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regexec.c: Clarify comments; remove stray ';'
[perl5.git] / regexec.c
index 6c5f8a6..018bebd 100644 (file)
--- a/regexec.c
+++ b/regexec.c
@@ -96,6 +96,12 @@ static const char* const non_utf8_target_but_utf8_required
                 = "Can't match, because target string needs to be in UTF-8\n";
 #endif
 
+/* Returns a boolean as to whether the input unsigned number is a power of 2
+ * (2**0, 2**1, etc).  In other words if it has just a single bit set.
+ * If not, subtracting 1 would leave the uppermost bit set, so the & would
+ * yield non-zero */
+#define isPOWER_OF_2(n) ((n & (n-1)) == 0)
+
 #define NON_UTF8_TARGET_BUT_UTF8_REQUIRED(target) STMT_START {           \
     DEBUG_EXECUTE_r(Perl_re_printf( aTHX_  "%s", non_utf8_target_but_utf8_required));\
     goto target;                                                         \
@@ -119,7 +125,6 @@ static const char* const non_utf8_target_but_utf8_required
  */
 
 #define CHR_SVLEN(sv) (utf8_target ? sv_len_utf8(sv) : SvCUR(sv))
-#define CHR_DIST(a,b) (reginfo->is_utf8_target ? utf8_distance(a,b) : a - b)
 
 #define HOPc(pos,off) \
        (char *)(reginfo->is_utf8_target \
@@ -127,13 +132,16 @@ static const char* const non_utf8_target_but_utf8_required
                     (U8*)(off >= 0 ? reginfo->strend : reginfo->strbeg)) \
            : (U8*)(pos + off))
 
-#define HOPBACKc(pos, off) \
-       (char*)(reginfo->is_utf8_target \
-           ? reghopmaybe3((U8*)pos, (SSize_t)0-off, (U8*)(reginfo->strbeg)) \
-           : (pos - off >= reginfo->strbeg)    \
-               ? (U8*)pos - off                \
+/* like HOPMAYBE3 but backwards. lim must be +ve. Returns NULL on overshoot */
+#define HOPBACK3(pos, off, lim) \
+       (reginfo->is_utf8_target                          \
+           ? reghopmaybe3((U8*)pos, (SSize_t)0-off, (U8*)(lim)) \
+           : (pos - off >= lim)                                 \
+               ? (U8*)pos - off                                 \
                : NULL)
 
+#define HOPBACKc(pos, off) ((char*)HOPBACK3(pos, off, reginfo->strbeg))
+
 #define HOP3(pos,off,lim) (reginfo->is_utf8_target  ? reghop3((U8*)(pos), off, (U8*)(lim)) : (U8*)(pos + off))
 #define HOP3c(pos,off,lim) ((char*)HOP3(pos,off,lim))
 
@@ -150,6 +158,7 @@ static const char* const non_utf8_target_but_utf8_required
 #define HOP3lim(pos,off,lim) (reginfo->is_utf8_target \
     ? reghop3((U8*)(pos), off, (U8*)(lim)) \
     : (U8*)((pos + off) > lim ? lim : (pos + off)))
+#define HOP3clim(pos,off,lim) ((char*)HOP3lim(pos,off,lim))
 
 #define HOP4(pos,off,llim, rlim) (reginfo->is_utf8_target \
     ? reghop4((U8*)(pos), off, (U8*)(llim), (U8*)(rlim)) \
@@ -272,7 +281,7 @@ static regmatch_state * S_push_slab(pTHX);
  * are needed for the regexp context stack bookkeeping. */
 
 STATIC CHECKPOINT
-S_regcppush(pTHX_ const regexp *rex, I32 parenfloor, U32 maxopenparen)
+S_regcppush(pTHX_ const regexp *rex, I32 parenfloor, U32 maxopenparen _pDEPTH)
 {
     const int retval = PL_savestack_ix;
     const int paren_elems_to_push =
@@ -290,7 +299,7 @@ S_regcppush(pTHX_ const regexp *rex, I32 parenfloor, U32 maxopenparen)
                    (int)parenfloor, (unsigned)REGCP_PAREN_ELEMS);
 
     if ((elems_shifted >> SAVE_TIGHT_SHIFT) != total_elems)
-       Perl_croak(aTHX_ "panic: paren_elems_to_push offset %"UVuf
+       Perl_croak(aTHX_ "panic: paren_elems_to_push offset %" UVuf
                   " out of range (%lu-%ld)",
                   total_elems,
                    (unsigned long)maxopenparen,
@@ -300,9 +309,10 @@ S_regcppush(pTHX_ const regexp *rex, I32 parenfloor, U32 maxopenparen)
     
     DEBUG_BUFFERS_r(
        if ((int)maxopenparen > (int)parenfloor)
-            Perl_re_printf( aTHX_
-               "rex=0x%"UVxf" offs=0x%"UVxf": saving capture indices:\n",
-               PTR2UV(rex),
+            Perl_re_exec_indentf( aTHX_
+               "rex=0x%" UVxf " offs=0x%" UVxf ": saving capture indices:\n",
+               depth,
+                PTR2UV(rex),
                PTR2UV(rex->offs)
            );
     );
@@ -311,9 +321,10 @@ S_regcppush(pTHX_ const regexp *rex, I32 parenfloor, U32 maxopenparen)
        SSPUSHIV(rex->offs[p].end);
        SSPUSHIV(rex->offs[p].start);
        SSPUSHINT(rex->offs[p].start_tmp);
-        DEBUG_BUFFERS_r(Perl_re_printf( aTHX_
-           "    \\%"UVuf": %"IVdf"(%"IVdf")..%"IVdf"\n",
-           (UV)p,
+        DEBUG_BUFFERS_r(Perl_re_exec_indentf( aTHX_
+           "    \\%" UVuf ": %" IVdf "(%" IVdf ")..%" IVdf "\n",
+           depth,
+            (UV)p,
            (IV)rex->offs[p].start,
            (IV)rex->offs[p].start_tmp,
            (IV)rex->offs[p].end
@@ -331,8 +342,8 @@ S_regcppush(pTHX_ const regexp *rex, I32 parenfloor, U32 maxopenparen)
 /* These are needed since we do not localize EVAL nodes: */
 #define REGCP_SET(cp)                                           \
     DEBUG_STATE_r(                                              \
-        Perl_re_exec_indentf( aTHX_                                         \
-            "Setting an EVAL scope, savestack=%"IVdf",\n",      \
+        Perl_re_exec_indentf( aTHX_                             \
+            "Setting an EVAL scope, savestack=%" IVdf ",\n",    \
             depth, (IV)PL_savestack_ix                          \
         )                                                       \
     );                                                          \
@@ -341,8 +352,9 @@ S_regcppush(pTHX_ const regexp *rex, I32 parenfloor, U32 maxopenparen)
 #define REGCP_UNWIND(cp)                                        \
     DEBUG_STATE_r(                                              \
         if (cp != PL_savestack_ix)                              \
-            Perl_re_exec_indentf( aTHX_                                     \
-                "Clearing an EVAL scope, savestack=%"IVdf"..%"IVdf"\n",\
+            Perl_re_exec_indentf( aTHX_                         \
+                "Clearing an EVAL scope, savestack=%"           \
+                IVdf "..%" IVdf "\n",                           \
                 depth, (IV)(cp), (IV)PL_savestack_ix            \
             )                                                   \
     );                                                          \
@@ -356,7 +368,7 @@ S_regcppush(pTHX_ const regexp *rex, I32 parenfloor, U32 maxopenparen)
 
 
 STATIC void
-S_regcppop(pTHX_ regexp *rex, U32 *maxopenparen_p)
+S_regcppop(pTHX_ regexp *rex, U32 *maxopenparen_p _pDEPTH)
 {
     UV i;
     U32 paren;
@@ -376,9 +388,10 @@ S_regcppop(pTHX_ regexp *rex, U32 *maxopenparen_p)
     /* Now restore the parentheses context. */
     DEBUG_BUFFERS_r(
        if (i || rex->lastparen + 1 <= rex->nparens)
-            Perl_re_printf( aTHX_
-               "rex=0x%"UVxf" offs=0x%"UVxf": restoring capture indices to:\n",
-               PTR2UV(rex),
+            Perl_re_exec_indentf( aTHX_
+               "rex=0x%" UVxf " offs=0x%" UVxf ": restoring capture indices to:\n",
+               depth,
+                PTR2UV(rex),
                PTR2UV(rex->offs)
            );
     );
@@ -390,9 +403,10 @@ S_regcppop(pTHX_ regexp *rex, U32 *maxopenparen_p)
        tmps = SSPOPIV;
        if (paren <= rex->lastparen)
            rex->offs[paren].end = tmps;
-        DEBUG_BUFFERS_r( Perl_re_printf( aTHX_
-           "    \\%"UVuf": %"IVdf"(%"IVdf")..%"IVdf"%s\n",
-           (UV)paren,
+        DEBUG_BUFFERS_r( Perl_re_exec_indentf( aTHX_
+           "    \\%" UVuf ": %" IVdf "(%" IVdf ")..%" IVdf "%s\n",
+           depth,
+            (UV)paren,
            (IV)rex->offs[paren].start,
            (IV)rex->offs[paren].start_tmp,
            (IV)rex->offs[paren].end,
@@ -414,9 +428,10 @@ S_regcppop(pTHX_ regexp *rex, U32 *maxopenparen_p)
        if (i > *maxopenparen_p)
            rex->offs[i].start = -1;
        rex->offs[i].end = -1;
-        DEBUG_BUFFERS_r( Perl_re_printf( aTHX_
-           "    \\%"UVuf": %s   ..-1 undeffing\n",
-           (UV)i,
+        DEBUG_BUFFERS_r( Perl_re_exec_indentf( aTHX_
+           "    \\%" UVuf ": %s   ..-1 undeffing\n",
+           depth,
+            (UV)i,
            (i > *maxopenparen_p) ? "-1" : "  "
        ));
     }
@@ -427,9 +442,11 @@ S_regcppop(pTHX_ regexp *rex, U32 *maxopenparen_p)
  * but without popping the stack */
 
 STATIC void
-S_regcp_restore(pTHX_ regexp *rex, I32 ix, U32 *maxopenparen_p)
+S_regcp_restore(pTHX_ regexp *rex, I32 ix, U32 *maxopenparen_p _pDEPTH)
 {
     I32 tmpix = PL_savestack_ix;
+    PERL_ARGS_ASSERT_REGCP_RESTORE;
+
     PL_savestack_ix = ix;
     regcppop(rex, maxopenparen_p);
     PL_savestack_ix = tmpix;
@@ -437,8 +454,10 @@ S_regcp_restore(pTHX_ regexp *rex, I32 ix, U32 *maxopenparen_p)
 
 #define regcpblow(cp) LEAVE_SCOPE(cp)  /* Ignores regcppush()ed data. */
 
-STATIC bool
-S_isFOO_lc(pTHX_ const U8 classnum, const U8 character)
+#ifndef PERL_IN_XSUB_RE
+
+bool
+Perl_isFOO_lc(pTHX_ const U8 classnum, const U8 character)
 {
     /* Returns a boolean as to whether or not 'character' is a member of the
      * Posix character class given by 'classnum' that should be equivalent to a
@@ -458,7 +477,7 @@ S_isFOO_lc(pTHX_ const U8 classnum, const U8 character)
         case _CC_ENUM_ALPHA:     return isALPHA_LC(character);
         case _CC_ENUM_ASCII:     return isASCII_LC(character);
         case _CC_ENUM_BLANK:     return isBLANK_LC(character);
-        case _CC_ENUM_CASED:     return isLOWER_LC(character)
+        case _CC_ENUM_CASED:     return    isLOWER_LC(character)
                                         || isUPPER_LC(character);
         case _CC_ENUM_CNTRL:     return isCNTRL_LC(character);
         case _CC_ENUM_DIGIT:     return isDIGIT_LC(character);
@@ -478,6 +497,8 @@ S_isFOO_lc(pTHX_ const U8 classnum, const U8 character)
     return FALSE;
 }
 
+#endif
+
 STATIC bool
 S_isFOO_utf8_lc(pTHX_ const U8 classnum, const U8* character)
 {
@@ -531,6 +552,116 @@ S_isFOO_utf8_lc(pTHX_ const U8 classnum, const U8* character)
     return FALSE; /* Things like CNTRL are always below 256 */
 }
 
+STATIC char *
+S_find_next_ascii(char * s, const char * send, const bool utf8_target)
+{
+    /* Returns the position of the first ASCII byte in the sequence between 's'
+     * and 'send-1' inclusive; returns 'send' if none found */
+
+    PERL_ARGS_ASSERT_FIND_NEXT_ASCII;
+
+#ifndef EBCDIC
+
+    if ((STRLEN) (send - s) >= PERL_WORDSIZE
+
+                            /* This term is wordsize if subword; 0 if not */
+                          + PERL_WORDSIZE * PERL_IS_SUBWORD_ADDR(s)
+
+                            /* 'offset' */
+                          - (PTR2nat(s) & PERL_WORD_BOUNDARY_MASK))
+    {
+
+        /* Process per-byte until reach word boundary.  XXX This loop could be
+         * eliminated if we knew that this platform had fast unaligned reads */
+        while (PTR2nat(s) & PERL_WORD_BOUNDARY_MASK) {
+            if (isASCII(*s)) {
+                return s;
+            }
+            s++;    /* khw didn't bother creating a separate loop for
+                       utf8_target */
+        }
+
+        /* Here, we know we have at least one full word to process.  Process
+         * per-word as long as we have at least a full word left */
+        do {
+            if ((* (PERL_UINTMAX_T *) s) & ~ PERL_VARIANTS_WORD_MASK)  {
+                break;
+            }
+            s += PERL_WORDSIZE;
+        } while (s + PERL_WORDSIZE <= send);
+    }
+
+#endif
+
+    /* Process per-character */
+    if (utf8_target) {
+        while (s < send) {
+            if (isASCII(*s)) {
+                return s;
+            }
+            s += UTF8SKIP(s);
+        }
+    }
+    else {
+        while (s < send) {
+            if (isASCII(*s)) {
+                return s;
+            }
+            s++;
+        }
+    }
+
+    return s;
+}
+
+STATIC char *
+S_find_next_non_ascii(char * s, const char * send, const bool utf8_target)
+{
+    /* Returns the position of the first non-ASCII byte in the sequence between
+     * 's' and 'send-1' inclusive; returns 'send' if none found */
+
+#ifdef EBCDIC
+
+    PERL_ARGS_ASSERT_FIND_NEXT_NON_ASCII;
+
+    if (utf8_target) {
+        while (s < send) {
+            if ( ! isASCII(*s)) {
+                return s;
+            }
+            s += UTF8SKIP(s);
+        }
+    }
+    else {
+        while (s < send) {
+            if ( ! isASCII(*s)) {
+                return s;
+            }
+            s++;
+        }
+    }
+
+    return s;
+
+#else
+
+    const U8 * next_non_ascii = NULL;
+
+    PERL_ARGS_ASSERT_FIND_NEXT_NON_ASCII;
+    PERL_UNUSED_ARG(utf8_target);
+
+    /* On ASCII platforms invariants and ASCII are identical, so if the string
+     * is entirely invariants, there is no non-ASCII character */
+    return (is_utf8_invariant_string_loc((U8 *) s,
+                                         (STRLEN) (send - s),
+                                         &next_non_ascii))
+            ? (char *) send
+            : (char *) next_non_ascii;
+
+#endif
+
+}
+
 /*
  * pregexec and friends
  */
@@ -692,7 +823,7 @@ Perl_re_intuit_start(pTHX_
        goto fail;
     }
 
-    RX_MATCH_UTF8_set(rx,utf8_target);
+    RXp_MATCH_UTF8_set(prog, utf8_target);
     reginfo->is_utf8_target = cBOOL(utf8_target);
     reginfo->info_aux = NULL;
     reginfo->strbeg = strbeg;
@@ -703,7 +834,8 @@ Perl_re_intuit_start(pTHX_
     reginfo->poscache_maxiter = 0;
 
     if (utf8_target) {
-       if (!prog->check_utf8 && prog->check_substr)
+        if ((!prog->anchored_utf8 && prog->anchored_substr)
+                || (!prog->float_utf8 && prog->float_substr))
            to_utf8_substr(prog);
        check = prog->check_utf8;
     } else {
@@ -725,8 +857,8 @@ Perl_re_intuit_start(pTHX_
                 continue;
 
             Perl_re_printf( aTHX_
-                "  substrs[%d]: min=%"IVdf" max=%"IVdf" end shift=%"IVdf
-                " useful=%"IVdf" utf8=%d [%s]\n",
+                "  substrs[%d]: min=%" IVdf " max=%" IVdf " end shift=%" IVdf
+                " useful=%" IVdf " utf8=%d [%s]\n",
                 i,
                 (IV)prog->substrs->data[i].min_offset,
                 (IV)prog->substrs->data[i].max_offset,
@@ -785,7 +917,7 @@ Perl_re_intuit_start(pTHX_
                 char *s = HOP3c(strpos, prog->check_offset_min, strend);
            
