               cc = oldcc;
-               saySAME(result);
-           }
+*******************************************************************/
+
+#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)*PL_reglastparen)
+               parenfloor = *PL_reglastparen; /* 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.min = ARG1(scan);
+           ST.max = ARG2(scan);
+           ST.A = NEXTOPER(scan) + EXTRA_STEP_2ARGS;
+           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 */
+
+           PL_reginput = locinput;
+           PUSH_YES_STATE_GOTO(CURLYX_end, PREVOPER(next));
            /* NOTREACHED */
-       case WHILEM: {
-               /*
-                * This is really hard to understand, because after we match
-                * what we're trying to match, we must make sure the rest of
-                * the REx is going to match for sure, and to do that we have
-                * to go back UP the parse tree by recursing ever deeper.  And
-                * if it fails, we have to reset our parent's current state
-                * that we can try again after backing off.
-                */
+       }
 
-               lastloc = cc->lastloc; /* Detection of 0-len. */
-               cache_offset = 0;
-               cache_bit = 0;
-               
-               n = cc->cur + 1;        /* how many we know we matched */
-               PL_reginput = locinput;
+       case CURLYX_end: /* just finished matching all of A*B */
+           regcpblow(ST.cp);
+           cur_curlyx = ST.prev_curlyx;
+           sayYES;
+           /* NOTREACHED */
 
-               DEBUG_EXECUTE_r(
-                   PerlIO_printf(Perl_debug_log,
-                                 "%*s  %ld out of %ld..%ld  cc=%"UVxf"\n",
-                                 REPORT_CODE_OFF+PL_regindent*2, "",
-                                 (long)n, (long)cc->min,
-                                 (long)cc->max, PTR2UV(cc))
-                   );
+       case CURLYX_end_fail: /* just failed to match all of A*B */
+           regcpblow(ST.cp);
+           cur_curlyx = ST.prev_curlyx;
+           sayNO;
+           /* NOTREACHED */
 
-               /* If degenerate scan matches "", assume scan done. */
-
-               if (locinput == cc->lastloc && n >= cc->min) {
-                   oldcc = cc;
-                   cc = cc->oldcc;
-                   if (cc)
-                       ln = cc->cur;
-                   DEBUG_EXECUTE_r(
-                       PerlIO_printf(Perl_debug_log,
-                          "%*s  empty match detected, try continuation...\n",
-                          REPORT_CODE_OFF+PL_regindent*2, "")
-                       );
-                   REGMATCH(oldcc->next, WHILEM1);
-                   /*** all unsaved local vars undefined at this point */
-                   cc = oldcc;
-                   if (result)
-                       sayYES;
-                   if (cc->oldcc)
-                       cc->oldcc->cur = ln;
-                   sayNO;
-               }
 
-               /* First just match a string of min scans. */
-
-               if (n < cc->min) {
-                   cc->cur = n;
-                   cc->lastloc = locinput;
-                   REGMATCH(cc->scan, WHILEM2);
-                   /*** all unsaved local vars undefined at this point */
-                   if (result)
-                       sayYES;
-                   cc->cur = n - 1;
-                   cc->lastloc = lastloc;
-                   sayNO;
-               }
+#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;
+           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;
+           
+           PL_reginput = locinput;
+
+           DEBUG_EXECUTE_r( PerlIO_printf(Perl_debug_log,
+                 "%*s  whilem: matched %ld out of %ld..%ld\n",
+                 REPORT_CODE_OFF+depth*2, "", (long)n,
+                 (long)cur_curlyx->u.curlyx.min,
+                 (long)cur_curlyx->u.curlyx.max)
+           );
+
+           /* First just match a string of min A's. */
+
+           if (n < cur_curlyx->u.curlyx.min) {
+               cur_curlyx->u.curlyx.lastloc = locinput;
+               PUSH_STATE_GOTO(WHILEM_A_pre, cur_curlyx->u.curlyx.A);
+               /* 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 (scan->flags) {
-                   /* Check whether we already were at this position.
-                       Postpone detection until we know the match is not
-                       *that* much linear. */
                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) {
-                   const I32 size = (PL_reg_maxiter + 7 + POSCACHE_START)/8;
+                   /* 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);
@@ -3688,422 +3838,419 @@ S_regmatch(pTHX_ regnode *prog)
                        PL_reg_poscache_size = size;
                        Newxz(PL_reg_poscache, size, char);
                    }
-                   DEBUG_EXECUTE_r(
-                       PerlIO_printf(Perl_debug_log,
-             "%sDetected a super-linear match, switching on caching%s...\n",
-                                     PL_colors[4], PL_colors[5])
-                       );
+                   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) {
-                   cache_offset = locinput - PL_bostr;
-
-                   cache_offset = (scan->flags & 0xf) - 1 + POSCACHE_START
-                           + cache_offset * (scan->flags>>4);
-                   cache_bit = cache_offset % 8;
-                   cache_offset /= 8;
-                   if (PL_reg_poscache[cache_offset] & (1<<cache_bit)) {
-                   DEBUG_EXECUTE_r(
-                       PerlIO_printf(Perl_debug_log,
-                                     "%*s  already tried at this position...\n",
-                                     REPORT_CODE_OFF+PL_regindent*2, "")
+                   /* 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, "")
                        );
-                       if (PL_reg_poscache[0] & (1<<POSCACHE_SUCCESS))
-                           /* cache records success */
-                           sayYES;
-                       else
-                           /* cache records failure */
-                           sayNO_SILENT;
+                       sayNO; /* cache records failure */
                    }
-                   PL_reg_poscache[cache_offset] |= (1<<cache_bit);
-               }
+                   ST.cache_offset = offset;
+                   ST.cache_mask   = mask;
                }
+           }
 
-               /* Prefer next over scan for minimal matching. */
-
-               if (cc->minmod) {
-                   oldcc = cc;
-                   cc = cc->oldcc;
-                   if (cc)
-                       ln = cc->cur;
-                   cp = regcppush(oldcc->parenfloor);
-                   REGCP_SET(lastcp);
-                   REGMATCH(oldcc->next, WHILEM3);
-                   /*** all unsaved local vars undefined at this point */
-                   cc = oldcc;
-                   if (result) {
-                       regcpblow(cp);
-                       CACHEsayYES;    /* All done. */
-                   }
-                   REGCP_UNWIND(lastcp);
-                   regcppop();
-                   if (cc->oldcc)
-                       cc->oldcc->cur = ln;
-
-                   if (n >= cc->max) { /* Maximum greed exceeded? */
-                       if (ckWARN(WARN_REGEXP) && n >= REG_INFTY
-                           && !(PL_reg_flags & RF_warned)) {
-                           PL_reg_flags |= RF_warned;
-                           Perl_warner(aTHX_ packWARN(WARN_REGEXP), "%s limit (%d) exceeded",
-                                "Complex regular subexpression recursion",
-                                REG_INFTY - 1);
-                       }
-                       CACHEsayNO;
-                   }
+           /* Prefer B over A for minimal matching. */
 
-                   DEBUG_EXECUTE_r(
-                       PerlIO_printf(Perl_debug_log,
-                                     "%*s  trying longer...\n",
-                                     REPORT_CODE_OFF+PL_regindent*2, "")
-                       );
-                   /* Try scanning more and see if it helps. */
-                   PL_reginput = locinput;
-                   cc->cur = n;
-                   cc->lastloc = locinput;
-                   cp = regcppush(cc->parenfloor);
-                   REGCP_SET(lastcp);
-                   REGMATCH(cc->scan, WHILEM4);
-                   /*** all unsaved local vars undefined at this point */
-                   if (result) {
-                       regcpblow(cp);
-                       CACHEsayYES;
-                   }
-                   REGCP_UNWIND(lastcp);
-                   regcppop();
-                   cc->cur = n - 1;
-                   cc->lastloc = lastloc;
-                   CACHEsayNO;
-               }
+           if (cur_curlyx->u.curlyx.minmod) {
+               ST.save_curlyx = cur_curlyx;
+               cur_curlyx = cur_curlyx->u.curlyx.prev_curlyx;
+               ST.cp = regcppush(ST.save_curlyx->u.curlyx.parenfloor);
+               REGCP_SET(ST.lastcp);
+               PUSH_YES_STATE_GOTO(WHILEM_B_min, ST.save_curlyx->u.curlyx.B);
+               /* NOTREACHED */
+           }
 