                 DEBUG_EXECUTE_r(Perl_re_printf( aTHX_
-                    "  Looking for check substr at fixed offset %"IVdf"...\n",
+                    "  Looking for check substr at fixed offset %" IVdf "...\n",
                     (IV)prog->check_offset_min));
 
                if (SvTAIL(check)) {
@@ -805,8 +937,9 @@ Perl_re_intuit_start(pTHX_
                     /* Now should match s[0..slen-2] */
                     slen--;
                 }
-                if (slen && (*SvPVX_const(check) != *s
-                    || (slen > 1 && memNE(SvPVX_const(check), s, slen))))
+                if (slen && (strend - s < slen
+                    || *SvPVX_const(check) != *s
+                    || (slen > 1 && (memNE(SvPVX_const(check), s, slen)))))
                 {
                     DEBUG_EXECUTE_r(Perl_re_printf( aTHX_
                                     "  String not equal...\n"));
@@ -823,8 +956,8 @@ Perl_re_intuit_start(pTHX_
 
 #ifdef DEBUGGING       /* 7/99: reports of failure (with the older version) */
     if (end_shift < 0)
-       Perl_croak(aTHX_ "panic: end_shift: %"IVdf" pattern:\n%s\n ",
-                  (IV)end_shift, RX_PRECOMP(prog));
+       Perl_croak(aTHX_ "panic: end_shift: %" IVdf " pattern:\n%s\n ",
+                  (IV)end_shift, RX_PRECOMP(rx));
 #endif
 
   restart:
@@ -860,9 +993,9 @@ Perl_re_intuit_start(pTHX_
 
         DEBUG_OPTIMISE_MORE_r({
             Perl_re_printf( aTHX_
-                "  At restart: rx_origin=%"IVdf" Check offset min: %"IVdf
-                " Start shift: %"IVdf" End shift %"IVdf
-                " Real end Shift: %"IVdf"\n",
+                "  At restart: rx_origin=%" IVdf " Check offset min: %" IVdf
+                " Start shift: %" IVdf " End shift %" IVdf
+                " Real end Shift: %" IVdf "\n",
                 (IV)(rx_origin - strbeg),
                 (IV)prog->check_offset_min,
                 (IV)start_shift,
@@ -870,7 +1003,9 @@ Perl_re_intuit_start(pTHX_
                 (IV)prog->check_end_shift);
         });
         
-        end_point = HOP3(strend, -end_shift, strbeg);
+        end_point = HOPBACK3(strend, end_shift, rx_origin);
+        if (!end_point)
+            goto fail_finish;
         start_point = HOPMAYBE3(rx_origin, start_shift, end_point);
         if (!start_point)
             goto fail_finish;
@@ -888,19 +1023,28 @@ Perl_re_intuit_start(pTHX_
             && prog->intflags & PREGf_ANCH
             && prog->check_offset_max != SSize_t_MAX)
         {
-            SSize_t len = SvCUR(check) - !!SvTAIL(check);
+            SSize_t check_len = SvCUR(check) - !!SvTAIL(check);
             const char * const anchor =
                         (prog->intflags & PREGf_ANCH_GPOS ? strpos : strbeg);
+            SSize_t targ_len = (char*)end_point - anchor;
+
+            if (check_len > targ_len) {
+                DEBUG_EXECUTE_r(Perl_re_printf( aTHX_
+                             "Anchored string too short...\n"));
+                goto fail_finish;
+            }
 
             /* do a bytes rather than chars comparison. It's conservative;
              * so it skips doing the HOP if the result can't possibly end
              * up earlier than the old value of end_point.
              */
-            if ((char*)end_point - anchor > prog->check_offset_max) {
+            assert(anchor + check_len <= (char *)end_point);
+            if (prog->check_offset_max + check_len < targ_len) {
                 end_point = HOP3lim((U8*)anchor,
                                 prog->check_offset_max,
-                                end_point -len)
-                            + len;
+                                end_point - check_len
+                            )
+                            + check_len;
             }
         }
 
@@ -908,7 +1052,7 @@ Perl_re_intuit_start(pTHX_
                      check, multiline ? FBMrf_MULTILINE : 0);
 
         DEBUG_EXECUTE_r(Perl_re_printf( aTHX_
-            "  doing 'check' fbm scan, [%"IVdf"..%"IVdf"] gave %"IVdf"\n",
+            "  doing 'check' fbm scan, [%" IVdf "..%" IVdf "] gave %" IVdf "\n",
             (IV)((char*)start_point - strbeg),
             (IV)((char*)end_point   - strbeg),
             (IV)(check_at ? check_at - strbeg : -1)
@@ -940,7 +1084,7 @@ Perl_re_intuit_start(pTHX_
             rx_origin = HOP3c(check_at, -prog->check_offset_max, rx_origin);
         /* Finish the diagnostic message */
         DEBUG_EXECUTE_r(Perl_re_printf( aTHX_
-            "%ld (rx_origin now %"IVdf")...\n",
+            "%ld (rx_origin now %" IVdf ")...\n",
             (long)(check_at - strbeg),
             (IV)(rx_origin - strbeg)
         ));
@@ -1051,10 +1195,12 @@ Perl_re_intuit_start(pTHX_
             char *from = s;
             char *to   = last + SvCUR(must) - (SvTAIL(must)!=0);
 
+            if (to > strend)
+                to = strend;
             if (from > to) {
                 s = NULL;
                 DEBUG_EXECUTE_r(Perl_re_printf( aTHX_
-                    "  skipping 'other' fbm scan: %"IVdf" > %"IVdf"\n",
+                    "  skipping 'other' fbm scan: %" IVdf " > %" IVdf "\n",
                     (IV)(from - strbeg),
                     (IV)(to   - strbeg)
                 ));
@@ -1067,7 +1213,7 @@ Perl_re_intuit_start(pTHX_
                     multiline ? FBMrf_MULTILINE : 0
                 );
                 DEBUG_EXECUTE_r(Perl_re_printf( aTHX_
-                    "  doing 'other' fbm scan, [%"IVdf"..%"IVdf"] gave %"IVdf"\n",
+                    "  doing 'other' fbm scan, [%" IVdf "..%" IVdf "] gave %" IVdf "\n",
                     (IV)(from - strbeg),
                     (IV)(to   - strbeg),
                     (IV)(s ? s - strbeg : -1)
@@ -1103,7 +1249,7 @@ Perl_re_intuit_start(pTHX_
                     ? HOP3c(rx_origin, 1, strend)
                     : HOP4c(last, 1 - other->min_offset, strbeg, strend);
             DEBUG_EXECUTE_r(Perl_re_printf( aTHX_
-                "; about to retry %s at offset %ld (rx_origin now %"IVdf")...\n",
+                "; about to retry %s at offset %ld (rx_origin now %" IVdf ")...\n",
                 (other_ix ? "floating" : "anchored"),
                 (long)(HOP3c(check_at, 1, strend) - strbeg),
                 (IV)(rx_origin - strbeg)
@@ -1127,7 +1273,7 @@ Perl_re_intuit_start(pTHX_
                 other_last = HOP3c(s, 1, strend);
             }
             DEBUG_EXECUTE_r(Perl_re_printf( aTHX_
-                " at offset %ld (rx_origin now %"IVdf")...\n",
+                " at offset %ld (rx_origin now %" IVdf ")...\n",
                   (long)(s - strbeg),
                 (IV)(rx_origin - strbeg)
               ));
@@ -1137,9 +1283,9 @@ Perl_re_intuit_start(pTHX_
     else {
         DEBUG_OPTIMISE_MORE_r(
             Perl_re_printf( aTHX_
-                "  Check-only match: offset min:%"IVdf" max:%"IVdf
-                " check_at:%"IVdf" rx_origin:%"IVdf" rx_origin-check_at:%"IVdf
-                " strend:%"IVdf"\n",
+                "  Check-only match: offset min:%" IVdf " max:%" IVdf
+                " check_at:%" IVdf " rx_origin:%" IVdf " rx_origin-check_at:%" IVdf
+                " strend:%" IVdf "\n",
                 (IV)prog->check_offset_min,
                 (IV)prog->check_offset_max,
                 (IV)(check_at-strbeg),
@@ -1211,7 +1357,7 @@ Perl_re_intuit_start(pTHX_
              * didn't contradict, so just retry the anchored "other"
              * substr */
             DEBUG_EXECUTE_r(Perl_re_printf( aTHX_
-                "  Found /%s^%s/m, rescanning for anchored from offset %"IVdf" (rx_origin now %"IVdf")...\n",
+                "  Found /%s^%s/m, rescanning for anchored from offset %" IVdf " (rx_origin now %" IVdf ")...\n",
                 PL_colors[0], PL_colors[1],
                 (IV)(rx_origin - strbeg + prog->anchored_offset),
                 (IV)(rx_origin - strbeg)
@@ -1276,17 +1422,17 @@ Perl_re_intuit_start(pTHX_
          */
 
        if (prog->anchored_substr || prog->anchored_utf8 || ml_anch)
-            endpos= HOP3c(rx_origin, (prog->minlen ? cl_l : 0), strend);
+            endpos = HOP3clim(rx_origin, (prog->minlen ? cl_l : 0), strend);
         else if (prog->float_substr || prog->float_utf8) {
            rx_max_float = HOP3c(check_at, -start_shift, strbeg);
-           endpos= HOP3c(rx_max_float, cl_l, strend);
+           endpos = HOP3clim(rx_max_float, cl_l, strend);
         }
         else 
             endpos= strend;
                    
         DEBUG_EXECUTE_r(Perl_re_printf( aTHX_
-            "  looking for class: start_shift: %"IVdf" check_at: %"IVdf
-            " rx_origin: %"IVdf" endpos: %"IVdf"\n",
+            "  looking for class: start_shift: %" IVdf " check_at: %" IVdf
+            " rx_origin: %" IVdf " endpos: %" IVdf "\n",
               (IV)start_shift, (IV)(check_at - strbeg),
               (IV)(rx_origin - strbeg), (IV)(endpos - strbeg)));
 
@@ -1320,7 +1466,7 @@ Perl_re_intuit_start(pTHX_
                          * practice the extra fbm_instr() is likely to
                          * get skipped anyway. */
                         DEBUG_EXECUTE_r( Perl_re_printf( aTHX_
-                            "  about to retry anchored at offset %ld (rx_origin now %"IVdf")...\n",
+                            "  about to retry anchored at offset %ld (rx_origin now %" IVdf ")...\n",
                             (long)(other_last - strbeg),
                             (IV)(rx_origin - strbeg)
                         ));
@@ -1369,7 +1515,7 @@ Perl_re_intuit_start(pTHX_
                 goto fail;
             }
             DEBUG_EXECUTE_r( Perl_re_printf( aTHX_
-                "  about to look for %s substr starting at offset %ld (rx_origin now %"IVdf")...\n",
+                "  about to look for %s substr starting at offset %ld (rx_origin now %" IVdf ")...\n",
                 (prog->substrs->check_ix ? "floating" : "anchored"),
                 (long)(rx_origin + start_shift - strbeg),
                 (IV)(rx_origin - strbeg)
@@ -1488,8 +1634,9 @@ STMT_START {
             uscan += len;                                                           \
             len=0;                                                                  \
         } else {                                                                    \
-            uvc = _to_utf8_fold_flags( (const U8*) uc, foldbuf, &foldlen, flags);   \
             len = UTF8SKIP(uc);                                                     \
+            uvc = _toFOLD_utf8_flags( (const U8*) uc, uc + len, foldbuf, &foldlen,  \
+                                                                            flags); \
             skiplen = UVCHR_SKIP( uvc );                                            \
             foldlen -= skiplen;                                                     \
             uscan = foldbuf + skiplen;                                              \
@@ -1666,7 +1813,7 @@ REXEC_FBC_SCAN( /* Loops while (s < strend) */                 \
     tmp = TEST_UV(tmp);                                                        \
     LOAD_UTF8_CHARCLASS_ALNUM();                                               \
     REXEC_FBC_UTF8_SCAN( /* advances s while s < strend */                     \
-        if (tmp == ! (TEST_UTF8((U8 *) s))) {                                  \
+        if (tmp == ! (TEST_UTF8((U8 *) s, (U8 *) reginfo->strend))) {          \
             tmp = !tmp;                                                        \
             IF_SUCCESS;                                                        \
         }                                                                      \
@@ -1869,8 +2016,11 @@ S_find_byclass(pTHX_ regexp * prog, const regnode *c, char *s,
             REXEC_FBC_UTF8_CLASS_SCAN(
                       reginclass(prog, c, (U8*)s, (U8*) strend, utf8_target));
         }
+        else if (ANYOF_FLAGS(c)) {
+            REXEC_FBC_CLASS_SCAN(reginclass(prog,c, (U8*)s, (U8*)s+1, 0));
+        }
         else {
-            REXEC_FBC_CLASS_SCAN(REGINCLASS(prog, c, (U8*)s, 0));
+            REXEC_FBC_CLASS_SCAN(ANYOF_BITMAP_TEST(c, *((U8*)s)));
         }
         break;
 
@@ -1954,10 +2104,8 @@ S_find_byclass(pTHX_ regexp * prog, const regnode *c, char *s,
          * trying that it will fail; so don't start a match past the
          * required minimum number from the far end */
         e = HOP3c(strend, -((SSize_t)ln), s);
-
-        if (reginfo->intuit && e < s) {
-            e = s;                     /* Due to minlen logic of intuit() */
-        }
+        if (e < s)
+            break;
 
         c1 = *pat_string;
         c2 = fold_array[c1];
@@ -2001,10 +2149,6 @@ S_find_byclass(pTHX_ regexp * prog, const regnode *c, char *s,
          */
         e = HOP3c(strend, -((SSize_t)lnc), s);
 
-        if (reginfo->intuit && e < s) {
-            e = s;                     /* Due to minlen logic of intuit() */
-        }
-
         /* XXX Note that we could recalculate e to stop the loop earlier,
          * as the worst case expansion above will rarely be met, and as we
          * go along we would usually find that e moves further to the left.
@@ -2035,7 +2179,7 @@ S_find_byclass(pTHX_ regexp * prog, const regnode *c, char *s,
             goto do_boundu;
         }
 
-        FBC_BOUND(isWORDCHAR_LC, isWORDCHAR_LC_uvchr, isWORDCHAR_LC_utf8);
+        FBC_BOUND(isWORDCHAR_LC, isWORDCHAR_LC_uvchr, isWORDCHAR_LC_utf8_safe);
         break;
 
     case NBOUNDL:
@@ -2048,14 +2192,14 @@ S_find_byclass(pTHX_ regexp * prog, const regnode *c, char *s,
             goto do_nboundu;
         }
 
-        FBC_NBOUND(isWORDCHAR_LC, isWORDCHAR_LC_uvchr, isWORDCHAR_LC_utf8);
+        FBC_NBOUND(isWORDCHAR_LC, isWORDCHAR_LC_uvchr, isWORDCHAR_LC_utf8_safe);
         break;
 
     case BOUND: /* regcomp.c makes sure that this only has the traditional \b
                    meaning */
         assert(FLAGS(c) == TRADITIONAL_BOUND);
 
-        FBC_BOUND(isWORDCHAR, isWORDCHAR_uni, isWORDCHAR_utf8);
+        FBC_BOUND(isWORDCHAR, isWORDCHAR_uni, isWORDCHAR_utf8_safe);
         break;
 
     case BOUNDA: /* regcomp.c makes sure that this only has the traditional \b
@@ -2069,7 +2213,7 @@ S_find_byclass(pTHX_ regexp * prog, const regnode *c, char *s,
                    meaning */
         assert(FLAGS(c) == TRADITIONAL_BOUND);
 
-        FBC_NBOUND(isWORDCHAR, isWORDCHAR_uni, isWORDCHAR_utf8);
+        FBC_NBOUND(isWORDCHAR, isWORDCHAR_uni, isWORDCHAR_utf8_safe);
         break;
 
     case NBOUNDA: /* regcomp.c makes sure that this only has the traditional \b
@@ -2081,7 +2225,7 @@ S_find_byclass(pTHX_ regexp * prog, const regnode *c, char *s,
 
     case NBOUNDU:
         if ((bound_type) FLAGS(c) == TRADITIONAL_BOUND) {
-            FBC_NBOUND(isWORDCHAR_L1, isWORDCHAR_uni, isWORDCHAR_utf8);
+            FBC_NBOUND(isWORDCHAR_L1, isWORDCHAR_uni, isWORDCHAR_utf8_safe);
             break;
         }
 