-               /* Prefer scan over next for maximal matching. */
-
-               if (n < cc->max) {      /* More greed allowed? */
-                   cp = regcppush(cc->parenfloor);
-                   cc->cur = n;
-                   cc->lastloc = locinput;
-                   REGCP_SET(lastcp);
-                   REGMATCH(cc->scan, WHILEM5);
-                   /*** all unsaved local vars undefined at this point */
-                   if (result) {
-                       regcpblow(cp);
-                       CACHEsayYES;
-                   }
-                   REGCP_UNWIND(lastcp);
-                   regcppop();         /* Restore some previous $<digit>s? */
-                   PL_reginput = locinput;
-                   DEBUG_EXECUTE_r(
-                       PerlIO_printf(Perl_debug_log,
-                                     "%*s  failed, try continuation...\n",
-                                     REPORT_CODE_OFF+PL_regindent*2, "")
-                       );
-               }
-               if (ckWARN(WARN_REGEXP) && n >= REG_INFTY
-                       && !(PL_reg_flags & RF_warned)) {
+           /* Prefer A over B for maximal matching. */
+
+           if (n < cur_curlyx->u.curlyx.max) { /* More greed allowed? */
+               ST.cp = regcppush(cur_curlyx->u.curlyx.parenfloor);
+               cur_curlyx->u.curlyx.lastloc = locinput;
+               REGCP_SET(ST.lastcp);
+               PUSH_STATE_GOTO(WHILEM_A_max, cur_curlyx->u.curlyx.A);
+               /* NOTREACHED */
+           }
+           goto do_whilem_B_max;
+       }
+       /* 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;
+           /* 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;
+           /* NOTREACHED */
+
+       case WHILEM_A_min_fail: /* just failed to match A in a minimal match */
+           REGCP_UNWIND(ST.lastcp);
+           regcppop(rex);
+           /* FALL THROUGH */
+       case WHILEM_A_pre_fail: /* just failed to match even minimal A */
+           cur_curlyx->u.curlyx.lastloc = ST.save_lastloc;
+           cur_curlyx->u.curlyx.count--;
+           CACHEsayNO;
+           /* 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? */
+           PL_reginput = locinput;
+           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), "%s limit (%d) exceeded",
+                    "Complex regular subexpression recursion",
+                    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);
+           /* 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 >= cur_curlyx->u.curlyx.max) {
+               /* 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), "%s limit (%d) exceeded",
-                        "Complex regular subexpression recursion",
-                        REG_INFTY - 1);
+                   Perl_warner(aTHX_ packWARN(WARN_REGEXP),
+                       "%s limit (%d) exceeded",
+                       "Complex regular subexpression recursion",
+                       REG_INFTY - 1);
                }
-
-               /* Failed deeper matches of scan, so see if this one works. */
-               oldcc = cc;
-               cc = cc->oldcc;
-               if (cc)
-                   ln = cc->cur;
-               REGMATCH(oldcc->next, WHILEM6);
-               /*** all unsaved local vars undefined at this point */
-               cc = oldcc;
-               if (result)
-                   CACHEsayYES;
-               if (cc->oldcc)
-                   cc->oldcc->cur = ln;
-               cc->cur = n - 1;
-               cc->lastloc = lastloc;
+               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. */
+           PL_reginput = locinput;
+           cur_curlyx->u.curlyx.lastloc = locinput;
+           ST.cp = regcppush(cur_curlyx->u.curlyx.parenfloor);
+           REGCP_SET(ST.lastcp);
+           PUSH_STATE_GOTO(WHILEM_A_min, ST.save_curlyx->u.curlyx.A);
            /* NOTREACHED */
-       case BRANCHJ:
+
+#undef  ST
+#define ST st->u.branch
+
+       case BRANCHJ:       /*  /(...|A|...)/ with long next pointer */
            next = scan + ARG(scan);
            if (next == scan)
                next = NULL;
-           inner = NEXTOPER(NEXTOPER(scan));
-           goto do_branch;
-       case BRANCH:
-           inner = NEXTOPER(scan);
-         do_branch:
-           {
-               c1 = OP(scan);
-               if (OP(next) != c1)     /* No choice. */
-                   next = inner;       /* Avoid recursion. */
-               else {
-                   const I32 lastparen = *PL_reglastparen;
-                   /* Put unwinding data on stack */
-                   const I32 unwind1 = SSNEWt(1,re_unwind_branch_t);
-                   re_unwind_branch_t * const uw = SSPTRt(unwind1,re_unwind_branch_t);
-
-                   uw->prev = unwind;
-                   unwind = unwind1;
-                   uw->type = ((c1 == BRANCH)
-                               ? RE_UNWIND_BRANCH
-                               : RE_UNWIND_BRANCHJ);
-                   uw->lastparen = lastparen;
-                   uw->next = next;
-                   uw->locinput = locinput;
-                   uw->nextchr = nextchr;
-#ifdef DEBUGGING
-                   uw->regindent = ++PL_regindent;
-#endif
+           scan = NEXTOPER(scan);
+           /* FALL THROUGH */
 
-                   REGCP_SET(uw->lastcp);
+       case BRANCH:        /*  /(...|A|...)/ */
+           scan = NEXTOPER(scan); /* scan now points to inner node */
+           if (!next || (OP(next) != BRANCH && OP(next) != BRANCHJ))
+               /* last branch; skip state push and jump direct to node */
+               continue;
+           ST.lastparen = *PL_reglastparen;
+           ST.next_branch = next;
+           REGCP_SET(ST.cp);
+           PL_reginput = locinput;
 
-                   /* Now go into the first branch */
-                   next = inner;
-               }
-           }
-           break;
+           /* Now go into the branch */
+           PUSH_STATE_GOTO(BRANCH_next, scan);
+           /* NOTREACHED */
+
+       case BRANCH_next_fail: /* that branch failed; try the next, if any */
+           REGCP_UNWIND(ST.cp);
+           for (n = *PL_reglastparen; n > ST.lastparen; n--)
+               PL_regendp[n] = -1;
+           *PL_reglastparen = n;
+           /*dmq: *PL_reglastcloseparen = n; */
+           scan = ST.next_branch;
+           /* no more branches? */
+           if (!scan || (OP(scan) != BRANCH && OP(scan) != BRANCHJ))
+               sayNO;
+           continue; /* execute next BRANCH[J] op */
+           /* NOTREACHED */
+    
        case MINMOD:
            minmod = 1;
            break;
-       case CURLYM:
-       {
-           curlym_l = matches = 0;
-       
-           /* We suppose that the next guy does not need
-              backtracking: in particular, it is of constant non-zero length,
-              and has no parenths to influence future backrefs. */
-           ln = ARG1(scan);  /* min to match */
-           n  = ARG2(scan);  /* max to match */
-           paren = scan->flags;
-           if (paren) {
+
+#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 now 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;
+
+           /* if paren positive, emulate an OPEN/CLOSE around A */
+           if (ST.me->flags) {
+               I32 paren = ST.me->flags;
                if (paren > PL_regsize)
                    PL_regsize = paren;
                if (paren > (I32)*PL_reglastparen)
                    *PL_reglastparen = paren;
-           }
-           scan = NEXTOPER(scan) + NODE_STEP_REGNODE;
-           if (paren)
                scan += NEXT_OFF(scan); /* Skip former OPEN. */
-           PL_reginput = locinput;
-           maxwanted = minmod ? ln : n;
-           if (maxwanted) {
-               while (PL_reginput < PL_regeol && matches < maxwanted) {
-                   REGMATCH(scan, CURLYM1);
-                   /*** all unsaved local vars undefined at this point */
-                   if (!result)
-                       break;
-                   /* on first match, determine length, curlym_l */
-                   if (!matches++) {
-                       if (PL_reg_match_utf8) {
-                           char *s = locinput;
-                           while (s < PL_reginput) {
-                               curlym_l++;
-                               s += UTF8SKIP(s);
-                           }
-                       }
-                       else {
-                           curlym_l = PL_reginput - locinput;
-                       }
-                       if (curlym_l == 0) {
-                           matches = maxwanted;
-                           break;
-                       }
-                   }
-                   locinput = PL_reginput;
-               }
            }
+           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);
 
-           PL_reginput = locinput;
+           if (!(ST.minmod ? ARG1(ST.me) : ARG2(ST.me))) /* min/max */
+               goto curlym_do_B;
 
-           if (minmod) {
-               minmod = 0;
-               if (ln && matches < ln)
-                   sayNO;
-               if (HAS_TEXT(next) || JUMPABLE(next)) {
-                   regnode *text_node = next;
+         curlym_do_A: /* execute the A in /A{m,n}B/  */
+           PL_reginput = locinput;
+           PUSH_YES_STATE_GOTO(CURLYM_A, ST.A); /* match A */
+           /* NOTREACHED */
 
-                   if (! HAS_TEXT(text_node)) FIND_NEXT_IMPT(text_node);
+       case CURLYM_A: /* we've just matched an A */
+           locinput = st->locinput;
+           nextchr = UCHARAT(locinput);
 
-                   if (! HAS_TEXT(text_node)) c1 = c2 = -1000;
-                   else {
-                       if (PL_regkind[(U8)OP(text_node)] == REF) {
-                           c1 = c2 = -1000;
-                           goto assume_ok_MM;
-                       }
-                       else { c1 = (U8)*STRING(text_node); }
-                       if (OP(text_node) == EXACTF || OP(text_node) == REFF)
-                           c2 = PL_fold[c1];
-                       else if (OP(text_node) == EXACTFL || OP(text_node) == REFFL)
-                           c2 = PL_fold_locale[c1];
-                       else
-                           c2 = c1;
+           ST.count++;
+           /* after first match, determine A's length: u.curlym.alen */
+           if (ST.count == 1) {
+               if (PL_reg_match_utf8) {
+                   char *s = locinput;
+                   while (s < PL_reginput) {
+                       ST.alen++;
+                       s += UTF8SKIP(s);
                    }
                }
-               else
-                   c1 = c2 = -1000;
-           assume_ok_MM:
-               REGCP_SET(lastcp);
-               while (n >= ln || (n == REG_INFTY && ln > 0)) { /* ln overflow ? */
-                   /* If it could work, try it. */
-                   if (c1 == -1000 ||
-                       UCHARAT(PL_reginput) == c1 ||
-                       UCHARAT(PL_reginput) == c2)
-                   {
-                       if (paren) {
-                           if (ln) {
-                               PL_regstartp[paren] =
-                                   HOPc(PL_reginput, -curlym_l) - PL_bostr;
-                               PL_regendp[paren] = PL_reginput - PL_bostr;
-                           }
-                           else
-                               PL_regendp[paren] = -1;
-                       }
-                       REGMATCH(next, CURLYM2);
-                       /*** all unsaved local vars undefined at this point */
-                       if (result)
-                           sayYES;
-                       REGCP_UNWIND(lastcp);
-                   }
-                   /* Couldn't or didn't -- move forward. */
-                   PL_reginput = locinput;
-                   REGMATCH(scan, CURLYM3);
-                   /*** all unsaved local vars undefined at this point */
-                   if (result) {
-                       ln++;
-                       locinput = PL_reginput;
-                   }
-                   else
-                       sayNO;
+               else {
+                   ST.alen = PL_reginput - locinput;
                }
+               if (ST.alen == 0)
+                   ST.count = ST.minmod ? ARG1(ST.me) : ARG2(ST.me);
            }
-           else {
-               DEBUG_EXECUTE_r(
-                   PerlIO_printf(Perl_debug_log,
-                             "%*s  matched %"IVdf" times, len=%"IVdf"...\n",
-                             (int)(REPORT_CODE_OFF+PL_regindent*2), "",
-                             (IV) matches, (IV)curlym_l)
-                   );
-               if (matches >= ln) {
-                   if (HAS_TEXT(next) || JUMPABLE(next)) {
-                       regnode *text_node = next;
+           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 (! HAS_TEXT(text_node)) FIND_NEXT_IMPT(text_node);
+           locinput = PL_reginput;
+                       
+           if (cur_eval && cur_eval->u.eval.close_paren && 
+               cur_eval->u.eval.close_paren == ST.me->flags) 
+               goto fake_end;
+               
+           if ( ST.count < (ST.minmod ? ARG1(ST.me) : ARG2(ST.me)) )
+               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 == ST.me->flags))
+               sayNO;
 
-                       if (! HAS_TEXT(text_node)) c1 = c2 = -1000;
-                       else {
-                           if (PL_regkind[(U8)OP(text_node)] == REF) {
-                               c1 = c2 = -1000;
-                               goto assume_ok_REG;
-                           }
-                           else { c1 = (U8)*STRING(text_node); }
-
-                           if (OP(text_node) == EXACTF || OP(text_node) == REFF)
-                               c2 = PL_fold[c1];
-                           else if (OP(text_node) == EXACTFL || OP(text_node) == REFFL)
-                               c2 = PL_fold_locale[c1];
-                           else
-                               c2 = c1;
-                       }
-                   }
-                   else
-                       c1 = c2 = -1000;
-               }
-           assume_ok_REG:
-               REGCP_SET(lastcp);
-               while (matches >= ln) {
-                   /* If it could work, try it. */
-                   if (c1 == -1000 ||
-                       UCHARAT(PL_reginput) == c1 ||
-                       UCHARAT(PL_reginput) == c2)
+         curlym_do_B: /* execute the B in /A{m,n}B/  */
+           PL_reginput = locinput;
+           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);
+                   if (HAS_TEXT(text_node)
+                       && PL_regkind[OP(text_node)] != REF)
                    {
-                       DEBUG_EXECUTE_r(
-                           PerlIO_printf(Perl_debug_log,
-                               "%*s  trying tail with matches=%"IVdf"...\n",
-                               (int)(REPORT_CODE_OFF+PL_regindent*2),
-                               "", (IV)matches)
-                           );
-                       if (paren) {
-                           if (matches) {
-                               PL_regstartp[paren]
-                                   = HOPc(PL_reginput, -curlym_l) - PL_bostr;
-                               PL_regendp[paren] = PL_reginput - PL_bostr;
-                           }
-                           else
-                               PL_regendp[paren] = -1;
-                       }
-                       REGMATCH(next, CURLYM4);
-                       /*** all unsaved local vars undefined at this point */
-                       if (result)
-                           sayYES;
-                       REGCP_UNWIND(lastcp);
+                       ST.c1 = (U8)*STRING(text_node);
+                       ST.c2 =
+                           (OP(text_node) == EXACTF || OP(text_node) == REFF)
+                           ? PL_fold[ST.c1]
+                           : (OP(text_node) == EXACTFL || OP(text_node) == REFFL)
+                               ? PL_fold_locale[ST.c1]
+                               : ST.c1;
                    }
-                   /* Couldn't or didn't -- back up. */
-                   matches--;
-                   locinput = HOPc(locinput, -curlym_l);
-                   PL_reginput = locinput;
                }
            }
-           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 (ST.c1 != CHRTEST_VOID
+                   && UCHARAT(PL_reginput) != ST.c1
+                   && UCHARAT(PL_reginput) != ST.c2)
+           {
+               /* simulate B failing */
+               state_num = CURLYM_B_fail;
+               goto reenter_switch;
+           }
+
+           if (ST.me->flags) {
+               /* mark current A as captured */
+               I32 paren = ST.me->flags;
+               if (ST.count) {
+                   PL_regstartp[paren]
+                       = HOPc(PL_reginput, -ST.alen) - PL_bostr;
+                   PL_regendp[paren] = PL_reginput - PL_bostr;
+                   /*dmq: *PL_reglastcloseparen = paren; */
+               }
+               else
+                   PL_regendp[paren] = -1;
+               if (cur_eval && cur_eval->u.eval.close_paren &&
+                   cur_eval->u.eval.close_paren == ST.me->flags) 
+               {
+                   if (ST.count) 
+                       goto fake_end;
+                   else
+                       sayNO;
+               }
+           }
+           
+           PUSH_STATE_GOTO(CURLYM_B, ST.B); /* match B */
            /* NOTREACHED */
-           break;
-       }
-       case CURLYN:
-           paren = scan->flags;        /* Which paren to set */
-           if (paren > PL_regsize)
-               PL_regsize = paren;
-           if (paren > (I32)*PL_reglastparen)
-               *PL_reglastparen = paren;
-           ln = ARG1(scan);  /* min to match */
-           n  = ARG2(scan);  /* max to match */
-            scan = regnext(NEXTOPER(scan) + NODE_STEP_REGNODE);
-           goto repeat;
-       case CURLY:
-           paren = 0;
-           ln = ARG1(scan);  /* min to match */
-           n  = ARG2(scan);  /* max to match */
-           scan = NEXTOPER(scan) + NODE_STEP_REGNODE;
-           goto repeat;
-       case STAR:
-           ln = 0;
-           n = REG_INFTY;
+
+       case CURLYM_B_fail: /* just failed to match a B */
+           REGCP_UNWIND(ST.cp);
+           if (ST.minmod) {
+               if (ST.count == ARG2(ST.me) /* 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--;
+           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) { \
+           PL_regstartp[paren] = HOPc(locinput, -1) - PL_bostr; \
+           PL_regendp[paren] = locinput - PL_bostr; \
+           *PL_reglastcloseparen = paren; \
+       } \
+       else \
+           PL_regendp[paren] = -1; \
+    }
+
+       case STAR:              /*  /A*B/ where A is width 1 */
+           ST.paren = 0;
+           ST.min = 0;
+           ST.max = REG_INFTY;
            scan = NEXTOPER(scan);
-           paren = 0;
            goto repeat;
-       case PLUS:
-           ln = 1;
-           n = REG_INFTY;
+       case PLUS:              /*  /A+B/ where A is width 1 */
+           ST.paren = 0;
+           ST.min = 1;
+           ST.max = REG_INFTY;
            scan = NEXTOPER(scan);
-           paren = 0;
+           goto repeat;
+       case CURLYN:            /*  /(A){m,n}B/ where A is width 1 */
+           ST.paren = scan->flags;     /* Which paren to set */
+           if (ST.paren > PL_regsize)
+               PL_regsize = ST.paren;
+           if (ST.paren > (I32)*PL_reglastparen)
+               *PL_reglastparen = 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 == 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 */
+           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
            */
 