@@ -2094,7 +2238,7 @@ S_find_byclass(pTHX_ regexp * prog, const regnode *c, char *s,
       do_boundu:
         switch((bound_type) FLAGS(c)) {
             case TRADITIONAL_BOUND:
-                FBC_BOUND(isWORDCHAR_L1, isWORDCHAR_uni, isWORDCHAR_utf8);
+                FBC_BOUND(isWORDCHAR_L1, isWORDCHAR_uni, isWORDCHAR_utf8_safe);
                 break;
             case GCB_BOUND:
                 if (s == reginfo->strbeg) {
@@ -2118,7 +2262,11 @@ S_find_byclass(pTHX_ regexp * prog, const regnode *c, char *s,
                     while (s < strend) {
                         GCB_enum after = getGCB_VAL_UTF8((U8*) s,
                                                         (U8*) reginfo->strend);
-                        if (   (to_complement ^ isGCB(before, after))
+                        if (   (to_complement ^ isGCB(before,
+                                                      after,
+                                                      (U8*) reginfo->strbeg,
+                                                      (U8*) s,
+                                                      utf8_target))
                             && (reginfo->intuit || regtry(reginfo, &s)))
                         {
                             goto got_it;
@@ -2341,6 +2489,22 @@ S_find_byclass(pTHX_ regexp * prog, const regnode *c, char *s,
         );
         break;
 
+    case ASCII:
+        s = find_next_ascii(s, strend, utf8_target);
+        if (s < strend && (reginfo->intuit || regtry(reginfo, &s))) {
+            goto got_it;
+        }
+
+        break;
+
+    case NASCII:
+        s = find_next_non_ascii(s, strend, utf8_target);
+        if (s < strend && (reginfo->intuit || regtry(reginfo, &s))) {
+            goto got_it;
+        }
+
+        break;
+
     /* The argument to all the POSIX node types is the class number to pass to
      * _generic_isCC() to build a mask for searching in PL_charclass[] */
 
@@ -2368,18 +2532,25 @@ S_find_byclass(pTHX_ regexp * prog, const regnode *c, char *s,
         if (utf8_target) {
             /* The complement of something that matches only ASCII matches all
              * non-ASCII, plus everything in ASCII that isn't in the class. */
-            REXEC_FBC_UTF8_CLASS_SCAN(! isASCII_utf8(s)
+            REXEC_FBC_UTF8_CLASS_SCAN(   ! isASCII_utf8_safe(s, strend)
                                       || ! _generic_isCC_A(*s, FLAGS(c)));
             break;
         }
 
         to_complement = 1;
-        /* FALLTHROUGH */
+        goto posixa;
 
     case POSIXA:
-      posixa:
         /* Don't need to worry about utf8, as it can match only a single
-         * byte invariant character. */
+         * byte invariant character.  But we do anyway for performance reasons,
+         * as otherwise we would have to examine all the continuation
+         * characters */
+        if (utf8_target) {
+            REXEC_FBC_UTF8_CLASS_SCAN(_generic_isCC_A(*s, FLAGS(c)));
+            break;
+        }
+
+      posixa:
         REXEC_FBC_CLASS_SCAN(
                         to_complement ^ cBOOL(_generic_isCC_A(*s, FLAGS(c))));
         break;
@@ -2410,7 +2581,7 @@ S_find_byclass(pTHX_ regexp * prog, const regnode *c, char *s,
                     if ((UTF8_IS_INVARIANT(*s)
                          && to_complement ^ cBOOL(_generic_isCC((U8) *s,
                                                                 classnum)))
-                        || (UTF8_IS_DOWNGRADEABLE_START(*s)
+                        || (   UTF8_IS_NEXT_CHAR_DOWNGRADEABLE(s, strend)
                             && to_complement ^ cBOOL(
                                 _generic_isCC(EIGHT_BIT_UTF8_TO_NATIVE(*s,
                                                                       *(s + 1)),
@@ -2432,27 +2603,27 @@ S_find_byclass(pTHX_ regexp * prog, const regnode *c, char *s,
                                            macros */
                 case _CC_ENUM_SPACE:
                     REXEC_FBC_UTF8_CLASS_SCAN(
-                                        to_complement ^ cBOOL(isSPACE_utf8(s)));
+                        to_complement ^ cBOOL(isSPACE_utf8_safe(s, strend)));
                     break;
 
                 case _CC_ENUM_BLANK:
                     REXEC_FBC_UTF8_CLASS_SCAN(
-                                        to_complement ^ cBOOL(isBLANK_utf8(s)));
+                        to_complement ^ cBOOL(isBLANK_utf8_safe(s, strend)));
                     break;
 
                 case _CC_ENUM_XDIGIT:
                     REXEC_FBC_UTF8_CLASS_SCAN(
-                                       to_complement ^ cBOOL(isXDIGIT_utf8(s)));
+                       to_complement ^ cBOOL(isXDIGIT_utf8_safe(s, strend)));
                     break;
 
                 case _CC_ENUM_VERTSPACE:
                     REXEC_FBC_UTF8_CLASS_SCAN(
-                                       to_complement ^ cBOOL(isVERTWS_utf8(s)));
+                       to_complement ^ cBOOL(isVERTWS_utf8_safe(s, strend)));
                     break;
 
                 case _CC_ENUM_CNTRL:
                     REXEC_FBC_UTF8_CLASS_SCAN(
-                                        to_complement ^ cBOOL(isCNTRL_utf8(s)));
+                        to_complement ^ cBOOL(isCNTRL_utf8_safe(s, strend)));
                     break;
 
                 default:
@@ -2477,9 +2648,10 @@ S_find_byclass(pTHX_ regexp * prog, const regnode *c, char *s,
          * FBC macro instead of being expanded out.  Since we've loaded the
          * swash, we don't have to check for that each time through the loop */
         REXEC_FBC_UTF8_CLASS_SCAN(
-                to_complement ^ cBOOL(_generic_utf8(
+                to_complement ^ cBOOL(_generic_utf8_safe(
                                       classnum,
                                       s,
+                                      strend,
                                       swash_fetch(PL_utf8_swash_ptrs[classnum],
                                                   (U8 *) s, TRUE))));
         break;
@@ -2607,7 +2779,7 @@ S_find_byclass(pTHX_ regexp * prog, const regnode *c, char *s,
                             dump_exec_pos( (char *)uc, c, strend,
                                         real_start, s, utf8_target, 0);
                             Perl_re_printf( aTHX_
-                                " Charid:%3u CP:%4"UVxf" ",
+                                " Charid:%3u CP:%4" UVxf " ",
                                  charid, uvc);
                         });
                     }
@@ -2628,7 +2800,7 @@ S_find_byclass(pTHX_ regexp * prog, const regnode *c, char *s,
                                 dump_exec_pos( (char *)uc, c, strend, real_start,
                                     s,   utf8_target, 0 );
                             Perl_re_printf( aTHX_
-                                "%sState: %4"UVxf", word=%"UVxf,
+                                "%sState: %4" UVxf ", word=%" UVxf,
                                 failed ? " Fail transition to " : "",
                                 (UV)state, (UV)word);
                         });
@@ -2679,7 +2851,7 @@ S_find_byclass(pTHX_ regexp * prog, const regnode *c, char *s,
                 if (leftmost) {
                     s = (char*)leftmost;
                     DEBUG_TRIE_EXECUTE_r({
-                        Perl_re_printf( aTHX_  "Matches word #%"UVxf" at position %"IVdf". Trying full pattern...\n",
+                        Perl_re_printf( aTHX_  "Matches word #%" UVxf " at position %" IVdf ". Trying full pattern...\n",
                             (UV)accepted_word, (IV)(s - real_start)
                         );
                     });
@@ -2747,7 +2919,7 @@ S_reg_set_capture_string(pTHX_ REGEXP * const rx,
             }
             else {
                 /* create new COW SV to share string */
-                RX_MATCH_COPY_FREE(rx);
+                RXp_MATCH_COPY_FREE(prog);
                 prog->saved_copy = sv_setsv_cow(prog->saved_copy, sv);
             }
             prog->subbeg = (char *)SvPVX_const(prog->saved_copy);
@@ -2810,7 +2982,7 @@ S_reg_set_capture_string(pTHX_ REGEXP * const rx,
             assert(min >= 0 && min <= max && min <= strend - strbeg);
             sublen = max - min;
 
-            if (RX_MATCH_COPIED(rx)) {
+            if (RXp_MATCH_COPIED(prog)) {
                 if (sublen > prog->sublen)
                     prog->subbeg =
                             (char*)saferealloc(prog->subbeg, sublen+1);
@@ -2821,7 +2993,7 @@ S_reg_set_capture_string(pTHX_ REGEXP * const rx,
             prog->subbeg[sublen] = '\0';
             prog->suboffset = min;
             prog->sublen = sublen;
-            RX_MATCH_COPIED_on(rx);
+            RXp_MATCH_COPIED_on(prog);
         }
         prog->subcoffset = prog->suboffset;
         if (prog->suboffset && utf8_target) {
@@ -2848,7 +3020,7 @@ S_reg_set_capture_string(pTHX_ REGEXP * const rx,
         }
     }
     else {
-        RX_MATCH_COPY_FREE(rx);
+        RXp_MATCH_COPY_FREE(prog);
         prog->subbeg = strbeg;
         prog->suboffset = 0;
         prog->subcoffset = 0;
@@ -2925,7 +3097,7 @@ Perl_regexec_flags(pTHX_ REGEXP * const rx, char *stringarg, char *strend,
             : strbeg; /* pos() not defined; use start of string */
 
         DEBUG_GPOS_r(Perl_re_printf( aTHX_
-            "GPOS ganch set to strbeg[%"IVdf"]\n", (IV)(reginfo->ganch - strbeg)));
+            "GPOS ganch set to strbeg[%" IVdf "]\n", (IV)(reginfo->ganch - strbeg)));
 
         /* in the presence of \G, we may need to start looking earlier in
          * the string than the suggested start point of stringarg:
@@ -3005,7 +3177,7 @@ Perl_regexec_flags(pTHX_ REGEXP * const rx, char *stringarg, char *strend,
             /* match via INTUIT shouldn't have any captures.
              * Let @-, @+, $^N know */
             prog->lastparen = prog->lastcloseparen = 0;
-            RX_MATCH_UTF8_set(rx, utf8_target);
+            RXp_MATCH_UTF8_set(prog, utf8_target);
             prog->offs[0].start = s - strbeg;
             prog->offs[0].end = utf8_target
                 ? (char*)utf8_hop((U8*)s, prog->minlenret) - strbeg
@@ -3032,8 +3204,8 @@ Perl_regexec_flags(pTHX_ REGEXP * const rx, char *stringarg, char *strend,
        Perl_croak(aTHX_ "corrupted regexp program");
     }
 
-    RX_MATCH_TAINTED_off(rx);
-    RX_MATCH_UTF8_set(rx, utf8_target);
+    RXp_MATCH_TAINTED_off(prog);
+    RXp_MATCH_UTF8_set(prog, utf8_target);
 
     reginfo->prog = rx;         /* Yes, sorry that this is confusing.  */
     reginfo->intuit = 0;
@@ -3119,9 +3291,10 @@ Perl_regexec_flags(pTHX_ REGEXP * const rx, char *stringarg, char *strend,
         swap = prog->offs;
         /* do we need a save destructor here for eval dies? */
         Newxz(prog->offs, (prog->nparens + 1), regexp_paren_pair);
-        DEBUG_BUFFERS_r(Perl_re_printf( aTHX_
-           "rex=0x%"UVxf" saving  offs: orig=0x%"UVxf" new=0x%"UVxf"\n",
-           PTR2UV(prog),
+        DEBUG_BUFFERS_r(Perl_re_exec_indentf( aTHX_
+           "rex=0x%" UVxf " saving  offs: orig=0x%" UVxf " new=0x%" UVxf "\n",
+           0,
+            PTR2UV(prog),
            PTR2UV(swap),
            PTR2UV(prog->offs)
        ));
@@ -3354,7 +3527,7 @@ Perl_regexec_flags(pTHX_ REGEXP * const rx, char *stringarg, char *strend,
             regprop(prog, prop, c, reginfo, NULL);
            {
                RE_PV_QUOTED_DECL(quoted,utf8_target,PERL_DEBUG_PAD_ZERO(1),
-                   s,strend-s,60);
+                   s,strend-s,PL_dump_re_max_len);
                 Perl_re_printf( aTHX_
                    "Matching stclass %.*s against %s (%d bytes)\n",
                    (int)SvCUR(prop), SvPVX_const(prop),
@@ -3503,9 +3676,10 @@ Perl_regexec_flags(pTHX_ REGEXP * const rx, char *stringarg, char *strend,
 
     DEBUG_BUFFERS_r(
        if (swap)
-            Perl_re_printf( aTHX_
-               "rex=0x%"UVxf" freeing offs: 0x%"UVxf"\n",
-               PTR2UV(prog),
+            Perl_re_exec_indentf( aTHX_
+               "rex=0x%" UVxf " freeing offs: 0x%" UVxf "\n",
+               0,
+                PTR2UV(prog),
                PTR2UV(swap)
            );
     );
@@ -3540,9 +3714,10 @@ Perl_regexec_flags(pTHX_ REGEXP * const rx, char *stringarg, char *strend,
 
     if (swap) {
         /* we failed :-( roll it back */
-        DEBUG_BUFFERS_r(Perl_re_printf( aTHX_
-           "rex=0x%"UVxf" rolling back offs: freeing=0x%"UVxf" restoring=0x%"UVxf"\n",
-           PTR2UV(prog),
+        DEBUG_BUFFERS_r(Perl_re_exec_indentf( aTHX_
+           "rex=0x%" UVxf " rolling back offs: freeing=0x%" UVxf " restoring=0x%" UVxf "\n",
+           0,
+            PTR2UV(prog),
            PTR2UV(prog->offs),
            PTR2UV(swap)
        ));
@@ -3600,6 +3775,14 @@ S_regtry(pTHX_ regmatch_info *reginfo, char **startposp)
      * above-mentioned test suite tests to succeed.  The common theme
      * on those tests seems to be returning null fields from matches.
      * --jhi updated by dapm */
+
+    /* After encountering a variant of the issue mentioned above I think
+     * the point Ilya was making is that if we properly unwind whenever
+     * we set lastparen to a smaller value then we should not need to do
+     * this every time, only when needed. So if we have tests that fail if
+     * we remove this, then it suggests somewhere else we are improperly
+     * unwinding the lastparen/paren buffers. See UNWIND_PARENS() and
+     * places it is called, and related regcp() routines. - Yves */
 #if 1
     if (prog->nparens) {
        regexp_paren_pair *pp = prog->offs;
@@ -3640,7 +3823,7 @@ S_regtry(pTHX_ regmatch_info *reginfo, char **startposp)
    messages are inline with the regop output that created them.
 */
 #define REPORT_CODE_OFF 29
-#define INDENT_CHARS(depth) ((depth) % 20)
+#define INDENT_CHARS(depth) ((int)(depth) % 20)
 #ifdef DEBUGGING
 int
 Perl_re_exec_indentf(pTHX_ const char *fmt, U32 depth, ...)
@@ -3650,7 +3833,7 @@ Perl_re_exec_indentf(pTHX_ const char *fmt, U32 depth, ...)
     PerlIO *f= Perl_debug_log;
     PERL_ARGS_ASSERT_RE_EXEC_INDENTF;
     va_start(ap, depth);
-    PerlIO_printf(f, "%*s|%4d| %*s", REPORT_CODE_OFF, "", depth, INDENT_CHARS(depth), "" );
+    PerlIO_printf(f, "%*s|%4" UVuf "| %*s", REPORT_CODE_OFF, "", (UV)depth, INDENT_CHARS(depth), "" );
     result = PerlIO_vprintf(f, fmt, ap);
     va_end(ap);
     return result;
@@ -3668,9 +3851,6 @@ Perl_re_exec_indentf(pTHX_ const char *fmt, U32 depth, ...)
 STATIC regmatch_state *
 S_push_slab(pTHX)
 {
-#if PERL_VERSION < 9 && !defined(PERL_CORE)
-    dMY_CXT;
-#endif
     regmatch_slab *s = PL_regmatch_slab->next;
     if (!s) {
        Newx(s, 1, regmatch_slab);
@@ -3867,10 +4047,10 @@ S_debug_start_match(pTHX_ const REGEXP *prog, const bool utf8_target,
             reginitcolors();    
     {
         RE_PV_QUOTED_DECL(s0, utf8_pat, PERL_DEBUG_PAD_ZERO(0), 
-            RX_PRECOMP_const(prog), RX_PRELEN(prog), 60);   
+            RX_PRECOMP_const(prog), RX_PRELEN(prog), PL_dump_re_max_len);
         
         RE_PV_QUOTED_DECL(s1, utf8_target, PERL_DEBUG_PAD_ZERO(1),
-            start, end - start, 60); 
+            start, end - start, PL_dump_re_max_len);
         