+           if (ST.min > ST.max) /* XXX make this a compile-time check? */
+               sayNO;
            if (HAS_TEXT(next) || JUMPABLE(next)) {
                U8 *s;
                regnode *text_node = next;
 
-               if (! HAS_TEXT(text_node)) FIND_NEXT_IMPT(text_node);
+               if (! HAS_TEXT(text_node)) 
+                   FIND_NEXT_IMPT(text_node);
 
-               if (! HAS_TEXT(text_node)) c1 = c2 = -1000;
+               if (! HAS_TEXT(text_node))
+                   ST.c1 = ST.c2 = CHRTEST_VOID;
                else {
-                   if (PL_regkind[(U8)OP(text_node)] == REF) {
-                       c1 = c2 = -1000;
+                   if (PL_regkind[OP(text_node)] == REF) {
+                       ST.c1 = ST.c2 = CHRTEST_VOID;
                        goto assume_ok_easy;
                    }
-                   else { s = (U8*)STRING(text_node); }
+                   else
+                       s = (U8*)STRING(text_node);
 
                    if (!UTF) {
-                       c2 = c1 = *s;
+                       ST.c2 = ST.c1 = *s;
                        if (OP(text_node) == EXACTF || OP(text_node) == REFF)
-                           c2 = PL_fold[c1];
+                           ST.c2 = PL_fold[ST.c1];
                        else if (OP(text_node) == EXACTFL || OP(text_node) == REFFL)
-                           c2 = PL_fold_locale[c1];
+                           ST.c2 = PL_fold_locale[ST.c1];
                    }
                    else { /* UTF */
                        if (OP(text_node) == EXACTF || OP(text_node) == REFF) {
@@ -4113,300 +4260,353 @@ S_regmatch(pTHX_ regnode *prog)
 