         Perl_re_printf( aTHX_
             "%s%s REx%s %s against %s\n", 
@@ -3926,18 +4106,18 @@ S_dump_exec_pos(pTHX_ const char *locinput,
        const int is_uni = utf8_target ? 1 : 0;
 
        RE_PV_COLOR_DECL(s0,len0,is_uni,PERL_DEBUG_PAD(0),
-           (locinput - pref_len),pref0_len, 60, 4, 5);
+           (locinput - pref_len),pref0_len, PL_dump_re_max_len, 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);
+                   pref_len - pref0_len, PL_dump_re_max_len, 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;
         Perl_re_printf( aTHX_
-                    "%4"IVdf" <%.*s%.*s%s%.*s>%*s|%4u| ",
+                    "%4" IVdf " <%.*s%.*s%s%.*s>%*s|%4u| ",
                    (IV)(locinput - loc_bostr),
                    len0, s0,
                    len1, s1,
@@ -4105,10 +4285,11 @@ S_setup_EXACTISH_ST_c1_c2(pTHX_ const regnode * const text_node, int *c1p,
                     }
                     else {
                         STRLEN len;
-                        _to_utf8_fold_flags(s,
-                                            d,
-                                            &len,
-                                            FOLD_FLAGS_FULL | FOLD_FLAGS_LOCALE);
+                        _toFOLD_utf8_flags(s,
+                                           pat_end,
+                                           d,
+                                           &len,
+                                           FOLD_FLAGS_FULL | FOLD_FLAGS_LOCALE);
                         d += len;
                         s += UTF8SKIP(s);
                     }
@@ -4153,7 +4334,7 @@ S_setup_EXACTISH_ST_c1_c2(pTHX_ const regnode * const text_node, int *c1p,
                 }
                 else {  /* Does participate in folds */
                     AV* list = (AV*) *listp;
-                    if (av_tindex_nomg(list) != 1) {
+                    if (av_tindex_skip_len_mg(list) != 1) {
 
                         /* If there aren't exactly two folds to this, it is
                          * outside the scope of this function */
@@ -4289,13 +4470,108 @@ S_setup_EXACTISH_ST_c1_c2(pTHX_ const regnode * const text_node, int *c1p,
     return TRUE;
 }
 
-PERL_STATIC_INLINE bool
-S_isGCB(const GCB_enum before, const GCB_enum after)
+STATIC bool
+S_isGCB(pTHX_ const GCB_enum before, const GCB_enum after, const U8 * const strbeg, const U8 * const curpos, const bool utf8_target)
 {
     /* returns a boolean indicating if there is a Grapheme Cluster Boundary
-     * between the inputs.  See http://www.unicode.org/reports/tr29/ */
+     * between the inputs.  See http://www.unicode.org/reports/tr29/. */
+
+    PERL_ARGS_ASSERT_ISGCB;
+
+    switch (GCB_table[before][after]) {
+        case GCB_BREAKABLE:
+            return TRUE;
+
+        case GCB_NOBREAK:
+            return FALSE;
+
+        case GCB_RI_then_RI:
+            {
+                int RI_count = 1;
+                U8 * temp_pos = (U8 *) curpos;
+
+                /* Do not break within emoji flag sequences. That is, do not
+                 * break between regional indicator (RI) symbols if there is an
+                 * odd number of RI characters before the break point.
+                 *  GB12   sot (RI RI)* RI × RI
+                 *  GB13 [^RI] (RI RI)* RI × RI */
+
+                while (backup_one_GCB(strbeg,
+                                    &temp_pos,
+                                    utf8_target) == GCB_Regional_Indicator)
+                {
+                    RI_count++;
+                }
+
+                return RI_count % 2 != 1;
+            }
+
+        case GCB_EX_then_EM:
+
+            /* GB10  ( E_Base | E_Base_GAZ ) Extend* ×  E_Modifier */
+            {
+                U8 * temp_pos = (U8 *) curpos;
+                GCB_enum prev;
+
+                do {
+                    prev = backup_one_GCB(strbeg, &temp_pos, utf8_target);
+                }
+                while (prev == GCB_Extend);
+
+                return prev != GCB_E_Base && prev != GCB_E_Base_GAZ;
+            }
+
+        default:
+            break;
+    }
+
+#ifdef DEBUGGING
+    Perl_re_printf( aTHX_  "Unhandled GCB pair: GCB_table[%d, %d] = %d\n",
+                                  before, after, GCB_table[before][after]);
+    assert(0);
+#endif
+    return TRUE;
+}
+
+STATIC GCB_enum
+S_backup_one_GCB(pTHX_ const U8 * const strbeg, U8 ** curpos, const bool utf8_target)
+{
+    GCB_enum gcb;
+
+    PERL_ARGS_ASSERT_BACKUP_ONE_GCB;
+
+    if (*curpos < strbeg) {
+        return GCB_EDGE;
+    }
+
+    if (utf8_target) {
+        U8 * prev_char_pos = reghopmaybe3(*curpos, -1, strbeg);
+        U8 * prev_prev_char_pos;
+
+        if (! prev_char_pos) {
+            return GCB_EDGE;
+        }
 
-    return GCB_table[before][after];
+        if ((prev_prev_char_pos = reghopmaybe3((U8 *) prev_char_pos, -1, strbeg))) {
+            gcb = getGCB_VAL_UTF8(prev_prev_char_pos, prev_char_pos);
+            *curpos = prev_char_pos;
+            prev_char_pos = prev_prev_char_pos;
+        }
+        else {
+            *curpos = (U8 *) strbeg;
+            return GCB_EDGE;
+        }
+    }
+    else {
+        if (*curpos - 2 < strbeg) {
+            *curpos = (U8 *) strbeg;
+            return GCB_EDGE;
+        }
+        (*curpos)--;
+        gcb = getGCB_VAL_CP(*(*curpos - 1));
+    }
+
+    return gcb;
 }
 
 /* Combining marks attach to most classes that precede them, but this defines
@@ -4326,7 +4602,7 @@ S_isLB(pTHX_ LB_enum before,
 
     PERL_ARGS_ASSERT_ISLB;
 
-    /* Rule numbers in the comments below are as of Unicode 8.0 */
+    /* Rule numbers in the comments below are as of Unicode 9.0 */
 
   redo:
     before = prev;
@@ -4420,14 +4696,14 @@ S_isLB(pTHX_ LB_enum before,
              * that is overriden */
             return LB_table[prev][after] != LB_NOBREAK_EVEN_WITH_SP_BETWEEN;
 
-        case LB_CM_foo:
+        case LB_CM_ZWJ_foo:
 
             /* We don't know how to treat the CM except by looking at the first
-             * non-CM character preceding it */
+             * non-CM character preceding it.  ZWJ is treated as CM */
             do {
                 prev = backup_one_LB(strbeg, &temp_pos, utf8_target);
             }
-            while (prev == LB_Combining_Mark);
+            while (prev == LB_Combining_Mark || prev == LB_ZWJ);
 
             /* Here, 'prev' is that first earlier non-CM character.  If the CM
              * attatches to it, then it inherits the behavior of 'prev'.  If it
@@ -4500,6 +4776,28 @@ S_isLB(pTHX_ LB_enum before,
             return LB_various_then_PO_or_PR;
         }
 
+        case LB_RI_then_RI + LB_NOBREAK:
+        case LB_RI_then_RI + LB_BREAKABLE:
+            {
+                int RI_count = 1;
+
+                /* LB30a Break between two regional indicator symbols if and
+                 * only if there are an even number of regional indicators
+                 * preceding the position of the break.
+                 *
+                 *    sot (RI RI)* RI × RI
+                 *  [^RI] (RI RI)* RI × RI */
+
+                while (backup_one_LB(strbeg,
+                                     &temp_pos,
+                                     utf8_target) == LB_Regional_Indicator)
+                {
+                    RI_count++;
+                }
+
+                return RI_count % 2 == 0;
+            }
+
         default:
             break;
     }
@@ -4884,7 +5182,7 @@ S_isWB(pTHX_ WB_enum previous,
 
     PERL_ARGS_ASSERT_ISWB;
 
-    /* Rule numbers in the comments below are as of Unicode 8.0 */
+    /* Rule numbers in the comments below are as of Unicode 9.0 */
 
   redo:
     before = prev;
@@ -4910,11 +5208,11 @@ S_isWB(pTHX_ WB_enum previous,
          * the beginning of a region of text', the rule is to break before
          * them, just like any other character.  Therefore, the default rule
          * applies and we don't have to look in more depth.  Should this ever
-         * change, we would have to have 2 'case' statements, like in the
-         * rules below, and backup a single character (not spacing over the
-         * extend ones) and then see if that is one of the region-end
-         * characters and go from there */
-        case WB_Ex_or_FO_then_foo:
+         * change, we would have to have 2 'case' statements, like in the rules
+         * below, and backup a single character (not spacing over the extend
+         * ones) and then see if that is one of the region-end characters and
+         * go from there */
+        case WB_Ex_or_FO_or_ZWJ_then_foo:
             prev = backup_one_WB(&previous, strbeg, &before_pos, utf8_target);
             goto redo;
 
@@ -5007,6 +5305,30 @@ S_isWB(pTHX_ WB_enum previous,
             return WB_table[before][after]
                                 - WB_NU_then_MB_or_MN_or_SQ == WB_BREAKABLE;
 
+        case WB_RI_then_RI + WB_NOBREAK:
+        case WB_RI_then_RI + WB_BREAKABLE:
+            {
+                int RI_count = 1;
+
+                /* Do not break within emoji flag sequences. That is, do not
+                 * break between regional indicator (RI) symbols if there is an
+                 * odd number of RI characters before the potential break
+                 * point.
+                 *
+                 * WB15   sot (RI RI)* RI × RI
+                 * WB16 [^RI] (RI RI)* RI × RI */
+
+                while (backup_one_WB(&previous,
+                                     strbeg,
+                                     &before_pos,
+                                     utf8_target) == WB_Regional_Indicator)
+                {
+                    RI_count++;
+                }
+
+                return RI_count % 2 != 1;
+            }
+
         default:
             break;
     }
@@ -5087,8 +5409,8 @@ S_backup_one_WB(pTHX_ WB_enum * previous, const U8 * const strbeg, U8 ** curpos,
             *previous = (*curpos <= strbeg) ? WB_EDGE : WB_UNKNOWN;
         }
 
-        /* And we always back up over these two types */
-        if (wb != WB_Extend && wb != WB_Format) {
+        /* And we always back up over these three types */
+        if (wb != WB_Extend && wb != WB_Format && wb != WB_ZWJ) {
             return wb;
         }
     }
@@ -5119,7 +5441,7 @@ S_backup_one_WB(pTHX_ WB_enum * previous, const U8 * const strbeg, U8 ** curpos,
                 *curpos = (U8 *) strbeg;
                 return WB_EDGE;
             }
-        } while (wb == WB_Extend || wb == WB_Format);
+        } while (wb == WB_Extend || wb == WB_Format || wb == WB_ZWJ);
     }
     else {
         do {
@@ -5135,14 +5457,32 @@ S_backup_one_WB(pTHX_ WB_enum * previous, const U8 * const strbeg, U8 ** curpos,
     return wb;
 }
 
+#define EVAL_CLOSE_PAREN_IS(st,expr)                        \
+(                                                           \
+    (   ( st )                                         ) && \
+    (   ( st )->u.eval.close_paren                     ) && \
+    ( ( ( st )->u.eval.close_paren ) == ( (expr) + 1 ) )    \
+)
+
+#define EVAL_CLOSE_PAREN_IS_TRUE(st,expr)                   \
+(                                                           \
+    (   ( st )                                         ) && \
+    (   ( st )->u.eval.close_paren                     ) && \
+    (   ( expr )                                       ) && \
+    ( ( ( st )->u.eval.close_paren ) == ( (expr) + 1 ) )    \
+)
+
+
+#define EVAL_CLOSE_PAREN_SET(st,expr) \
+    (st)->u.eval.close_paren = ( (expr) + 1 )
+
+#define EVAL_CLOSE_PAREN_CLEAR(st) \
+    (st)->u.eval.close_paren = 0
+
 /* returns -1 on failure, $+[0] on success */
 STATIC SSize_t
 S_regmatch(pTHX_ regmatch_info *reginfo, char *startpos, regnode *prog)
 {
-
-#if PERL_VERSION < 9 && !defined(PERL_CORE)
-    dMY_CXT;
-#endif
     dVAR;
     const bool utf8_target = reginfo->is_utf8_target;
     const U32 uniflags = UTF8_ALLOW_DEFAULT;
@@ -5156,12 +5496,13 @@ S_regmatch(pTHX_ regmatch_info *reginfo, char *startpos, regnode *prog)
     regnode *next;
     U32 n = 0; /* general value; init to avoid compiler warning */
     SSize_t ln = 0; /* len or last;  init to avoid compiler warning */
+    SSize_t endref = 0; /* offset of end of backref when ln is start */
     char *locinput = startpos;
     char *pushinput; /* where to continue after a PUSH */
     I32 nextchr;   /* is always set to UCHARAT(locinput), or -1 at EOS */
 
     bool result = 0;       /* return value of S_regmatch */
-    int depth = 0;         /* depth of backtrack stack */
+    U32 depth = 0;            /* depth of backtrack stack */
     U32 nochange_depth = 0; /* depth of GOSUB recursion with nochange */
     const U32 max_nochange_depth =
         (3 * rex->nparens > MAX_RECURSE_EVAL_NOCHANGE_DEPTH) ?
@@ -5182,7 +5523,7 @@ S_regmatch(pTHX_ regmatch_info *reginfo, char *startpos, regnode *prog)
     SV *sv_yes_mark = NULL; /* last mark name we have seen 
                                during a successful match */
     U32 lastopen = 0;       /* last open we saw */
-    bool has_cutgroup = RX_HAS_CUTGROUP(rex) ? 1 : 0;   
+    bool has_cutgroup = RXp_HAS_CUTGROUP(rex) ? 1 : 0;
     SV* const oreplsv = GvSVn(PL_replgv);
     /* these three flags are set by various ops to signal information to
      * the very next op. They have a useful lifetime of exactly one loop
@@ -5203,12 +5544,20 @@ S_regmatch(pTHX_ regmatch_info *reginfo, char *startpos, regnode *prog)
     U8 gimme = G_SCALAR;
     CV *caller_cv = NULL;      /* who called us */
     CV *last_pushed_cv = NULL; /* most recently called (?{}) CV */
-    CHECKPOINT runops_cp;      /* savestack position before executing EVAL */
     U32 maxopenparen = 0;       /* max '(' index seen so far */
     int to_complement;  /* Invert the result? */
     _char_class_number classnum;
     bool is_utf8_pat = reginfo->is_utf8_pat;
     bool match = FALSE;
+    I32 orig_savestack_ix = PL_savestack_ix;
+    U8 * script_run_begin = NULL;
+
+/* Solaris Studio 12.3 messes up fetching PL_charclass['\n'] */
+#if (defined(__SUNPRO_C) && (__SUNPRO_C == 0x5120) && defined(__x86_64) && defined(USE_64_BIT_ALL))
+#  define SOLARIS_BAD_OPTIMIZER
+    const U32 *pl_charclass_dup = PL_charclass;
+#  define PL_charclass pl_charclass_dup
+#endif
 
 #ifdef DEBUGGING
     GET_RE_DEBUG_FLAGS_DECL;
@@ -5223,18 +5572,18 @@ S_regmatch(pTHX_ regmatch_info *reginfo, char *startpos, regnode *prog)
 
     PERL_ARGS_ASSERT_REGMATCH;
 
-    DEBUG_OPTIMISE_r( DEBUG_EXECUTE_r({
-            Perl_re_printf( aTHX_ "regmatch start\n");
-    }));
-
     st = PL_regmatch_state;
 
     /* Note that nextchr is a byte even in UTF */
     SET_nextchr;
     scan = prog;
-    while (scan != NULL) {
 
+    DEBUG_OPTIMISE_r( DEBUG_EXECUTE_r({
+            DUMP_EXEC_POS( locinput, scan, utf8_target, depth );
+            Perl_re_printf( aTHX_ "regmatch start\n" );
+    }));
 
+    while (scan != NULL) {
        next = scan + NEXT_OFF(scan);
        if (next == scan)
            next = NULL;
@@ -5249,7 +5598,7 @@ S_regmatch(pTHX_ regmatch_info *reginfo, char *startpos, regnode *prog)
                 DUMP_EXEC_POS( locinput, scan, utf8_target, depth );
                 regprop(rex, prop, scan, reginfo, NULL);
                 Perl_re_printf( aTHX_
-                    "%*s%"IVdf":%s(%"IVdf")\n",
+                    "%*s%" IVdf ":%s(%" IVdf ")\n",
                     INDENT_CHARS(depth), "",
                     (IV)(scan - rexi->program),
                     SvPVX_const(prop),
@@ -5396,6 +5745,7 @@ S_regmatch(pTHX_ regmatch_info *reginfo, char *startpos, regnode *prog)
                 if (scan->flags == EXACTL || scan->flags == EXACTFLU8) {
                     _CHECK_AND_WARN_PROBLEMATIC_LOCALE;
                     if (utf8_target
+                        && nextchr >= 0 /* guard against negative EOS value in nextchr */
                         && UTF8_IS_ABOVE_LATIN1(nextchr)
                         && scan->flags == EXACTL)
                     {
@@ -5472,9 +5822,10 @@ S_regmatch(pTHX_ regmatch_info *reginfo, char *startpos, regnode *prog)
 
                    DEBUG_TRIE_EXECUTE_r({
                                 DUMP_EXEC_POS( (char *)uc, scan, utf8_target, depth );
-                                Perl_re_exec_indentf( aTHX_
-                                    "%sState: %4"UVxf" Accepted: %c ",
-                                    depth, PL_colors[4],
+                                /* HERE */
+                                PerlIO_printf( Perl_debug_log,
+                                    "%*s%sState: %4" UVxf " Accepted: %c ",
+                                    INDENT_CHARS(depth), "", PL_colors[4],
                                    (UV)state, (accepted ? 'Y' : 'N'));
                    });
 
@@ -5507,7 +5858,7 @@ S_regmatch(pTHX_ regmatch_info *reginfo, char *startpos, regnode *prog)
                    }
                    DEBUG_TRIE_EXECUTE_r(
                         Perl_re_printf( aTHX_
-                           "Charid:%3x CP:%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] );
                    );
                }
@@ -5526,7 +5877,7 @@ S_regmatch(pTHX_ regmatch_info *reginfo, char *startpos, regnode *prog)
                }
 
                DEBUG_EXECUTE_r(
-                    Perl_re_exec_indentf( aTHX_  "%sgot %"IVdf" possible matches%s\n",
+                    Perl_re_exec_indentf( aTHX_  "%sgot %" IVdf " possible matches%s\n",
                         depth,
                        PL_colors[4], (IV)ST.accepted, PL_colors[5] );
                );
@@ -5537,7 +5888,12 @@ S_regmatch(pTHX_ regmatch_info *reginfo, char *startpos, regnode *prog)
        case TRIE_next_fail: /* we failed - try next alternative */
         {
             U8 *uc;
-            if ( ST.jump) {
+            if ( ST.jump ) {
+                /* undo any captures done in the tail part of a branch,
+                 * e.g.
+                 *    /(?:X(.)(.)|Y(.)).../
+                 * where the trie just matches X then calls out to do the
+                 * rest of the branch */
                 REGCP_UNWIND(ST.cp);
                 UNWIND_PAREN(ST.lastparen, ST.lastcloseparen);
            }
@@ -5571,7 +5927,7 @@ S_regmatch(pTHX_ regmatch_info *reginfo, char *startpos, regnode *prog)
                 no_final = 0;
             }
 
-            if ( ST.jump) {
+            if ( ST.jump ) {
                 ST.lastparen = rex->lastparen;
                 ST.lastcloseparen = rex->lastcloseparen;
                REGCP_SET(ST.cp);
@@ -5642,7 +5998,7 @@ S_regmatch(pTHX_ regmatch_info *reginfo, char *startpos, regnode *prog)
                    );
            });
 
-           if (ST.accepted > 1 || has_cutgroup) {
+           if ( ST.accepted > 1 || has_cutgroup || ST.jump ) {
                PUSH_STATE_GOTO(TRIE_next, scan, (char*)uc);
                NOT_REACHED; /* NOTREACHED */
            }
@@ -5871,12 +6227,14 @@ S_regmatch(pTHX_ regmatch_info *reginfo, char *startpos, regnode *prog)
                if (locinput == reginfo->strbeg)
                    b1 = isWORDCHAR_LC('\n');
                else {
-                    b1 = isWORDCHAR_LC_utf8(reghop3((U8*)locinput, -1,
-                                                        (U8*)(reginfo->strbeg)));
+                    b1 = isWORDCHAR_LC_utf8_safe(reghop3((U8*)locinput, -1,
+                                                        (U8*)(reginfo->strbeg)),
+                                                 (U8*)(reginfo->strend));
                }
                 b2 = (NEXTCHR_IS_EOS)
                     ? isWORDCHAR_LC('\n')
-                    : isWORDCHAR_LC_utf8((U8*)locinput);
+                    : isWORDCHAR_LC_utf8_safe((U8*) locinput,
+                                              (U8*) reginfo->strend);
            }
            else { /* Here the string isn't utf8 */
                b1 = (locinput == reginfo->strbeg)
@@ -5950,11 +6308,15 @@ S_regmatch(pTHX_ regmatch_info *reginfo, char *startpos, regnode *prog)
                         bool b1, b2;
                         b1 = (locinput == reginfo->strbeg)
                              ? 0 /* isWORDCHAR_L1('\n') */
-                             : isWORDCHAR_utf8(reghop3((U8*)locinput, -1,
-                                                                (U8*)(reginfo->strbeg)));
+                             : isWORDCHAR_utf8_safe(
+                                               reghop3((U8*)locinput,
+                                                       -1,
+                                                       (U8*)(reginfo->strbeg)),
+                                                    (U8*) reginfo->strend);
                         b2 = (NEXTCHR_IS_EOS)
                             ? 0 /* isWORDCHAR_L1('\n') */
-                            : isWORDCHAR_utf8((U8*)locinput);
+                            : isWORDCHAR_utf8_safe((U8*)locinput,
+                                                   (U8*) reginfo->strend);
                         match = cBOOL(b1 != b2);
                         break;
                     }
@@ -5972,7 +6334,10 @@ S_regmatch(pTHX_ regmatch_info *reginfo, char *startpos, regnode *prog)
                                                         (U8*)(reginfo->strbeg)),
                                                 (U8*) reginfo->strend),
                                           getGCB_VAL_UTF8((U8*) locinput,
-                                                        (U8*) reginfo->strend));
+                                                        (U8*) reginfo->strend),
+                                          (U8*) reginfo->strbeg,
+                                          (U8*) locinput,
+                                          utf8_target);
                         }
                         break;
 
@@ -6143,6 +6508,22 @@ S_regmatch(pTHX_ regmatch_info *reginfo, char *startpos, regnode *prog)
            }
            break;
 
+        case ASCII:
+            if (NEXTCHR_IS_EOS || ! isASCII(UCHARAT(locinput))) {
+                sayNO;
+            }
+
+            locinput++;     /* ASCII is always single byte */
+            break;
+
+        case NASCII:
+            if (NEXTCHR_IS_EOS || isASCII(UCHARAT(locinput))) {
+                sayNO;
+            }
+
+            goto increment_locinput;
+            break;
+
         /* The argument (FLAGS) to all the POSIX node types is the class number
          * */
 
@@ -6162,23 +6543,28 @@ S_regmatch(pTHX_ regmatch_info *reginfo, char *startpos, regnode *prog)
                 if (! (to_complement ^ cBOOL(isFOO_lc(FLAGS(scan), (U8) nextchr)))) {
                     sayNO;
                 }
+
+                locinput++;
+                break;
             }
-            else if (UTF8_IS_DOWNGRADEABLE_START(nextchr)) {
-                if (! (to_complement ^ cBOOL(isFOO_lc(FLAGS(scan),
-                                               EIGHT_BIT_UTF8_TO_NATIVE(nextchr,
-                                               *(locinput + 1))))))
-                {
-                    sayNO;
-                }
-            }
-            else { /* Here, must be an above Latin-1 code point */
-                _CHECK_AND_OUTPUT_WIDE_LOCALE_UTF8_MSG(locinput, reginfo->strend);
+
+            if (! UTF8_IS_NEXT_CHAR_DOWNGRADEABLE(locinput, reginfo->strend)) {
+                /* An above Latin-1 code point, or malformed */
+                _CHECK_AND_OUTPUT_WIDE_LOCALE_UTF8_MSG(locinput,
+                                                       reginfo->strend);
                 goto utf8_posix_above_latin1;
             }
 
-            /* Here, must be utf8 */
-            locinput += UTF8SKIP(locinput);
-            break;
+            /* Here is a UTF-8 variant code point below 256 and the target is
+             * UTF-8 */
+            if (! (to_complement ^ cBOOL(isFOO_lc(FLAGS(scan),
+                                            EIGHT_BIT_UTF8_TO_NATIVE(nextchr,
+                                            *(locinput + 1))))))
+            {
+                sayNO;
+            }
+
+            goto increment_locinput;
 
         case NPOSIXD:   /* \W or [:^punct:] etc. under /d */
             to_complement = 1;
@@ -6249,7 +6635,7 @@ S_regmatch(pTHX_ regmatch_info *reginfo, char *startpos, regnode *prog)
                 }
                 locinput++;
             }
-            else if (UTF8_IS_DOWNGRADEABLE_START(nextchr)) {
+            else if (UTF8_IS_NEXT_CHAR_DOWNGRADEABLE(locinput, reginfo->strend)) {
                 if (! (to_complement
                        ^ cBOOL(_generic_isCC(EIGHT_BIT_UTF8_TO_NATIVE(nextchr,
                                                                *(locinput + 1)),
@@ -6354,7 +6740,10 @@ S_regmatch(pTHX_ regmatch_info *reginfo, char *startpos, regnode *prog)
                 while (locinput < reginfo->strend) {
                     GCB_enum cur_gcb = getGCB_VAL_UTF8((U8*) locinput,
                                                          (U8*) reginfo->strend);
-                    if (isGCB(prev_gcb, cur_gcb)) {
+                    if (isGCB(prev_gcb, cur_gcb,
+                              (U8*) reginfo->strbeg, (U8*) locinput,
+                              utf8_target))
+                    {
                         break;
                     }
 
@@ -6459,10 +6848,11 @@ S_regmatch(pTHX_ regmatch_info *reginfo, char *startpos, regnode *prog)
 
          do_nref_ref_common:
            ln = rex->offs[n].start;
+           endref = rex->offs[n].end;
            reginfo->poscache_iter = reginfo->poscache_maxiter; /* Void cache */
-           if (rex->lastparen < n || ln == -1)
+           if (rex->lastparen < n || ln == -1 || endref == -1)
                sayNO;                  /* Do not match unless seen CLOSEn. */
-           if (ln == rex->offs[n].end)
+           if (ln == endref)
                break;
 
            s = reginfo->strbeg + ln;
@@ -6476,7 +6866,7 @@ S_regmatch(pTHX_ regmatch_info *reginfo, char *startpos, regnode *prog)
                     * not going off the end given by reginfo->strend, and
                     * returns in <limit> upon success, how much of the
                     * current input was matched */
-               if (! foldEQ_utf8_flags(s, NULL, rex->offs[n].end - ln, utf8_target,
+               if (! foldEQ_utf8_flags(s, NULL, endref - ln, utf8_target,
                                    locinput, &limit, 0, utf8_target, utf8_fold_flags))
                {
                    sayNO;
@@ -6491,7 +6881,7 @@ S_regmatch(pTHX_ regmatch_info *reginfo, char *startpos, regnode *prog)
                (type == REF ||
                 UCHARAT(s) != fold_array[nextchr]))
                sayNO;
-           ln = rex->offs[n].end - ln;
+           ln = endref - ln;
            if (locinput + ln > reginfo->strend)
                sayNO;
            if (ln > 1 && (type == REF
@@ -6570,7 +6960,7 @@ S_regmatch(pTHX_ regmatch_info *reginfo, char *startpos, regnode *prog)
             goto eval_recurse_doit;
             /* NOTREACHED */
 
-        case EVAL:  /*   /(?{A})B/   /(??{A})B/  and /(?(?{A})X|Y)B/   */        
+        case EVAL:  /*   /(?{...})B/   /(??{A})B/  and  /(?(?{...})X|Y)B/   */
             if (cur_eval && cur_eval->locinput==locinput) {
                if ( ++nochange_depth > max_nochange_depth )
                     Perl_croak(aTHX_ "EVAL without pos change exceeded limit in regex");
@@ -6588,8 +6978,8 @@ S_regmatch(pTHX_ regmatch_info *reginfo, char *startpos, regnode *prog)
                CV *newcv;
 
                /* save *all* paren positions */
-               regcppush(rex, 0, maxopenparen);
-               REGCP_SET(runops_cp);
+                regcppush(rex, 0, maxopenparen);
+                REGCP_SET(ST.lastcp);
 
                if (!caller_cv)
                    caller_cv = find_runcv(NULL);
@@ -6614,30 +7004,67 @@ S_regmatch(pTHX_ regmatch_info *reginfo, char *startpos, regnode *prog)
                    nop = (OP*)rexi->data->data[n];
                }
 
-               /* normally if we're about to execute code from the same
-                * CV that we used previously, we just use the existing
-                * CX stack entry. However, its possible that in the
-                * meantime we may have backtracked, popped from the save
-                * stack, and undone the SAVECOMPPAD(s) associated with
-                * PUSH_MULTICALL; in which case PL_comppad no longer
-                * points to newcv's pad. */
+                /* Some notes about MULTICALL and the context and save stacks.
+                 *
+                 * In something like
+                 *   /...(?{ my $x)}...(?{ my $y)}...(?{ my $z)}.../
+                 * since codeblocks don't introduce a new scope (so that
+                 * local() etc accumulate), at the end of a successful
+                 * match there will be a SAVEt_CLEARSV on the savestack
+                 * for each of $x, $y, $z. If the three code blocks above
+                 * happen to have come from different CVs (e.g. via
+                 * embedded qr//s), then we must ensure that during any
+                 * savestack unwinding, PL_comppad always points to the
+                 * right pad at each moment. We achieve this by
+                 * interleaving SAVEt_COMPPAD's on the savestack whenever
+                 * there is a change of pad.
+                 * In theory whenever we call a code block, we should
+                 * push a CXt_SUB context, then pop it on return from
+                 * that code block. This causes a bit of an issue in that
+                 * normally popping a context also clears the savestack
+                 * back to cx->blk_oldsaveix, but here we specifically
+                 * don't want to clear the save stack on exit from the
+                 * code block.
+                 * Also for efficiency we don't want to keep pushing and
+                 * popping the single SUB context as we backtrack etc.
+                 * So instead, we push a single context the first time
+                 * we need, it, then hang onto it until the end of this
+                 * function. Whenever we encounter a new code block, we
+                 * update the CV etc if that's changed. During the times
+                 * in this function where we're not executing a code
+                 * block, having the SUB context still there is a bit
+                 * naughty - but we hope that no-one notices.
+                 * When the SUB context is initially pushed, we fake up
+                 * cx->blk_oldsaveix to be as if we'd pushed this context
+                 * on first entry to S_regmatch rather than at some random
+                 * point during the regexe execution. That way if we
+                 * croak, popping the context stack will ensure that
+                 * *everything* SAVEd by this function is undone and then
+                 * the context popped, rather than e.g., popping the
+                 * context (and restoring the original PL_comppad) then
+                 * popping more of the savestack and restoring a bad
+                 * PL_comppad.
+                 */
+
+                /* If this is the first EVAL, push a MULTICALL. On
+                 * subsequent calls, if we're executing a different CV, or
+                 * if PL_comppad has got messed up from backtracking
+                 * through SAVECOMPPADs, then refresh the context.
+                 */
                if (newcv != last_pushed_cv || PL_comppad != last_pad)
                {
                     U8 flags = (CXp_SUB_RE |
                                 ((newcv == caller_cv) ? CXp_SUB_RE_FAKE : 0));
+                    SAVECOMPPAD();
                    if (last_pushed_cv) {
-                        /* PUSH/POP_MULTICALL save and restore the
-                         * caller's PL_comppad; if we call multiple subs
-                         * using the same CX block, we have to save and
-                         * unwind the varying PL_comppad's ourselves,
-                         * especially restoring the right PL_comppad on
-                         * backtrack - so save it on the save stack */
-                        SAVECOMPPAD();
                        CHANGE_MULTICALL_FLAGS(newcv, flags);
                    }
                    else {
                        PUSH_MULTICALL_FLAGS(newcv, flags);
                    }
+                    /* see notes above */
+                    CX_CUR()->blk_oldsaveix = orig_savestack_ix;
+
                    last_pushed_cv = newcv;
                }
                else {
@@ -6680,7 +7107,7 @@ S_regmatch(pTHX_ regmatch_info *reginfo, char *startpos, regnode *prog)
                nop = nop->op_next;
 