                             to_utf8_lower((U8*)s, tmpbuf1, &ulen1);
                             to_utf8_upper((U8*)s, tmpbuf2, &ulen2);
-
-                            c1 = utf8n_to_uvuni(tmpbuf1, UTF8_MAXBYTES, 0,
-                                                uniflags);
-                            c2 = utf8n_to_uvuni(tmpbuf2, UTF8_MAXBYTES, 0,
-                                                uniflags);
+#ifdef EBCDIC
+                            ST.c1 = utf8n_to_uvchr(tmpbuf1, UTF8_MAXLEN, 0,
+                                                   ckWARN(WARN_UTF8) ?
+                                                    0 : UTF8_ALLOW_ANY);
+                            ST.c2 = utf8n_to_uvchr(tmpbuf2, UTF8_MAXLEN, 0,
+                                                    ckWARN(WARN_UTF8) ?
+                                                    0 : UTF8_ALLOW_ANY);
+#else
+                            ST.c1 = utf8n_to_uvuni(tmpbuf1, UTF8_MAXBYTES, 0,
+                                                   uniflags);
+                            ST.c2 = utf8n_to_uvuni(tmpbuf2, UTF8_MAXBYTES, 0,
+                                                   uniflags);
+#endif
                        }
                        else {
-                           c2 = c1 = utf8n_to_uvchr(s, UTF8_MAXBYTES, 0,
+                           ST.c2 = ST.c1 = utf8n_to_uvchr(s, UTF8_MAXBYTES, 0,
                                                     uniflags);
                        }
                    }
                }
            }
            else
-               c1 = c2 = -1000;
+               ST.c1 = ST.c2 = CHRTEST_VOID;
        assume_ok_easy:
+
+           ST.A = scan;
+           ST.B = next;
            PL_reginput = locinput;
            if (minmod) {
                minmod = 0;
-               if (ln && regrepeat(scan, ln) < ln)
+               if (ST.min && regrepeat(rex, ST.A, ST.min) < ST.min)
                    sayNO;
+               ST.count = ST.min;
                locinput = PL_reginput;
-               REGCP_SET(lastcp);
-               if (c1 != -1000) {
-                   old = locinput;
-                   count = 0;
-
-                   if  (n == REG_INFTY) {
-                       e = PL_regeol - 1;
-                       if (do_utf8)
-                           while (UTF8_IS_CONTINUATION(*(U8*)e))
-                               e--;
-                   }
-                   else if (do_utf8) {
-                       int m = n - ln;
-                       for (e = locinput;
-                            m >0 && e + UTF8SKIP(e) <= PL_regeol; m--)
-                           e += UTF8SKIP(e);
+               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 (do_utf8)
+                       while (UTF8_IS_CONTINUATION(*(U8*)ST.maxpos))
+                           ST.maxpos--;
+               }
+               else if (do_utf8) {
+                   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 {
+               ST.count = regrepeat(rex, ST.A, ST.max);
+               locinput = PL_reginput;
+               if (ST.count < ST.min)
+                   sayNO;
+               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(PL_reginput - 1) == '\n' && OP(ST.B) != EOS)
+                       ST.min--;
+               }
+               REGCP_SET(ST.cp);
+               goto curly_try_B_max;
+           }
+           /* NOTREACHED */
+
+
+       case CURLY_B_min_known_fail:
+           /* failed to find B in a non-greedy match where c1,c2 valid */
+           if (ST.paren && ST.count)
+               PL_regendp[ST.paren] = -1;
+
+           PL_reginput = locinput;     /* Could be reset... */
+           REGCP_UNWIND(ST.cp);
+           /* Couldn't or didn't -- move forward. */
+           ST.oldloc = locinput;
+           if (do_utf8)
+               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 (do_utf8) {
+                   n = (ST.oldloc == locinput) ? 0 : 1;
+                   if (ST.c1 == ST.c2) {
+                       STRLEN len;
+                       /* set n to utf8_distance(oldloc, locinput) */
+                       while (locinput <= ST.maxpos &&
+                              utf8n_to_uvchr((U8*)locinput,
+                                             UTF8_MAXBYTES, &len,
+                                             uniflags) != (UV)ST.c1) {
+                           locinput += len;
+                           n++;
+                       }
                    }
                    else {
-                       e = locinput + n - ln;
-                       if (e >= PL_regeol)
-                           e = PL_regeol - 1;
-                   }
-                   while (1) {
-                       /* Find place 'next' could work */
-                       if (!do_utf8) {
-                           if (c1 == c2) {
-                               while (locinput <= e &&
-                                      UCHARAT(locinput) != c1)
-                                   locinput++;
-                           } else {
-                               while (locinput <= e
-                                      && UCHARAT(locinput) != c1
-                                      && UCHARAT(locinput) != c2)
-                                   locinput++;
-                           }
-                           count = locinput - old;
-                       }
-                       else {
-                           if (c1 == c2) {
-                               STRLEN len;
-                               /* count initialised to
-                                * utf8_distance(old, locinput) */
-                               while (locinput <= e &&
-                                      utf8n_to_uvchr((U8*)locinput,
-                                                     UTF8_MAXBYTES, &len,
-                                                     uniflags) != (UV)c1) {
-                                   locinput += len;
-                                   count++;
-                               }
-                           } else {
-                               STRLEN len;
-                               /* count initialised to
-                                * utf8_distance(old, locinput) */
-                               while (locinput <= e) {
-                                   UV c = utf8n_to_uvchr((U8*)locinput,
-                                                         UTF8_MAXBYTES, &len,
-                                                         uniflags);
-                                   if (c == (UV)c1 || c == (UV)c2)
-                                       break;
-                                   locinput += len;
-                                   count++;
-                               }
-                           }
-                       }
-                       if (locinput > e)
-                           sayNO;
-                       /* PL_reginput == old now */
-                       if (locinput != old) {
-                           ln = 1;     /* Did some */
-                           if (regrepeat(scan, count) < count)
-                               sayNO;
+                       /* set n to utf8_distance(oldloc, locinput) */
+                       while (locinput <= ST.maxpos) {
+                           STRLEN len;
+                           const UV c = utf8n_to_uvchr((U8*)locinput,
+                                                 UTF8_MAXBYTES, &len,
+                                                 uniflags);
+                           if (c == (UV)ST.c1 || c == (UV)ST.c2)
+                               break;
+                           locinput += len;
+                           n++;
                        }
-                       /* PL_reginput == locinput now */
-                       TRYPAREN(paren, ln, locinput, PLUS1);
-                       /*** all unsaved local vars undefined at this point */
-                       PL_reginput = locinput; /* Could be reset... */
-                       REGCP_UNWIND(lastcp);
-                       /* Couldn't or didn't -- move forward. */
-                       old = locinput;
-                       if (do_utf8)
-                           locinput += UTF8SKIP(locinput);
-                       else
-                           locinput++;
-                       count = 1;
                    }
                }
-               else
-               while (n >= ln || (n == REG_INFTY && ln > 0)) { /* ln overflow ? */
-                   UV c;
-                   if (c1 != -1000) {
-                       if (do_utf8)
-                           c = utf8n_to_uvchr((U8*)PL_reginput,
-                                              UTF8_MAXBYTES, 0,
-                                              uniflags);
-                       else
-                           c = UCHARAT(PL_reginput);
-                       /* If it could work, try it. */
-                       if (c == (UV)c1 || c == (UV)c2)
-                       {
-                           TRYPAREN(paren, ln, PL_reginput, PLUS2);
-                           /*** all unsaved local vars undefined at this point */
-                           REGCP_UNWIND(lastcp);
-                       }
-                   }
-                   /* If it could work, try it. */
-                   else if (c1 == -1000)
-                   {
-                       TRYPAREN(paren, ln, PL_reginput, PLUS3);
-                       /*** all unsaved local vars undefined at this point */
-                       REGCP_UNWIND(lastcp);
+               else {
+                   if (ST.c1 == ST.c2) {
+                       while (locinput <= ST.maxpos &&
+                              UCHARAT(locinput) != ST.c1)
+                           locinput++;
                    }
-                   /* Couldn't or didn't -- move forward. */
-                   PL_reginput = locinput;
-                   if (regrepeat(scan, 1)) {
-                       ln++;
-                       locinput = PL_reginput;
+                   else {
+                       while (locinput <= ST.maxpos
+                              && UCHARAT(locinput) != ST.c1
+                              && UCHARAT(locinput) != ST.c2)
+                           locinput++;
                    }
-                   else
+                   n = locinput - ST.oldloc;
+               }
+               if (locinput > ST.maxpos)
+                   sayNO;
+               /* PL_reginput == oldloc now */
+               if (n) {
+                   ST.count += n;
+                   if (regrepeat(rex, ST.A, n) < n)
                        sayNO;
                }
+               PL_reginput = locinput;
+               CURLY_SETPAREN(ST.paren, ST.count);
+               if (cur_eval && cur_eval->u.eval.close_paren && 
+                   cur_eval->u.eval.close_paren == ST.paren) {
+                   goto fake_end;
+               }
+               PUSH_STATE_GOTO(CURLY_B_min_known, ST.B);
            }
-           else {
-               n = regrepeat(scan, n);
+           /* NOTREACHED */
+
+
+       case CURLY_B_min_fail:
+           /* failed to find B in a non-greedy match where c1,c2 invalid */
+           if (ST.paren && ST.count)
+               PL_regendp[ST.paren] = -1;
+
+           REGCP_UNWIND(ST.cp);
+           /* failed -- move forward one */
+           PL_reginput = locinput;
+           if (regrepeat(rex, ST.A, 1)) {
+               ST.count++;
                locinput = PL_reginput;
-               if (ln < n && PL_regkind[(U8)OP(next)] == EOL &&
-                   (OP(next) != MEOL ||
-                       OP(next) == SEOL || OP(next) == EOS))
-               {
-                   ln = n;                     /* why back off? */
-                   /* ...because $ and \Z can match before *and* after
-                      newline at the end.  Consider "\n\n" =~ /\n+\Z\n/.
-                      We should back off by one in this case. */
-                   if (UCHARAT(PL_reginput - 1) == '\n' && OP(next) != EOS)
-                       ln--;
-               }
-               REGCP_SET(lastcp);
+               if (ST.count <= ST.max || (ST.max == REG_INFTY &&
+                       ST.count > 0)) /* count overflow ? */
                {
-                   UV c = 0;
-                   while (n >= ln) {
-                       if (c1 != -1000) {
-                           if (do_utf8)
-                               c = utf8n_to_uvchr((U8*)PL_reginput,
-                                                  UTF8_MAXBYTES, 0,
-                                                  uniflags);
-                           else
-                               c = UCHARAT(PL_reginput);
-                       }
-                       /* If it could work, try it. */
-                       if (c1 == -1000 || c == (UV)c1 || c == (UV)c2)
-                           {
-                               TRYPAREN(paren, n, PL_reginput, PLUS4);
-                               /*** all unsaved local vars undefined at this point */
-                               REGCP_UNWIND(lastcp);
-                           }
-                       /* Couldn't or didn't -- back up. */
-                       n--;
-                       PL_reginput = locinput = HOPc(locinput, -1);
-                   }
+                 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 == ST.paren) {
+                        goto fake_end;
+                    }
+                   PUSH_STATE_GOTO(CURLY_B_min, ST.B);
                }
            }
            sayNO;
-           break;
-       case END:
-           if (PL_reg_call_cc) {
-               cur_call_cc = PL_reg_call_cc;
-               end_re = PL_reg_re;
+           /* NOTREACHED */
 
-               /* Save *all* the positions. */
-               cp = regcppush(0);
-               REGCP_SET(lastcp);
 
-               /* Restore parens of the caller. */
-               {
-                   I32 tmp = PL_savestack_ix;
-                   PL_savestack_ix = PL_reg_call_cc->ss;
-                   regcppop();
-                   PL_savestack_ix = tmp;
+       curly_try_B_max:
+           /* a successful greedy match: now try to match B */
+           {
+               UV c = 0;
+               if (ST.c1 != CHRTEST_VOID)
+                   c = do_utf8 ? utf8n_to_uvchr((U8*)PL_reginput,
+                                          UTF8_MAXBYTES, 0, uniflags)
+                               : (UV) UCHARAT(PL_reginput);
+               /* If it could work, try it. */
+               if (ST.c1 == CHRTEST_VOID || c == (UV)ST.c1 || c == (UV)ST.c2) {
+                   CURLY_SETPAREN(ST.paren, ST.count);
+                   if (cur_eval && cur_eval->u.eval.close_paren &&
+                       cur_eval->u.eval.close_paren == ST.paren) {
+                        goto fake_end;
+                    }
+                   PUSH_STATE_GOTO(CURLY_B_max, ST.B);
+                   /* NOTREACHED */
                }
+           }
+           /* FALL THROUGH */
+       case CURLY_B_max_fail:
+           /* failed to find B in a greedy match */
+           if (ST.paren && ST.count)
+               PL_regendp[ST.paren] = -1;
+
+           REGCP_UNWIND(ST.cp);
+           /*  back up. */
+           if (--ST.count < ST.min)
+               sayNO;
+           PL_reginput = locinput = HOPc(locinput, -1);
+           goto curly_try_B_max;
 