                 DEBUG_STATE_r( Perl_re_printf( aTHX_
-                   "  re EVAL PL_op=0x%"UVxf"\n", PTR2UV(nop)) );
+                   "  re EVAL PL_op=0x%" UVxf "\n", PTR2UV(nop)) );
 
                rex->offs[0].end = locinput - reginfo->strbeg;
                 if (reginfo->info_aux_eval->pos_magic)
@@ -6719,7 +7146,7 @@ S_regmatch(pTHX_ regmatch_info *reginfo, char *startpos, regnode *prog)
                if (logical == 0)        /*   (?{})/   */
                    sv_setsv(save_scalar(PL_replgv), ret); /* $^R */
                else if (logical == 1) { /*   /(?(?{...})X|Y)/    */
-                   sw = cBOOL(SvTRUE(ret));
+                   sw = cBOOL(SvTRUE_NN(ret));
                    logical = 0;
                }
                else {                   /*  /(??{})  */
@@ -6754,11 +7181,14 @@ S_regmatch(pTHX_ regmatch_info *reginfo, char *startpos, regnode *prog)
                 * in the regexp code uses the pad ! */
                PL_op = oop;
                PL_curcop = ocurcop;
-               S_regcp_restore(aTHX_ rex, runops_cp, &maxopenparen);
-               PL_curpm = PL_reg_curpm;
+                regcp_restore(rex, ST.lastcp, &maxopenparen);
+                PL_curpm_under = PL_curpm;
+                PL_curpm = PL_reg_curpm;
 
-               if (logical != 2)
-                   break;
+               if (logical != 2) {
+                    PUSH_STATE_GOTO(EVAL_B, next, locinput);
+                   /* NOTREACHED */
+                }
            }
 
                /* only /(??{})/  from now on */
@@ -6856,11 +7286,12 @@ S_regmatch(pTHX_ regmatch_info *reginfo, char *startpos, regnode *prog)
                ST.prev_eval = cur_eval;
                cur_eval = st;
                /* now continue from first node in postoned RE */
-               PUSH_YES_STATE_GOTO(EVAL_AB, startpoint, locinput);
+               PUSH_YES_STATE_GOTO(EVAL_postponed_AB, startpoint, locinput);
                NOT_REACHED; /* NOTREACHED */
        }
 
-       case EVAL_AB: /* cleanup after a successful (??{A})B */
+       case EVAL_postponed_AB: /* cleanup after a successful (??{A})B */
+            /* note: this is called twice; first after popping B, then A */
             DEBUG_STACK_r({
                 Perl_re_exec_indentf( aTHX_  "EVAL_AB cur_eval=%p prev_eval=%p\n",
                     depth, cur_eval, ST.prev_eval);
@@ -6868,8 +7299,8 @@ S_regmatch(pTHX_ regmatch_info *reginfo, char *startpos, regnode *prog)
 
 #define SET_RECURSE_LOCINPUT(STR,VAL)\
             if ( cur_eval && CUR_EVAL.close_paren ) {\
-                DEBUG_EXECUTE_r({ \
-                    Perl_re_exec_indentf( aTHX_  "EVAL_AB[before] GOSUB%d ce=%p recurse_locinput=%p\n",\
+                DEBUG_STACK_r({ \
+                    Perl_re_exec_indentf( aTHX_  STR " GOSUB%d ce=%p recurse_locinput=%p\n",\
                         depth,    \
                         CUR_EVAL.close_paren - 1,\
                         cur_eval, \
@@ -6905,7 +7336,11 @@ S_regmatch(pTHX_ regmatch_info *reginfo, char *startpos, regnode *prog)
            sayYES;
 
 
-       case EVAL_AB_fail: /* unsuccessfully ran A or B in (??{A})B */
+       case EVAL_B_fail: /* unsuccessful B in (?{...})B */
+           REGCP_UNWIND(ST.lastcp);
+            sayNO;
+
+       case EVAL_postponed_AB_fail: /* unsuccessfully ran A or B in (??{A})B */
            /* note: this is called twice; first after popping B, then A */
             DEBUG_STACK_r({
                 Perl_re_exec_indentf( aTHX_  "EVAL_AB_fail cur_eval=%p prev_eval=%p\n",
@@ -6921,7 +7356,7 @@ S_regmatch(pTHX_ regmatch_info *reginfo, char *startpos, regnode *prog)
            rexi = RXi_GET(rex); 
 
            REGCP_UNWIND(ST.lastcp);
-           regcppop(rex, &maxopenparen);
+            regcppop(rex, &maxopenparen);
            cur_eval = ST.prev_eval;
            cur_curlyx = ST.prev_curlyx;
 
@@ -6939,8 +7374,9 @@ S_regmatch(pTHX_ regmatch_info *reginfo, char *startpos, regnode *prog)
            rex->offs[n].start_tmp = locinput - reginfo->strbeg;
            if (n > maxopenparen)
                maxopenparen = n;
-            DEBUG_BUFFERS_r(Perl_re_printf( aTHX_
-               "rex=0x%"UVxf" offs=0x%"UVxf": \\%"UVuf": set %"IVdf" tmp; maxopenparen=%"UVuf"\n",
+            DEBUG_BUFFERS_r(Perl_re_exec_indentf( aTHX_
+               "rex=0x%" UVxf " offs=0x%" UVxf ": \\%" UVuf ": set %" IVdf " tmp; maxopenparen=%" UVuf "\n",
+                depth,
                PTR2UV(rex),
                PTR2UV(rex->offs),
                (UV)n,
@@ -6950,12 +7386,17 @@ S_regmatch(pTHX_ regmatch_info *reginfo, char *startpos, regnode *prog)
             lastopen = n;
            break;
 
+        case SROPEN: /*  (*SCRIPT_RUN:  */
+            script_run_begin = (U8 *) locinput;
+            break;
+
 /* XXX really need to log other places start/end are set too */
 #define CLOSE_CAPTURE                                                      \
     rex->offs[n].start = rex->offs[n].start_tmp;                           \
     rex->offs[n].end = locinput - reginfo->strbeg;                         \
-    DEBUG_BUFFERS_r(Perl_re_printf( aTHX_                                              \
-        "rex=0x%"UVxf" offs=0x%"UVxf": \\%"UVuf": set %"IVdf"..%"IVdf"\n", \
+    DEBUG_BUFFERS_r(Perl_re_exec_indentf( aTHX_                            \
+        "rex=0x%" UVxf " offs=0x%" UVxf ": \\%" UVuf ": set %" IVdf "..%" IVdf "\n", \
+        depth,                                                             \
         PTR2UV(rex),                                                       \
         PTR2UV(rex->offs),                                                 \
         (UV)n,                                                             \
@@ -6974,6 +7415,16 @@ S_regmatch(pTHX_ regmatch_info *reginfo, char *startpos, regnode *prog)
 
            break;
 
+        case SRCLOSE:  /*  (*SCRIPT_RUN: ... )   */
+
+            if (! isSCRIPT_RUN(script_run_begin, (U8 *) locinput, utf8_target))
+            {
+                sayNO;
+            }
+
+            break;
+
+
         case ACCEPT:  /*  (*ACCEPT)  */
             if (scan->flags)
                 sv_yes_mark = MUTABLE_SV(rexi->data->data[ ARG( scan ) ]);
@@ -7011,6 +7462,8 @@ S_regmatch(pTHX_ regmatch_info *reginfo, char *startpos, regnode *prog)
 
         case INSUBP:   /*  (?(R))  */
             n = ARG(scan);
+            /* this does not need to use EVAL_CLOSE_PAREN macros, as the arg
+             * of SCAN is already set up as matches a eval.close_paren */
             sw = cur_eval && (n == 0 || CUR_EVAL.close_paren == n);
             break;
 
@@ -7190,8 +7643,7 @@ NULL
            /* First just match a string of min A's. */
 
            if (n < min) {
-               ST.cp = regcppush(rex, cur_curlyx->u.curlyx.parenfloor,
-                                    maxopenparen);
+                ST.cp = regcppush(rex, cur_curlyx->u.curlyx.parenfloor, maxopenparen);
                cur_curlyx->u.curlyx.lastloc = locinput;
                REGCP_SET(ST.lastcp);
 
@@ -7289,6 +7741,7 @@ NULL
                         DEBUG_EXECUTE_r( Perl_re_exec_indentf( aTHX_  "whilem: (cache) already tried at this position...\n",
                             depth)
                        );
+                        cur_curlyx->u.curlyx.count--;
                        sayNO; /* cache records failure */
                    }
                    ST.cache_offset = offset;
@@ -7301,9 +7754,6 @@ NULL
            if (cur_curlyx->u.curlyx.minmod) {
                ST.save_curlyx = cur_curlyx;
                cur_curlyx = cur_curlyx->u.curlyx.prev_curlyx;
-               ST.cp = regcppush(rex, ST.save_curlyx->u.curlyx.parenfloor,
-                            maxopenparen);
-               REGCP_SET(ST.lastcp);
                PUSH_YES_STATE_GOTO(WHILEM_B_min, ST.save_curlyx->u.curlyx.B,
                                     locinput);
                NOT_REACHED; /* NOTREACHED */
@@ -7312,7 +7762,7 @@ NULL
            /* Prefer A over B for maximal matching. */
 
            if (n < max) { /* More greed allowed? */
-               ST.cp = regcppush(rex, cur_curlyx->u.curlyx.parenfloor,
+                ST.cp = regcppush(rex, cur_curlyx->u.curlyx.parenfloor,
                             maxopenparen);
                cur_curlyx->u.curlyx.lastloc = locinput;
                REGCP_SET(ST.lastcp);
@@ -7336,11 +7786,11 @@ NULL
            CACHEsayNO;
            NOT_REACHED; /* NOTREACHED */
 
-       case WHILEM_A_min_fail: /* just failed to match A in a minimal match */
-           /* FALLTHROUGH */
        case WHILEM_A_pre_fail: /* just failed to match even minimal A */
            REGCP_UNWIND(ST.lastcp);
-           regcppop(rex, &maxopenparen);
+            regcppop(rex, &maxopenparen);
+           /* FALLTHROUGH */
+       case WHILEM_A_min_fail: /* just failed to match A in a minimal match */
            cur_curlyx->u.curlyx.lastloc = ST.save_lastloc;
            cur_curlyx->u.curlyx.count--;
            CACHEsayNO;
@@ -7348,7 +7798,7 @@ NULL
 
        case WHILEM_A_max_fail: /* just failed to match A in a maximal match */
            REGCP_UNWIND(ST.lastcp);
-           regcppop(rex, &maxopenparen); /* Restore some previous $<digit>s? */
+            regcppop(rex, &maxopenparen); /* Restore some previous $<digit>s? */
             DEBUG_EXECUTE_r(Perl_re_exec_indentf( aTHX_  "whilem: failed, trying continuation...\n",
                 depth)
            );
@@ -7373,8 +7823,6 @@ NULL
 
        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, &maxopenparen);
 
            if (cur_curlyx->u.curlyx.count >= /*max*/ARG2(cur_curlyx->u.curlyx.me)) {
                /* Maximum greed exceeded */
@@ -7396,9 +7844,6 @@ NULL
            );
            /* Try grabbing another A and see if it helps. */
            cur_curlyx->u.curlyx.lastloc = locinput;
-           ST.cp = regcppush(rex, cur_curlyx->u.curlyx.parenfloor,
-                            maxopenparen);
-           REGCP_SET(ST.lastcp);
            PUSH_STATE_GOTO(WHILEM_A_min,
                /*A*/ NEXTOPER(ST.save_curlyx->u.curlyx.me) + EXTRA_STEP_2ARGS,
                 locinput);
@@ -7531,11 +7976,11 @@ NULL
                    ST.count = ST.minmod ? ARG1(ST.me) : ARG2(ST.me);
            }
            DEBUG_EXECUTE_r(
-                Perl_re_exec_indentf( aTHX_  "CURLYM now matched %"IVdf" times, len=%"IVdf"...\n",
+                Perl_re_exec_indentf( aTHX_  "CURLYM now matched %" IVdf " times, len=%" IVdf "...\n",
                           depth, (IV) ST.count, (IV)ST.alen)
            );
 
-            if (EVAL_CLOSE_PAREN_IS(cur_eval,(U32)ST.me->flags))
+            if (EVAL_CLOSE_PAREN_IS_TRUE(cur_eval,(U32)ST.me->flags))
                goto fake_end;
                
            {
@@ -7550,7 +7995,7 @@ NULL
 
 
            if (ST.minmod || ST.count < ARG1(ST.me) /* min*/ 
-                || EVAL_CLOSE_PAREN_IS(cur_eval,(U32)ST.me->flags))
+                || EVAL_CLOSE_PAREN_IS_TRUE(cur_eval,(U32)ST.me->flags))
                sayNO;
 
          curlym_do_B: /* execute the B in /A{m,n}B/  */
@@ -7584,7 +8029,7 @@ NULL
            }
 
            DEBUG_EXECUTE_r(
-                Perl_re_exec_indentf( aTHX_  "CURLYM trying tail with matches=%"IVdf"...\n",
+                Perl_re_exec_indentf( aTHX_  "CURLYM trying tail with matches=%" IVdf "...\n",
                     depth, (IV)ST.count)
                );
            if (! NEXTCHR_IS_EOS && ST.c1 != CHRTEST_VOID) {
@@ -7594,7 +8039,7 @@ NULL
                     {
                         /* simulate B failing */
                         DEBUG_OPTIMISE_r(
-                            Perl_re_exec_indentf( aTHX_  "CURLYM Fast bail next target=0x%"UVXf" c1=0x%"UVXf" c2=0x%"UVXf"\n",
+                            Perl_re_exec_indentf( aTHX_  "CURLYM Fast bail next target=0x%" UVXf " c1=0x%" UVXf " c2=0x%" UVXf "\n",
                                 depth,
                                 valid_utf8_to_uvchr((U8 *) locinput, NULL),
                                 valid_utf8_to_uvchr(ST.c1_utf8, NULL),
@@ -7630,7 +8075,7 @@ NULL
                else
                    rex->offs[paren].end = -1;
 
-                if (EVAL_CLOSE_PAREN_IS(cur_eval,(U32)ST.me->flags))
+                if (EVAL_CLOSE_PAREN_IS_TRUE(cur_eval,(U32)ST.me->flags))
                {
                    if (ST.count) 
                        goto fake_end;
@@ -7699,7 +8144,7 @@ NULL
                maxopenparen = ST.paren;
            ST.min = ARG1(scan);  /* min to match */
            ST.max = ARG2(scan);  /* max to match */
-            if (EVAL_CLOSE_PAREN_IS(cur_eval,(U32)ST.paren))
+            if (EVAL_CLOSE_PAREN_IS_TRUE(cur_eval,(U32)ST.paren))
             {
                ST.min=1;
                ST.max=1;
@@ -7762,7 +8207,7 @@ NULL
                 char *li = locinput;
                minmod = 0;
                if (ST.min &&
-                        regrepeat(rex, &li, ST.A, reginfo, ST.min, depth)
+                        regrepeat(rex, &li, ST.A, reginfo, ST.min)
                             < ST.min)
                    sayNO;
                 SET_locinput(li);
@@ -7799,7 +8244,7 @@ NULL
                 /* avoid taking address of locinput, so it can remain
                  * a register var */
                 char *li = locinput;
-               ST.count = regrepeat(rex, &li, ST.A, reginfo, ST.max, depth);
+                ST.count = regrepeat(rex, &li, ST.A, reginfo, ST.max);
                if (ST.count < ST.min)
                    sayNO;
                 SET_locinput(li);
@@ -7862,16 +8307,46 @@ NULL
                }
                else {  /* Not utf8_target */
                    if (ST.c1 == ST.c2) {
-                       while (locinput <= ST.maxpos &&
-                              UCHARAT(locinput) != ST.c1)
-                           locinput++;
-                   }
-                   else {
-                       while (locinput <= ST.maxpos
-                              && UCHARAT(locinput) != ST.c1
-                              && UCHARAT(locinput) != ST.c2)
-                           locinput++;
+                        locinput = (char *) memchr(locinput,
+                                                   ST.c1,
+                                                   ST.maxpos + 1 - locinput);
+                        if (! locinput) {
+                            locinput = ST.maxpos + 1;
+                        }
                    }
+                    else {
+                        U8 c1_c2_bits_differing = ST.c1 ^ ST.c2;
+
+                        if (! isPOWER_OF_2(c1_c2_bits_differing)) {
+                            while (   locinput <= ST.maxpos
+                                   && UCHARAT(locinput) != ST.c1
+                                   && UCHARAT(locinput) != ST.c2)
+                            {
+                                locinput++;
+                            }
+                        }
+                        else {
+                            /* If c1 and c2 only differ by a single bit, we can
+                             * avoid a conditional each time through the loop,
+                             * at the expense of a little preliminary setup and
+                             * an extra mask each iteration.  By masking out
+                             * that bit, we match exactly two characters, c1
+                             * and c2, and so we don't have to test for both.
+                             * On both ASCII and EBCDIC platforms, most of the
+                             * ASCII-range and Latin1-range folded equivalents
+                             * differ only in a single bit, so this is actually
+                             * the most common case. (e.g. 'A' 0x41 vs 'a'
+                             * 0x61). */
+                            U8 c1_masked = ST.c1 &~ c1_c2_bits_differing;
+                            U8 c1_c2_mask = ~ c1_c2_bits_differing;
+                            while (   locinput <= ST.maxpos
+                                   && (UCHARAT(locinput) & c1_c2_mask)
+                                                                != c1_masked)
+                            {
+                                locinput++;
+                            }
+                        }
+                    }
                    n = locinput - ST.oldloc;
                }
                if (locinput > ST.maxpos)
@@ -7882,12 +8357,12 @@ NULL
                      * locinput matches */
                     char *li = ST.oldloc;
                    ST.count += n;
-                   if (regrepeat(rex, &li, ST.A, reginfo, n, depth) < n)
+                    if (regrepeat(rex, &li, ST.A, reginfo, n) < n)
                        sayNO;
                     assert(n == REG_INFTY || locinput == li);
                }
                CURLY_SETPAREN(ST.paren, ST.count);
-                if (EVAL_CLOSE_PAREN_IS(cur_eval,(U32)ST.paren))
+                if (EVAL_CLOSE_PAREN_IS_TRUE(cur_eval,(U32)ST.paren))
                    goto fake_end;
                PUSH_STATE_GOTO(CURLY_B_min_known, ST.B, locinput);
            }
@@ -7903,7 +8378,7 @@ NULL
            /* failed -- move forward one */
             {
                 char *li = locinput;
-                if (!regrepeat(rex, &li, ST.A, reginfo, 1, depth)) {
+                if (!regrepeat(rex, &li, ST.A, reginfo, 1)) {
                     sayNO;
                 }
                 locinput = li;
@@ -7915,7 +8390,7 @@ NULL
                {
                  curly_try_B_min:
                    CURLY_SETPAREN(ST.paren, ST.count);
-                    if (EVAL_CLOSE_PAREN_IS(cur_eval,(U32)ST.paren))
+                    if (EVAL_CLOSE_PAREN_IS_TRUE(cur_eval,(U32)ST.paren))
                         goto fake_end;
                    PUSH_STATE_GOTO(CURLY_B_min, ST.B, locinput);
                }
@@ -7925,7 +8400,7 @@ NULL
 
           curly_try_B_max:
            /* a successful greedy match: now try to match B */
-            if (EVAL_CLOSE_PAREN_IS(cur_eval,(U32)ST.paren))
+            if (EVAL_CLOSE_PAREN_IS_TRUE(cur_eval,(U32)ST.paren))
                 goto fake_end;
            {
                bool could_match = locinput < reginfo->strend;
@@ -7977,20 +8452,21 @@ NULL
                st->u.eval.prev_rex = rex_sv;           /* inner */
 
                 /* Save *all* the positions. */
-               st->u.eval.cp = regcppush(rex, 0, maxopenparen);
+                st->u.eval.cp = regcppush(rex, 0, maxopenparen);
                 rex_sv = CUR_EVAL.prev_rex;
                is_utf8_pat = reginfo->is_utf8_pat = cBOOL(RX_UTF8(rex_sv));
                SET_reg_curpm(rex_sv);
                rex = ReANY(rex_sv);
                rexi = RXi_GET(rex);
+
+                st->u.eval.prev_curlyx = cur_curlyx;
                 cur_curlyx = CUR_EVAL.prev_curlyx;
 
                REGCP_SET(st->u.eval.lastcp);
 
                /* Restore parens of the outer rex without popping the
                 * savestack */
-                S_regcp_restore(aTHX_ rex, CUR_EVAL.lastcp,
-                                        &maxopenparen);
+                regcp_restore(rex, CUR_EVAL.lastcp, &maxopenparen);
 
                st->u.eval.prev_eval = cur_eval;
                 cur_eval = CUR_EVAL.prev_eval;
@@ -8002,7 +8478,7 @@ NULL
 
                 SET_RECURSE_LOCINPUT("FAKE-END[after]", cur_eval->locinput);
 
-                PUSH_YES_STATE_GOTO(EVAL_AB, st->u.eval.prev_eval->u.eval.B,
+                PUSH_YES_STATE_GOTO(EVAL_postponed_AB, st->u.eval.prev_eval->u.eval.B,
                                     locinput); /* match B */
            }
 
@@ -8155,7 +8631,7 @@ NULL
                 sv_commit = ST.mark_name;
 
                 DEBUG_EXECUTE_r({
-                        Perl_re_exec_indentf( aTHX_  "%ssetting cutpoint to mark:%"SVf"...%s\n",
+                        Perl_re_exec_indentf( aTHX_  "%ssetting cutpoint to mark:%" SVf "...%s\n",
                             depth,
                            PL_colors[4], SVfARG(sv_commit), PL_colors[5]);
                });
@@ -8220,7 +8696,7 @@ NULL
             break;
 
        default:
-           PerlIO_printf(Perl_error_log, "%"UVxf" %d\n",
+           PerlIO_printf(Perl_error_log, "%" UVxf " %d\n",
                          PTR2UV(scan), OP(scan));
            Perl_croak(aTHX_ "regexp memory corruption");
 
@@ -8230,7 +8706,8 @@ NULL
             assert(!NEXTCHR_IS_EOS);
             if (utf8_target) {
                 locinput += PL_utf8skip[nextchr];
-                /* locinput is allowed to go 1 char off the end, but not 2+ */
+                /* locinput is allowed to go 1 char off the end (signifying
+                 * EOS), but not 2+ */
                 if (locinput > reginfo->strend)
                     sayNO;
             }
@@ -8258,16 +8735,17 @@ NULL
            DEBUG_STACK_r({
                regmatch_state *cur = st;
                regmatch_state *curyes = yes_state;
-               int curd = depth;
+               U32 i;
                regmatch_slab *slab = PL_regmatch_slab;
-                for (;curd > -1 && (depth-curd < 3);cur--,curd--) {
+                for (i = 0; i < 3 && i <= depth; cur--,i++) {
                     if (cur < SLAB_FIRST(slab)) {
                        slab = slab->prev;
                        cur = SLAB_LAST(slab);
                     }
-                    Perl_re_exec_indentf( aTHX_ "#%-3d %-10s %s\n",
+                    Perl_re_exec_indentf( aTHX_ "%4s #%-3d %-10s %s\n",
                         depth,
-                        curd, PL_reg_name[cur->resume_state],
+                        i ? "    " : "push",
+                        depth - i, PL_reg_name[cur->resume_state],
                         (curyes == cur) ? "yes" : ""
                     );
                     if (curyes == cur)
@@ -8289,6 +8767,9 @@ NULL
             /* NOTREACHED */
        }
     }
+#ifdef SOLARIS_BAD_OPTIMIZER
+#  undef PL_charclass
+#endif
 
     /*
     * We get here only if there's trouble -- normally "case END" is
@@ -8389,6 +8870,7 @@ NULL
            yes_state = st->u.yes.prev_yes_state;
 
        state_num = st->resume_state + 1; /* failure = success + 1 */
+        PERL_ASYNC_CHECK();
        goto reenter_switch;
     }
     result = 0;
@@ -8415,9 +8897,12 @@ NULL
 
     if (last_pushed_cv) {
        dSP;
+        /* see "Some notes about MULTICALL" above */
        POP_MULTICALL;
         PERL_UNUSED_VAR(SP);
     }
+    else
+        LEAVE_SCOPE(orig_savestack_ix);
 
     assert(!result ||  locinput - reginfo->strbeg >= 0);
     return result ?  locinput - reginfo->strbeg : -1;
@@ -8439,7 +8924,7 @@ NULL
  */
 STATIC I32
 S_regrepeat(pTHX_ regexp *prog, char **startposp, const regnode *p,
-            regmatch_info *const reginfo, I32 max, int depth)
+            regmatch_info *const reginfo, I32 max _pDEPTH)
 {
     char *scan;     /* Pointer to current position in target string */
     I32 c;
@@ -8449,9 +8934,6 @@ S_regrepeat(pTHX_ regexp *prog, char **startposp, const regnode *p,
     unsigned int to_complement = 0;  /* Invert the result? */
     UV utf8_flags;
     _char_class_number classnum;
-#ifndef DEBUGGING
-    PERL_UNUSED_ARG(depth);
-#endif
 
     PERL_ARGS_ASSERT_REGREPEAT;
 
@@ -8656,10 +9138,27 @@ S_regrepeat(pTHX_ regexp *prog, char **startposp, const regnode *p,
                 }
             }
             else {
-                while (scan < loceol &&
-                    (UCHARAT(scan) == c1 || UCHARAT(scan) == c2))
-                {
-                    scan++;
+                /* See comments in regmatch() CURLY_B_min_known_fail.  We avoid
+                 * a conditional each time through the loop if the characters
+                 * differ only in a single bit, as is the usual situation */
+                U8 c1_c2_bits_differing = c1 ^ c2;
+
+                if (isPOWER_OF_2(c1_c2_bits_differing)) {
+                    U8 c1_masked = c1 & ~ c1_c2_bits_differing;
+                    U8 c1_c2_mask = ~ c1_c2_bits_differing;
+
+                    while (   scan < loceol
+                           && (UCHARAT(scan) & c1_c2_mask) == c1_masked)
+                    {
+                        scan++;
+                    }
+                }
+                else {
+                    while (    scan < loceol
+                           && (UCHARAT(scan) == c1 || UCHARAT(scan) == c2))
+                    {
+                        scan++;
+                    }
                 }
             }
        }
@@ -8682,12 +9181,45 @@ S_regrepeat(pTHX_ regexp *prog, char **startposp, const regnode *p,
                scan += UTF8SKIP(scan);
                hardcount++;
            }
-       } else {
-           while (scan < loceol && REGINCLASS(prog, p, (U8*)scan, 0))
+       }
+        else if (ANYOF_FLAGS(p)) {
+           while (scan < loceol
+                    && reginclass(prog, p, (U8*)scan, (U8*)scan+1, 0))
+               scan++;
+        }
+        else {
+           while (scan < loceol && ANYOF_BITMAP_TEST(p, *((U8*)scan)))
                scan++;
        }
        break;
 
+    case ASCII:
+        if (utf8_target && loceol - scan > max) {
+
+            /* We didn't adjust <loceol> at the beginning of this routine
+             * because is UTF-8, but it is actually ok to do so, since here, to
+             * match, 1 char == 1 byte. */
+            loceol = scan + max;
+        }
+
+        scan = find_next_non_ascii(scan, loceol, utf8_target);
+       break;
+
+    case NASCII:
+       if (utf8_target) {
+           while (     hardcount < max
+                   &&   scan < loceol
+                  && ! isASCII_utf8_safe(scan, loceol))
+           {
+               scan += UTF8SKIP(scan);
+               hardcount++;
+           }
+       }
+        else {
+            scan = find_next_ascii(scan, loceol, utf8_target);
+       }
+       break;
+
     /* The argument (FLAGS) to all the POSIX node types is the class number */
 
     case NPOSIXL:
@@ -8750,7 +9282,7 @@ S_regrepeat(pTHX_ regexp *prog, char **startposp, const regnode *p,
             /* The complement of something that matches only ASCII matches all
              * non-ASCII, plus everything in ASCII that isn't in the class. */
            while (hardcount < max && scan < loceol
-                   && (! isASCII_utf8(scan)
+                   && (   ! isASCII_utf8_safe(scan, reginfo->strend)
                        || ! _generic_isCC_A((U8) *scan, FLAGS(p))))
             {
                 scan += UTF8SKIP(scan);
@@ -8818,7 +9350,8 @@ S_regrepeat(pTHX_ regexp *prog, char **startposp, const regnode *p,
                     case _CC_ENUM_SPACE:
                         while (hardcount < max
                                && scan < loceol
-                               && (to_complement ^ cBOOL(isSPACE_utf8(scan))))
+                               && (to_complement
+                                   ^ cBOOL(isSPACE_utf8_safe(scan, loceol))))
                         {
                             scan += UTF8SKIP(scan);
                             hardcount++;
@@ -8827,7 +9360,8 @@ S_regrepeat(pTHX_ regexp *prog, char **startposp, const regnode *p,
                     case _CC_ENUM_BLANK:
                         while (hardcount < max
                                && scan < loceol
-                               && (to_complement ^ cBOOL(isBLANK_utf8(scan))))
+                               && (to_complement
+                                    ^ cBOOL(isBLANK_utf8_safe(scan, loceol))))
                         {
                             scan += UTF8SKIP(scan);
                             hardcount++;
@@ -8836,7 +9370,8 @@ S_regrepeat(pTHX_ regexp *prog, char **startposp, const regnode *p,
                     case _CC_ENUM_XDIGIT:
                         while (hardcount < max
                                && scan < loceol
-                               && (to_complement ^ cBOOL(isXDIGIT_utf8(scan))))
+                               && (to_complement
+                                   ^ cBOOL(isXDIGIT_utf8_safe(scan, loceol))))
                         {
                             scan += UTF8SKIP(scan);
                             hardcount++;
@@ -8845,7 +9380,8 @@ S_regrepeat(pTHX_ regexp *prog, char **startposp, const regnode *p,
                     case _CC_ENUM_VERTSPACE:
                         while (hardcount < max
                                && scan < loceol
-                               && (to_complement ^ cBOOL(isVERTWS_utf8(scan))))
+                               && (to_complement
+                                   ^ cBOOL(isVERTWS_utf8_safe(scan, loceol))))
                         {
                             scan += UTF8SKIP(scan);
                             hardcount++;
@@ -8854,7 +9390,8 @@ S_regrepeat(pTHX_ regexp *prog, char **startposp, const regnode *p,
                     case _CC_ENUM_CNTRL:
                         while (hardcount < max
                                && scan < loceol
-                               && (to_complement ^ cBOOL(isCNTRL_utf8(scan))))
+                               && (to_complement
+                                   ^ cBOOL(isCNTRL_utf8_safe(scan, loceol))))
                         {
                             scan += UTF8SKIP(scan);
                             hardcount++;
@@ -8880,9 +9417,10 @@ S_regrepeat(pTHX_ regexp *prog, char **startposp, const regnode *p,
         }
 
         while (hardcount < max && scan < loceol
-               && to_complement ^ cBOOL(_generic_utf8(
+               && to_complement ^ cBOOL(_generic_utf8_safe(
                                        classnum,
                                        scan,
+                                       loceol,
                                        swash_fetch(PL_utf8_swash_ptrs[classnum],
                                                    (U8 *) scan,
                                                    TRUE))))
@@ -8947,7 +9485,7 @@ S_regrepeat(pTHX_ regexp *prog, char **startposp, const regnode *p,
        DEBUG_EXECUTE_r({
            SV * const prop = sv_newmortal();
             regprop(prog, prop, p, reginfo, NULL);
-            Perl_re_exec_indentf( aTHX_  "%s can match %"IVdf" times out of %"IVdf"...\n",
+            Perl_re_exec_indentf( aTHX_  "%s can match %" IVdf " times out of %" IVdf "...\n",
                         depth, SvPVX_const(prop),(IV)c,(IV)max);
        });
     });
@@ -9006,13 +9544,14 @@ S_reginclass(pTHX_ regexp * const prog, const regnode * const n, const U8* const
      * UTF8_IS_INVARIANT() works even if not in UTF-8 */
     if (! UTF8_IS_INVARIANT(c) && utf8_target) {
         STRLEN c_len = 0;
-       c = utf8n_to_uvchr(p, p_end - p, &c_len,
-               (UTF8_ALLOW_DEFAULT & UTF8_ALLOW_ANYUV)
-               | UTF8_ALLOW_FFFF | UTF8_CHECK_ONLY);
-               /* see [perl #37836] for UTF8_ALLOW_ANYUV; [perl #38293] for
-                * UTF8_ALLOW_FFFF */
-       if (c_len == (STRLEN)-1)
-           Perl_croak(aTHX_ "Malformed UTF-8 character (fatal)");
+        const U32 utf8n_flags = UTF8_ALLOW_DEFAULT;
+       c = utf8n_to_uvchr(p, p_end - p, &c_len, utf8n_flags | UTF8_CHECK_ONLY);
+       if (c_len == (STRLEN)-1) {
+            _force_out_malformed_utf8_message(p, p_end,
+                                              utf8n_flags,
+                                              1 /* 1 means die */ );
+            NOT_REACHED; /* NOTREACHED */
+        }
         if (c > 255 && OP(n) == ANYOFL && ! ANYOFL_UTF8_LOCALE_REQD(flags)) {
             _CHECK_AND_OUTPUT_WIDE_LOCALE_CP_MSG(c);
         }
@@ -9149,7 +9688,7 @@ S_reginclass(pTHX_ regexp * const prog, const regnode * const n, const U8* const
             && ckWARN_d(WARN_NON_UNICODE))
         {
             Perl_warner(aTHX_ packWARN(WARN_NON_UNICODE),
-                "Matched non-Unicode code point 0x%04"UVXf" against Unicode property; may not be portable", c);
+                "Matched non-Unicode code point 0x%04" UVXf " against Unicode property; may not be portable", c);
         }
     }
 