-               /* Make position available to the callcc. */
+#undef ST
+
+
+       case END:
+           fake_end:
+           if (cur_eval) {
+               /* we've just finished A in /(??{A})B/; now continue with B */
+               I32 tmpix;
+
+
+               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;              /* inner */
+               rex    = cur_eval->u.eval.prev_rex;     /* outer */
+               cur_curlyx = cur_eval->u.eval.prev_curlyx;
+               ReREFCNT_inc(rex);
+               st->u.eval.cp = regcppush(0);   /* Save *all* the positions. */
+               REGCP_SET(st->u.eval.lastcp);
                PL_reginput = locinput;
 
-               cache_re(PL_reg_call_cc->re);
-               oldcc = cc;
-               cc = PL_reg_call_cc->cc;
-               PL_reg_call_cc = PL_reg_call_cc->prev;
-               REGMATCH(cur_call_cc->node, END);
-               /*** all unsaved local vars undefined at this point */
-               if (result) {
-                   PL_reg_call_cc = cur_call_cc;
-                   regcpblow(cp);
-                   sayYES;
-               }
-               REGCP_UNWIND(lastcp);
-               regcppop();
-               PL_reg_call_cc = cur_call_cc;
-               cc = oldcc;
-               PL_reg_re = end_re;
-               cache_re(end_re);
+               /* Restore parens of the outer rex without popping the
+                * savestack */
+               tmpix = PL_savestack_ix;
+               PL_savestack_ix = cur_eval->u.eval.lastcp;
+               regcppop(rex);
+               PL_savestack_ix = tmpix;
 
+               st->u.eval.prev_eval = cur_eval;
+               cur_eval = cur_eval->u.eval.prev_eval;
                DEBUG_EXECUTE_r(
-                   PerlIO_printf(Perl_debug_log,
-                                 "%*s  continuation failed...\n",
-                                 REPORT_CODE_OFF+PL_regindent*2, "")
-                   );
-               sayNO_SILENT;
+                   PerlIO_printf(Perl_debug_log, "%*s  EVAL trying tail ... %x\n",
+                                     REPORT_CODE_OFF+depth*2, "",(int)cur_eval););
+               PUSH_YES_STATE_GOTO(EVAL_AB,
+                       st->u.eval.prev_eval->u.eval.B); /* match B */
            }
-           if (locinput < PL_regtill) {
+
+           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)(PL_regtill - PL_reg_starttry),
+                                     (long)(reginfo->till - PL_reg_starttry),
                                      PL_colors[5]));
-               sayNO_FINAL;            /* Cannot match: too short. */
+               sayNO_SILENT;           /* Cannot match: too short. */
            }
            PL_reginput = locinput;     /* put where regtry can find it */
-           sayYES_FINAL;               /* Success! */
-       case SUCCEED:
+           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]));
            PL_reginput = locinput;     /* put where regtry can find it */
-           sayYES_LOUD;                /* Success! */
-       case SUSPEND:
-           n = 1;
+           sayYES;                     /* Success! */
+
+#undef  ST
+#define ST st->u.ifmatch
+
+       case SUSPEND:   /* (?>A) */
+           ST.wanted = 1;
            PL_reginput = locinput;
            goto do_ifmatch;    
-       case UNLESSM:
-           n = 0;
-           if (scan->flags) {
-               char *s = HOPBACKc(locinput, scan->flags);
-               if (!s)
-                   goto say_yes;
-               PL_reginput = s;
-           }
-           else
-               PL_reginput = locinput;
-           goto do_ifmatch;
-       case IFMATCH:
-           n = 1;
+
+       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 *s = HOPBACKc(locinput, scan->flags);
-               if (!s)
-                   goto say_no;
+               char * const s = HOPBACKc(locinput, scan->flags);
+               if (!s) {
+                   /* trivial fail */
+                   if (logical) {
+                       logical = 0;
+                       sw = 1 - (bool)ST.wanted;
+                   }
+                   else if (ST.wanted)
+                       sayNO;
+                   next = scan + ARG(scan);
+                   if (next == scan)
+                       next = NULL;
+                   break;
+               }
                PL_reginput = s;
            }
            else
                PL_reginput = locinput;
 
          do_ifmatch:
-           REGMATCH(NEXTOPER(NEXTOPER(scan)), IFMATCH);
-           /*** all unsaved local vars undefined at this point */
-           if (result != n) {
-             say_no:
-               if (logical) {
-                   logical = 0;
-                   sw = 0;
-                   goto do_longjump;
-               }
-               else
-                   sayNO;
-           }
-         say_yes:
-           if (logical) {
-               logical = 0;
-               sw = 1;
+           ST.me = scan;
+           ST.logical = logical;
+           /* execute body of (?...A) */
+           PUSH_YES_STATE_GOTO(IFMATCH_A, NEXTOPER(NEXTOPER(scan)));
+           /* 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 = (bool)ST.wanted;
            }
-           if (OP(scan) == SUSPEND) {
+           else if (!ST.wanted)
+               sayNO;
+
+           if (OP(ST.me) == SUSPEND)
                locinput = PL_reginput;
+           else {
+               locinput = PL_reginput = st->locinput;
                nextchr = UCHARAT(locinput);
            }
-           /* FALL THROUGH. */
+           scan = ST.me + ARG(ST.me);
+           if (scan == ST.me)
+               scan = NULL;
+           continue; /* execute B */
+
+#undef ST
+
        case LONGJMP:
-         do_longjump:
            next = scan + ARG(scan);
            if (next == scan)
                next = NULL;
@@ -4417,66 +4617,33 @@ S_regmatch(pTHX_ regnode *prog)
            Perl_croak(aTHX_ "regexp memory corruption");
        }
 
-      reenter:
        scan = next;
        continue;
        /* NOTREACHED */
 
-       /* simulate recursively calling regmatch(), but without actually
-        * recursing - ie save the current state on the heap rather than on
-        * the stack, then re-enter the loop. This avoids complex regexes
-        * blowing the processor stack */
-
-      start_recurse:
+      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  */
        {
-           /* save existing local variables */
-           struct regmatch_state *p;
-
-           Newx(p, 1, struct regmatch_state);
-           p->prev_state = prev_state;
-           prev_state = p;
-           p->resume_state = resume_state;
-           p->scan = scan;
-           p->next = next;
-           p->minmod = minmod;
-           p->sw = sw;
-           p->logical = logical;
-           p->unwind = unwind;
-           p->cc = cc;
-           p->locinput = locinput;
-           p->n = n;
-           p->ln = ln;
-           p->c1 = c1;
-           p->c2 = c2;
-           p->paren = paren;
-           p->cp = cp;
-           p->lastcp = lastcp;
-           p->oldcc = oldcc;
-           p->lastloc = lastloc;
-           p->cache_offset = cache_offset;
-           p->cache_bit = cache_bit;
-           p->curlym_l = curlym_l;
-           p->matches = matches;
-           p->maxwanted = maxwanted;
-           p->e = e;
-           p->old = old;
-           p->count = count;
-           p->cur_call_cc = cur_call_cc;
-           p->end_re = end_re;
-           p->accept_buff = accept_buff;
-           p->accepted = accepted;
-           p->reg_call_cc = PL_reg_call_cc;
-
-           scan = new_scan;
+           regmatch_state *newst;
+
+           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 = PL_reginput;
-           nextchr = UCHARAT(locinput);
-           minmod = 0;
-           sw = 0;
-           logical = 0;
-           unwind = 0;
-#ifdef DEBUGGING
-           PL_regindent++;
-#endif
+           nextchr = UCHARAT(locinput);
+           st = newst;
+           continue;
+           /* NOTREACHED */
        }
     }
 
@@ -4488,170 +4655,94 @@ S_regmatch(pTHX_ regnode *prog)
     /*NOTREACHED*/
     sayNO;
 
-yes_loud:
-    DEBUG_EXECUTE_r(
-       PerlIO_printf(Perl_debug_log,
-                     "%*s  %scould match...%s\n",
-                     REPORT_CODE_OFF+PL_regindent*2, "", PL_colors[4], PL_colors[5])
-       );
-    goto yes;
-yes_final:
-    DEBUG_EXECUTE_r(PerlIO_printf(Perl_debug_log, "%sMatch successful!%s\n",
-                         PL_colors[4], PL_colors[5]));
 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
-    PL_regindent--;
+       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_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;
+
+       state_num = st->resume_state;
+       goto reenter_switch;
+    }
+
+    DEBUG_EXECUTE_r(PerlIO_printf(Perl_debug_log, "%sMatch successful!%s\n",
+                         PL_colors[4], PL_colors[5]));
 
     result = 1;
-    goto exit_level;
+    goto final_exit;
 
 no:
     DEBUG_EXECUTE_r(
        PerlIO_printf(Perl_debug_log,
-                     "%*s  %sfailed...%s\n",
-                     REPORT_CODE_OFF+PL_regindent*2, "", PL_colors[4], PL_colors[5])
+            "%*s  %sfailed...%s\n",
+            REPORT_CODE_OFF+depth*2, "", 
+            PL_colors[4], PL_colors[5])
        );
-    goto do_no;
-no_final:
-do_no:
-    if (unwind) {
-       re_unwind_t * const uw = SSPTRt(unwind,re_unwind_t);
-
-       switch (uw->type) {
-       case RE_UNWIND_BRANCH:
-       case RE_UNWIND_BRANCHJ:
-       {
-           re_unwind_branch_t * const uwb = &(uw->branch);
-           const I32 lastparen = uwb->lastparen;
-       
-           REGCP_UNWIND(uwb->lastcp);
-           for (n = *PL_reglastparen; n > lastparen; n--)
-               PL_regendp[n] = -1;
-           *PL_reglastparen = n;
-           scan = next = uwb->next;
-           if ( !scan ||
-                OP(scan) != (uwb->type == RE_UNWIND_BRANCH
-                             ? BRANCH : BRANCHJ) ) {           /* Failure */
-               unwind = uwb->prev;
-#ifdef DEBUGGING
-               PL_regindent--;
-#endif
-               goto do_no;
-           }
-           /* Have more choice yet.  Reuse the same uwb.  */
-           if ((n = (uwb->type == RE_UNWIND_BRANCH
-                     ? NEXT_OFF(next) : ARG(next))))
-               next += n;
-           else
-               next = NULL;    /* XXXX Needn't unwinding in this case... */
-           uwb->next = next;
-           next = NEXTOPER(scan);
-           if (uwb->type == RE_UNWIND_BRANCHJ)
-               next = NEXTOPER(next);
-           locinput = uwb->locinput;
-           nextchr = uwb->nextchr;
-#ifdef DEBUGGING
-           PL_regindent = uwb->regindent;
-#endif
 
-           goto reenter;
-       }
-       /* NOTREACHED */
-       default:
-           Perl_croak(aTHX_ "regexp unwind memory corruption");
+no_silent:
+    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);
        }
-       /* NOTREACHED */
+       PL_regmatch_state = st;
+       locinput= st->locinput;
+       nextchr = UCHARAT(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;
     }
-#ifdef DEBUGGING
-    PL_regindent--;
-#endif
     result = 0;
-exit_level:
-    if (prev_state) {
-       /* restore previous state and re-enter */
-
-       struct regmatch_state *p = prev_state;
-       resume_state = p->resume_state;
-       scan = p->scan;
-       next = p->next;
-       minmod = p->minmod;
-       sw = p->sw;
-       logical = p->logical;
-       unwind = p->unwind;
-       cc = p->cc;
-       locinput = p->locinput;
-       nextchr = UCHARAT(locinput);
-       n = p->n;
-       ln = p->ln;
-       c1 = p->c1;
-       c2 = p->c2;
-       paren = p->paren;
-       cp = p->cp;
-       lastcp = p->lastcp;
-       oldcc = p->oldcc;
-       lastloc = p->lastloc;
-       cache_offset = p->cache_offset;
-       cache_bit = p->cache_bit;
-       curlym_l = p->curlym_l;
-       matches = p->matches;
-       maxwanted = p->maxwanted;
-       e = p->e;
-       old = p->old;
-       count = p->count;
-       cur_call_cc = p->cur_call_cc;
-       end_re = p->end_re;
-       accept_buff = p->accept_buff;
-       accepted = p->accepted;
-       PL_reg_call_cc = p->reg_call_cc;
-       prev_state = p->prev_state;
-
-       switch (resume_state) {
-       case resume_TRIE1:
-           goto resume_point_TRIE1;
-       case resume_TRIE2:
-           goto resume_point_TRIE2;
-       case resume_CURLYX:
-           goto resume_point_CURLYX;
-       case resume_WHILEM1:
-           goto resume_point_WHILEM1;
-       case resume_WHILEM2:
-           goto resume_point_WHILEM2;
-       case resume_WHILEM3:
-           goto resume_point_WHILEM3;
-       case resume_WHILEM4:
-           goto resume_point_WHILEM4;
-       case resume_WHILEM5:
-           goto resume_point_WHILEM5;
-       case resume_WHILEM6:
-           goto resume_point_WHILEM6;
-       case resume_CURLYM1:
-           goto resume_point_CURLYM1;
-       case resume_CURLYM2:
-           goto resume_point_CURLYM2;
-       case resume_CURLYM3:
-           goto resume_point_CURLYM3;
-       case resume_CURLYM4:
-           goto resume_point_CURLYM4;
-       case resume_IFMATCH:
-           goto resume_point_IFMATCH;
-       case resume_PLUS1:
-           goto resume_point_PLUS1;
-       case resume_PLUS2:
-           goto resume_point_PLUS2;
-       case resume_PLUS3:
-           goto resume_point_PLUS3;
-       case resume_PLUS4:
-           goto resume_point_PLUS4;
-       case resume_END:
-           goto resume_point_END;
-       default:
-           Perl_croak(aTHX_ "regexp resume memory corruption");
+
+  final_exit:
+
+    /* restore original high-water mark */
+    PL_regmatch_slab  = orig_slab;
+    PL_regmatch_state = orig_state;
+
+    /* free all slabs above current one */
+    if (orig_slab->next) {
+       regmatch_slab *sl = orig_slab->next;
+       orig_slab->next = NULL;
+       while (sl) {
+           regmatch_slab * const osl = sl;
+           sl = sl->next;
+           Safefree(osl);
        }
-       /* NOTREACHED */
     }
-    return result;
 
+    return result;
 }
 
 /*
@@ -4663,7 +4754,7 @@ exit_level:
  * rather than incrementing count on every character.  [Er, except utf8.]]
  */
 STATIC I32
-S_regrepeat(pTHX_ const regnode *p, I32 max)
+S_regrepeat(pTHX_ const regexp *prog, const regnode *p, I32 max)
 {
     dVAR;
     register char *scan;
@@ -4676,7 +4767,7 @@ S_regrepeat(pTHX_ const regnode *p, I32 max)
     if (max == REG_INFTY)
        max = I32_MAX;
     else if (max < loceol - scan)
-      loceol = scan + max;
+       loceol = scan + max;
     switch (OP(p)) {
     case REG_ANY:
        if (do_utf8) {
@@ -4726,12 +4817,12 @@ S_regrepeat(pTHX_ const regnode *p, I32 max)
        if (do_utf8) {
            loceol = PL_regeol;
            while (hardcount < max && scan < loceol &&
-                  reginclass(p, (U8*)scan, 0, do_utf8)) {
+                  reginclass(prog, p, (U8*)scan, 0, do_utf8)) {
                scan += UTF8SKIP(scan);
                hardcount++;
            }
        } else {
-           while (scan < loceol && REGINCLASS(p, (U8*)scan))
+           while (scan < loceol && REGINCLASS(prog, p, (U8*)scan))
                scan++;
        }
        break;
@@ -4888,38 +4979,39 @@ S_regrepeat(pTHX_ const regnode *p, I32 max)
     PL_reginput = scan;
 
     DEBUG_r({
-               SV *re_debug_flags = NULL;
-               SV * const prop = sv_newmortal();
-                GET_RE_DEBUG_FLAGS;
-                DEBUG_EXECUTE_r({
-               regprop(prop, p);
-               PerlIO_printf(Perl_debug_log,
-                             "%*s  %s can match %"IVdf" times out of %"IVdf"...\n",
-                             REPORT_CODE_OFF+1, "", SvPVX_const(prop),(IV)c,(IV)max);
-       });
+       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+1, "", 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
 */
 