@@ -9175,7 +9714,10 @@ S_reghop3(U8 *s, SSize_t off, const U8* lim)
     if (off >= 0) {
        while (off-- && s < lim) {
            /* XXX could check well-formedness here */
-           s += UTF8SKIP(s);
+           U8 *new_s = s + UTF8SKIP(s);
+            if (new_s > lim) /* lim may be in the middle of a long character */
+                return s;
+            s = new_s;
        }
     }
     else {
@@ -9225,7 +9767,7 @@ S_reghop4(U8 *s, SSize_t off, const U8* llim, const U8* rlim)
  * char pos */
 
 STATIC U8 *
-S_reghopmaybe3(U8* s, SSize_t off, const U8* lim)
+S_reghopmaybe3(U8* s, SSize_t off, const U8* const lim)
 {
     PERL_ARGS_ASSERT_REGHOPMAYBE3;
 
@@ -9318,6 +9860,7 @@ S_setup_eval_state(pTHX_ regmatch_info *const reginfo)
     }
     SET_reg_curpm(reginfo->prog);
     eval_state->curpm = PL_curpm;
+    PL_curpm_under = PL_curpm;
     PL_curpm = PL_reg_curpm;
     if (RXp_MATCH_COPIED(rex)) {
         /*  Here is a serious problem: we cannot rewrite subbeg,
@@ -9466,6 +10009,434 @@ S_to_byte_substr(pTHX_ regexp *prog)
     return TRUE;
 }
 
+#ifndef PERL_IN_XSUB_RE
+
+bool
+Perl__is_grapheme(pTHX_ const U8 * strbeg, const U8 * s, const U8 * strend, const UV cp)
+{
+    /* Temporary helper function for toke.c.  Verify that the code point 'cp'
+     * is a stand-alone grapheme.  The UTF-8 for 'cp' begins at position 's' in
+     * the larger string bounded by 'strbeg' and 'strend'.
+     *
+     * 'cp' needs to be assigned (if not a future version of the Unicode
+     * Standard could make it something that combines with adjacent characters,
+     * so code using it would then break), and there has to be a GCB break
+     * before and after the character. */
+
+    GCB_enum cp_gcb_val, prev_cp_gcb_val, next_cp_gcb_val;
+    const U8 * prev_cp_start;
+
+    PERL_ARGS_ASSERT__IS_GRAPHEME;
+
+    /* Unassigned code points are forbidden */
+    if (UNLIKELY(! ELEMENT_RANGE_MATCHES_INVLIST(
+                                    _invlist_search(PL_Assigned_invlist, cp))))
+    {
+        return FALSE;
+    }
+
+    cp_gcb_val = getGCB_VAL_CP(cp);
+
+    /* Find the GCB value of the previous code point in the input */
+    prev_cp_start = utf8_hop_back(s, -1, strbeg);
+    if (UNLIKELY(prev_cp_start == s)) {
+        prev_cp_gcb_val = GCB_EDGE;
+    }
+    else {
+        prev_cp_gcb_val = getGCB_VAL_UTF8(prev_cp_start, strend);
+    }
+
+    /* And check that is a grapheme boundary */
+    if (! isGCB(prev_cp_gcb_val, cp_gcb_val, strbeg, s,
+                TRUE /* is UTF-8 encoded */ ))
+    {
+        return FALSE;
+    }
+
+    /* Similarly verify there is a break between the current character and the
+     * following one */
+    s += UTF8SKIP(s);
+    if (s >= strend) {
+        next_cp_gcb_val = GCB_EDGE;
+    }
+    else {
+        next_cp_gcb_val = getGCB_VAL_UTF8(s, strend);
+    }
+
+    return isGCB(cp_gcb_val, next_cp_gcb_val, strbeg, s, TRUE);
+}
+
+#endif
+
+bool
+Perl_isSCRIPT_RUN(pTHX_ const U8 * s, const U8 * send, const bool utf8_target)
+{
+    /* Checks that every character in the sequence from 's' to 'send' is one of
+     * three scripts: Common, Inherited, and possibly one other.  Additionally
+     * all decimal digits must come from the same consecutive sequence of 10.
+     * 'utf8_target' is TRUE iff the sequence is encoded in UTF-8.
+     *
+     * Basically, it looks at each character in the sequence to see if the
+     * above conditions are met; if not it fails.  It uses an inversion map to
+     * find the enum corresponding to the script of each character.  But this
+     * is complicated by the fact that a few code points can be in any of
+     * several scripts.  The data has been constructed so that there are
+     * additional enum values (all negative) for these situations.  The
+     * absolute value of those is an index into another table which contains
+     * pointers to auxiliary tables for each such situation.  Each aux array
+     * lists all the scripts for the given situation.  There is another,
+     * parallel, table that gives the number of entries in each aux table.
+     * These are all defined in charclass_invlists.h */
+
+    /* XXX Here are the additional things UTS 39 says could be done:
+     * Mark Chinese strings as “mixed script” if they contain both simplified
+     * (S) and traditional (T) Chinese characters, using the Unihan data in the
+     * Unicode Character Database [UCD].  The criterion can only be applied if
+     * the language of the string is known to be Chinese. So, for example, the
+     * string “写真だけの結婚式 ” is Japanese, and should not be marked as
+     * mixed script because of a mixture of S and T characters.  Testing for
+     * whether a character is S or T needs to be based not on whether the
+     * character has a S or T variant , but whether the character is an S or T
+     * variant. khw notes that the sample contains a Hiragana character, and it
+     * is unclear if absence of any foreign script marks the script as
+     * "Chinese"
+     *
+     * Forbid sequences of the same nonspacing mark
+     *
+     * Check to see that all the characters are in the sets of exemplar
+     * characters for at least one language in the Unicode Common Locale Data
+     * Repository [CLDR]. */
+
+
+    /* Things that match /\d/u */
+    SV * decimals_invlist = PL_XPosix_ptrs[_CC_DIGIT];
+    UV * decimals_array = invlist_array(decimals_invlist);
+
+    /* What code point is the digit '0' of the script run? */
+    UV zero_of_run = 0;
+    SCX_enum script_of_run  = SCX_INVALID;   /* Illegal value */
+    SCX_enum script_of_char = SCX_INVALID;
+
+    /* If the script remains not fully determined from iteration to iteration,
+     * this is the current intersection of the possiblities.  */
+    SCX_enum * intersection = NULL;
+    PERL_UINT_FAST8_T intersection_len = 0;
+
+    bool retval = TRUE;
+
+    assert(send > s);
+
+    PERL_ARGS_ASSERT_ISSCRIPT_RUN;
+
+    /* Look at each character in the sequence */
+    while (s < send) {
+        UV cp;
+
+        /* The code allows all scripts to use the ASCII digits.  This is
+         * because they are used in commerce even in scripts that have their
+         * own set.  Hence any ASCII ones found are ok, unless a digit from
+         * another set has already been encountered.  (The other digit ranges
+         * in Common are not similarly blessed */
+        if (UNLIKELY(isDIGIT(*s))) {
+            if (zero_of_run > 0) {
+                if (zero_of_run != '0') {
+                    retval = FALSE;
+                    break;
+                }
+            }
+            else {
+                zero_of_run = '0';
+            }
+            s++;
+            continue;
+        }
+
+        /* Here, isn't an ASCII digit.  Find the code point of the character */
+        if (utf8_target && ! UTF8_IS_INVARIANT(*s)) {
+            Size_t len;
+            cp = valid_utf8_to_uvchr((U8 *) s, &len);
+            s += len;
+        }
+        else {
+            cp = *(s++);
+        }
+
+        /* If is within the range [+0 .. +9] of the script's zero, it also is a
+         * digit in that script.  We can skip the rest of this code for this
+         * character. */
+        if (UNLIKELY(   zero_of_run > 0
+                     && cp >= zero_of_run
+                     && cp - zero_of_run <= 9))
+        {
+            continue;
+        }
+
+        /* Find the character's script.  The correct values are hard-coded here
+         * for small-enough code points. */
+        if (cp < 0x2B9) {   /* From inspection of Unicode db; extremely
+                               unlikely to change */
+            if (       cp > 255
+                || (   isALPHA_L1(cp)
+                    && LIKELY(cp != MICRO_SIGN_NATIVE)))
+            {
+                script_of_char = SCX_Latin;
+            }
+            else {
+                script_of_char = SCX_Common;
+            }
+        }
+        else {
+            script_of_char = _Perl_SCX_invmap[
+                                       _invlist_search(PL_SCX_invlist, cp)];
+        }
+
+        /* We arbitrarily accept a single unassigned character, but not in
+         * combination with anything else, and not a run of them. */
+        if (   UNLIKELY(script_of_run == SCX_Unknown)
+            || UNLIKELY(   script_of_run != SCX_INVALID
+                        && script_of_char == SCX_Unknown))
+        {
+            retval = FALSE;
+            break;
+        }
+
+        if (UNLIKELY(script_of_char == SCX_Unknown)) {
+                script_of_run = SCX_Unknown;
+                continue;
+        }
+
+        /* We accept 'inherited' script characters currently even at the
+         * beginning.  (We know that no characters in Inherited are digits, or
+         * we'd have to check for that) */
+        if (UNLIKELY(script_of_char == SCX_Inherited)) {
+            continue;
+        }
+
+        /* If unknown, the run's script is set to the char's */
+        if (UNLIKELY(script_of_run == SCX_INVALID)) {
+            script_of_run = script_of_char;
+        }
+
+        /* All decimal digits must be from the same sequence of 10.  Above, we
+         * handled any ASCII digits without descending to here.  We also
+         * handled the case where we already knew what digit sequence is the
+         * one to use, and the character is in that sequence.  Now that we know
+         * the script, we can use script_zeros[] to directly find which
+         * sequence the script uses, except in a few cases it returns 0 */
+        if (UNLIKELY(zero_of_run == 0) && script_of_char >= 0) {
+            zero_of_run = script_zeros[script_of_char];
+        }
+
+        /* Now we can see if the script of the character is the same as that of
+         * the run */
+        if (LIKELY(script_of_char == script_of_run)) {
+            /* By far the most common case */
+            goto scripts_match;
+        }
+
+        /* Here, the scripts of the run and the current character don't match
+         * exactly.  The run could so far have been entirely characters from
+         * Common.  It's now time to change its script to that of this
+         * non-Common character */
+        if (script_of_run == SCX_Common) {
+
+            /* But Common contains several sets of digits.  Only the '0' set
+             * can be part of another script. */
+            if (zero_of_run > 0 && zero_of_run != '0') {
+                retval = FALSE;
+                break;
+            }
+
+            script_of_run = script_of_char;
+            goto scripts_match;
+        }
+
+        /* Here, the script of the run isn't Common.  But characters in Common
+         * match any script */
+        if (script_of_char == SCX_Common) {
+            goto scripts_match;
+        }
+
+#ifndef HAS_SCX_AUX_TABLES
+
+        /* Too early a Unicode version to have a code point belonging to more
+         * than one script, so, if the scripts don't exactly match, fail */
+        retval = FALSE;
+        break;
+
+#else
+
+        /* Here there is no exact match between the character's script and the
+         * run's.  And we've handled the special cases of scripts Unknown,
+         * Inherited, and Common.
+         *
+         * Negative script numbers signify that the value may be any of several
+         * scripts, and we need to look at auxiliary information to make our
+         * deterimination.  But if both are non-negative, we can fail now */
+        if (LIKELY(script_of_char >= 0)) {
+            const SCX_enum * search_in;
+            PERL_UINT_FAST8_T search_in_len;
+            PERL_UINT_FAST8_T i;
+
+            if (LIKELY(script_of_run >= 0)) {
+                retval = FALSE;
+                break;
+            }
+
+            /* Use the previously constructed set of possible scripts, if any.
+             * */
+            if (intersection) {
+                search_in = intersection;
+                search_in_len = intersection_len;
+            }
+            else {
+                search_in = SCX_AUX_TABLE_ptrs[-script_of_run];
+                search_in_len = SCX_AUX_TABLE_lengths[-script_of_run];
+            }
+
+            for (i = 0; i < search_in_len; i++) {
+                if (search_in[i] == script_of_char) {
+                    script_of_run = script_of_char;
+                    goto scripts_match;
+                }
+            }
+
+            retval = FALSE;
+            break;
+        }
+        else if (LIKELY(script_of_run >= 0)) {
+            /* script of character could be one of several, but run is a single
+             * script */
+            const SCX_enum * search_in = SCX_AUX_TABLE_ptrs[-script_of_char];
+            const PERL_UINT_FAST8_T search_in_len
+                                     = SCX_AUX_TABLE_lengths[-script_of_char];
+            PERL_UINT_FAST8_T i;
+
+            for (i = 0; i < search_in_len; i++) {
+                if (search_in[i] == script_of_run) {
+                    script_of_char = script_of_run;
+                    goto scripts_match;
+                }
+            }
+
+            retval = FALSE;
+            break;
+        }
+        else {
+            /* Both run and char could be in one of several scripts.  If the
+             * intersection is empty, then this character isn't in this script
+             * run.  Otherwise, we need to calculate the intersection to use
+             * for future iterations of the loop, unless we are already at the
+             * final character */
+            const SCX_enum * search_char = SCX_AUX_TABLE_ptrs[-script_of_char];
+            const PERL_UINT_FAST8_T char_len
+                                      = SCX_AUX_TABLE_lengths[-script_of_char];
+            const SCX_enum * search_run;
+            PERL_UINT_FAST8_T run_len;
+
+            SCX_enum * new_overlap = NULL;
+            PERL_UINT_FAST8_T i, j;
+
+            if (intersection) {
+                search_run = intersection;
+                run_len = intersection_len;
+            }
+            else {
+                search_run = SCX_AUX_TABLE_ptrs[-script_of_run];
+                run_len = SCX_AUX_TABLE_lengths[-script_of_run];
+            }
+
+            intersection_len = 0;
+
+            for (i = 0; i < run_len; i++) {
+                for (j = 0; j < char_len; j++) {
+                    if (search_run[i] == search_char[j]) {
+
+                        /* Here, the script at i,j matches.  That means this
+                         * character is in the run.  But continue on to find
+                         * the complete intersection, for the next loop
+                         * iteration, and for the digit check after it.
+                         *
+                         * On the first found common script, we malloc space
+                         * for the intersection list for the worst case of the
+                         * intersection, which is the minimum of the number of
+                         * scripts remaining in each set. */
+                        if (intersection_len == 0) {
+                            Newx(new_overlap,
+                                 MIN(run_len - i, char_len - j),
+                                 SCX_enum);
+                        }
+                        new_overlap[intersection_len++] = search_run[i];
+                    }
+                }
+            }
+
+            /* Here we've looked through everything.  If they have no scripts
+             * in common, not a run */
+            if (intersection_len == 0) {
+                retval = FALSE;
+                break;
+            }
+
+            /* If there is only a single script in common, set to that.
+             * Otherwise, use the intersection going forward */
+            Safefree(intersection);
+            if (intersection_len == 1) {
+                script_of_run = script_of_char = new_overlap[0];
+                Safefree(new_overlap);
+            }
+            else {
+                intersection = new_overlap;
+            }
+        }
+
+#endif
+
+  scripts_match: ;
+
+        /* Here, the script of the character is compatible with that of the
+         * run.  Either they match exactly, or one or both can be any of
+         * several scripts, and the intersection is not empty.  If the
+         * character is not a decimal digit, we are done with it.  Otherwise,
+         * it could still fail if it is from a different set of 10 than seen
+         * already (or we may not have seen any, and we need to set the
+         * sequence).  If we have determined a single script and that script
+         * only has one set of digits (almost all scripts are like that), then
+         * this isn't a problem, as any digit must come from the same sequence.
+         * The only scripts that have multiple sequences have been constructed
+         * to be 0 in 'script_zeros[]'.
+         *
+         * Here we check if it is a digit. */
+        if (    cp >= FIRST_NON_ASCII_DECIMAL_DIGIT
+            && (   (          zero_of_run == 0
+                    || (  (   script_of_char >= 0
+                           && script_zeros[script_of_char] == 0)
+                        ||    intersection))))
+        {
+            SSize_t range_zero_index;
+            range_zero_index = _invlist_search(decimals_invlist, cp);
+            if (   LIKELY(range_zero_index >= 0)
+                && ELEMENT_RANGE_MATCHES_INVLIST(range_zero_index))
+            {
+                UV range_zero = decimals_array[range_zero_index];
+                if (zero_of_run) {
+                    if (zero_of_run != range_zero) {
+                        retval = FALSE;
+                        break;
+                    }
+                }
+                else {
+                    zero_of_run = range_zero;
+                }
+            }
+        }
+    } /* end of looping through CLOSESR text */
+
+    Safefree(intersection);
+    return retval;
+}
+
+
 /*
  * ex: set ts=8 sts=4 sw=4 et:
  */