 SV *
-Perl_regclass_swash(pTHX_ register const regnode* node, bool doinit, SV** listsvp, SV **altsvp)
+Perl_regclass_swash(pTHX_ const regexp *prog, register const regnode* node, bool doinit, SV** listsvp, SV **altsvp)
 {
     dVAR;
     SV *sw  = NULL;
     SV *si  = NULL;
     SV *alt = NULL;
+    const struct reg_data * const data = prog ? prog->data : NULL;
 
-    if (PL_regdata && PL_regdata->count) {
+    if (data && data->count) {
        const U32 n = ARG(node);
 
-       if (PL_regdata->what[n] == 's') {
-           SV * const rv = (SV*)PL_regdata->data[n];
+       if (data->what[n] == 's') {
+           SV * const rv = (SV*)data->data[n];
            AV * const av = (AV*)SvRV((SV*)rv);
            SV **const ary = AvARRAY(av);
            SV **a, **b;
@@ -4949,6 +5041,7 @@ Perl_regclass_swash(pTHX_ register const regnode* node, bool doinit, SV** listsv
 
     return sw;
 }
+#endif
 
 /*
  - reginclass - determine if a character falls into a character class
@@ -4961,7 +5054,7 @@ Perl_regclass_swash(pTHX_ register const regnode* node, bool doinit, SV** listsv
  */
 
 STATIC bool
-S_reginclass(pTHX_ register const regnode *n, register const U8* p, STRLEN* lenp, register bool do_utf8)
+S_reginclass(pTHX_ const regexp *prog, register const regnode *n, register const U8* p, STRLEN* lenp, register bool do_utf8)
 {
     dVAR;
     const char flags = ANYOF_FLAGS(n);
@@ -4972,9 +5065,9 @@ S_reginclass(pTHX_ register const regnode *n, register const U8* p, STRLEN* lenp
 
     if (do_utf8 && !UTF8_IS_INVARIANT(c)) {
        c = utf8n_to_uvchr(p, UTF8_MAXBYTES, &len,
-                           ckWARN(WARN_UTF8) ? UTF8_CHECK_ONLY :
-                                       UTF8_ALLOW_ANYUV|UTF8_CHECK_ONLY);
-       if (len == (STRLEN)-1)
+               (UTF8_ALLOW_DEFAULT & UTF8_ALLOW_ANYUV) | UTF8_CHECK_ONLY);
+               /* see [perl #37836] for UTF8_ALLOW_ANYUV */
+       if (len == (STRLEN)-1) 
            Perl_croak(aTHX_ "Malformed UTF-8 character (fatal)");
     }
 
@@ -4990,7 +5083,7 @@ S_reginclass(pTHX_ register const regnode *n, register const U8* p, STRLEN* lenp
            match = TRUE;
        if (!match) {
            AV *av;
-           SV * const sw = regclass_swash(n, TRUE, 0, (SV**)&av);
+           SV * const sw = regclass_swash(prog, n, TRUE, 0, (SV**)&av);
        
            if (sw) {
                if (swash_fetch(sw, p, do_utf8))
@@ -5084,14 +5177,7 @@ S_reginclass(pTHX_ register const regnode *n, register const U8* p, STRLEN* lenp
 }
 
 STATIC U8 *
-S_reghop(pTHX_ U8 *s, I32 off)
-{
-    dVAR;
-    return S_reghop3(s, off, (U8*)(off >= 0 ? PL_regeol : PL_bostr));
-}
-
-STATIC U8 *
-S_reghop3(U8 *s, I32 off, U8* lim)
+S_reghop3(U8 *s, I32 off, const U8* lim)
 {
     dVAR;
     if (off >= 0) {
@@ -5101,29 +5187,49 @@ S_reghop3(U8 *s, I32 off, U8* lim)
        }
     }
     else {
-       while (off++) {
-           if (s > lim) {
-               s--;
-               if (UTF8_IS_CONTINUED(*s)) {
-                   while (s > (U8*)lim && UTF8_IS_CONTINUATION(*s))
-                       s--;
-               }
-               /* XXX could check well-formedness here */
+        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_reghopmaybe(pTHX_ U8 *s, I32 off)
+S_reghop4(U8 *s, I32 off, const U8* llim, const U8* rlim)
 {
     dVAR;
-    return S_reghopmaybe3(s, off, (U8*)(off >= 0 ? PL_regeol : PL_bostr));
+    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, U8* lim)
+S_reghopmaybe3(U8* s, I32 off, const U8* lim)
 {
     dVAR;
     if (off >= 0) {
@@ -5132,23 +5238,19 @@ S_reghopmaybe3(U8* s, I32 off, U8* lim)
            s += UTF8SKIP(s);
        }
        if (off >= 0)
-           return 0;
+           return NULL;
     }
     else {
-       while (off++) {
-           if (s > lim) {
-               s--;
-               if (UTF8_IS_CONTINUED(*s)) {
-                   while (s > (U8*)lim && UTF8_IS_CONTINUATION(*s))
-                       s--;
-               }
-               /* XXX could check well-formedness here */
+        while (off++ && s > lim) {
+            s--;
+            if (UTF8_IS_CONTINUED(*s)) {
+                while (s > lim && UTF8_IS_CONTINUATION(*s))
+                    s--;
            }
-           else
-               break;
+            /* XXX could check well-formedness here */
        }
        if (off <= 0)
-           return 0;
+           return NULL;
     }
     return s;
 }
@@ -5157,15 +5259,15 @@ static void
 restore_pos(pTHX_ void *arg)
 {
     dVAR;
-    PERL_UNUSED_ARG(arg);
+    regexp * const rex = (regexp *)arg;
     if (PL_reg_eval_set) {
        if (PL_reg_oldsaved) {
-           PL_reg_re->subbeg = PL_reg_oldsaved;
-           PL_reg_re->sublen = PL_reg_oldsavedlen;
+           rex->subbeg = PL_reg_oldsaved;
+           rex->sublen = PL_reg_oldsavedlen;
 #ifdef PERL_OLD_COPY_ON_WRITE
-           PL_reg_re->saved_copy = PL_nrs;
+           rex->saved_copy = PL_nrs;
 #endif
-           RX_MATCH_COPIED_on(PL_reg_re);
+           RX_MATCH_COPIED_on(rex);
        }
        PL_reg_magic->mg_len = PL_reg_oldpos;
        PL_reg_eval_set = 0;
@@ -5177,8 +5279,8 @@ STATIC void
 S_to_utf8_substr(pTHX_ register regexp *prog)
 {
     if (prog->float_substr && !prog->float_utf8) {
-       SV* sv;
-       prog->float_utf8 = sv = newSVsv(prog->float_substr);
+       SV* const sv = newSVsv(prog->float_substr);
+       prog->float_utf8 = sv;
        sv_utf8_upgrade(sv);
        if (SvTAIL(prog->float_substr))
            SvTAIL_on(sv);
@@ -5186,8 +5288,8 @@ S_to_utf8_substr(pTHX_ register regexp *prog)
            prog->check_utf8 = sv;
     }
     if (prog->anchored_substr && !prog->anchored_utf8) {
-       SV* sv;
-       prog->anchored_utf8 = sv = newSVsv(prog->anchored_substr);
+       SV* const sv = newSVsv(prog->anchored_substr);
+       prog->anchored_utf8 = sv;
        sv_utf8_upgrade(sv);
        if (SvTAIL(prog->anchored_substr))
            SvTAIL_on(sv);
@@ -5201,8 +5303,8 @@ S_to_byte_substr(pTHX_ register regexp *prog)
 {
     dVAR;
     if (prog->float_utf8 && !prog->float_substr) {
-       SV* sv;
-       prog->float_substr = sv = newSVsv(prog->float_utf8);
+       SV* sv = newSVsv(prog->float_utf8);
+       prog->float_substr = sv;
        if (sv_utf8_downgrade(sv, TRUE)) {
            if (SvTAIL(prog->float_utf8))
                SvTAIL_on(sv);
@@ -5214,8 +5316,8 @@ S_to_byte_substr(pTHX_ register regexp *prog)
            prog->check_substr = sv;
     }
     if (prog->anchored_utf8 && !prog->anchored_substr) {
-       SV* sv;
-       prog->anchored_substr = sv = newSVsv(prog->anchored_utf8);
+       SV* sv = newSVsv(prog->anchored_utf8);
+       prog->anchored_substr = sv;
        if (sv_utf8_downgrade(sv, TRUE)) {
            if (SvTAIL(prog->anchored_utf8))
                SvTAIL_on(sv);