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regmatch(): make IFMATCH use PUSH_STACK rather than fake recursion
[perl5.git] / regexec.c
index 4aa27f8..890736c 100644 (file)
--- a/regexec.c
+++ b/regexec.c
@@ -839,7 +839,7 @@ Perl_re_intuit_start(pTHX_ regexp *prog, SV *sv, char *strpos,
                   : strend);
 
        t = s;
-        s = find_byclass(prog, prog->regstclass, s, endpos, 1);
+        s = find_byclass(prog, prog->regstclass, s, endpos, NULL);
        if (!s) {
 #ifdef DEBUGGING
            const char *what = NULL;
@@ -931,8 +931,11 @@ Perl_re_intuit_start(pTHX_ regexp *prog, SV *sv, char *strpos,
 }
 
 /* We know what class REx starts with.  Try to find this position... */
+/* if reginfo is NULL, its a dryrun */
+
 STATIC char *
-S_find_byclass(pTHX_ regexp * prog, const regnode *c, char *s, const char *strend, I32 norun)
+S_find_byclass(pTHX_ regexp * prog, const regnode *c, char *s, const char
+*strend, const regmatch_info *reginfo)
 {
        dVAR;
        const I32 doevery = (prog->reganch & ROPT_SKIP) == 0;
@@ -955,7 +958,7 @@ S_find_byclass(pTHX_ regexp * prog, const regnode *c, char *s, const char *stren
                          !UTF8_IS_INVARIANT((U8)s[0]) ?
                          reginclass(prog, c, (U8*)s, 0, do_utf8) :
                          REGINCLASS(prog, c, (U8*)s)) {
-                          if (tmp && (norun || regtry(prog, s)))
+                          if (tmp && (!reginfo || regtry(reginfo, s)))
                                goto got_it;
                           else
                                tmp = doevery;
@@ -974,7 +977,7 @@ S_find_byclass(pTHX_ regexp * prog, const regnode *c, char *s, const char *stren
                           /* The assignment of 2 is intentional:
                            * for the folded sharp s, the skip is 2. */
                           (skip = SHARP_S_SKIP))) {
-                          if (tmp && (norun || regtry(prog, s)))
+                          if (tmp && (!reginfo || regtry(reginfo, s)))
                                goto got_it;
                           else
                                tmp = doevery;
@@ -987,7 +990,7 @@ S_find_byclass(pTHX_ regexp * prog, const regnode *c, char *s, const char *stren
            break;
        case CANY:
            while (s < strend) {
-               if (tmp && (norun || regtry(prog, s)))
+               if (tmp && (!reginfo || regtry(reginfo, s)))
                    goto got_it;
                else
                    tmp = doevery;
@@ -1032,7 +1035,7 @@ S_find_byclass(pTHX_ regexp * prog, const regnode *c, char *s, const char *stren
          do_exactf:
            e = HOP3c(strend, -((I32)lnc), s);
 
-           if (norun && e < s)
+           if (!reginfo && e < s)
                e = s;                  /* Due to minlen logic of intuit() */
 
            /* The idea in the EXACTF* cases is to first find the
@@ -1061,7 +1064,7 @@ S_find_byclass(pTHX_ regexp * prog, const regnode *c, char *s, const char *stren
                             && (ln == len ||
                                 ibcmp_utf8(s, (char **)0, 0,  do_utf8,
                                            m, (char **)0, ln, (bool)UTF))
-                            && (norun || regtry(prog, s)) )
+                            && (!reginfo || regtry(reginfo, s)) )
                            goto got_it;
                        else {
                             U8 foldbuf[UTF8_MAXBYTES_CASE+1];
@@ -1074,7 +1077,7 @@ S_find_byclass(pTHX_ regexp * prog, const regnode *c, char *s, const char *stren
                                                  (char **)0, foldlen, do_utf8,
                                                  m,
                                                  (char **)0, ln, (bool)UTF))
-                                 && (norun || regtry(prog, s)) )
+                                 && (!reginfo || regtry(reginfo, s)) )
                                  goto got_it;
                        }
                        s += len;
@@ -1100,7 +1103,7 @@ S_find_byclass(pTHX_ regexp * prog, const regnode *c, char *s, const char *stren
                             && (ln == len ||
                                 ibcmp_utf8(s, (char **)0, 0,  do_utf8,
                                            m, (char **)0, ln, (bool)UTF))
-                            && (norun || regtry(prog, s)) )
+                            && (!reginfo || regtry(reginfo, s)) )
                            goto got_it;
                        else {
                             U8 foldbuf[UTF8_MAXBYTES_CASE+1];
@@ -1113,7 +1116,7 @@ S_find_byclass(pTHX_ regexp * prog, const regnode *c, char *s, const char *stren
                                                  (char **)0, foldlen, do_utf8,
                                                  m,
                                                  (char **)0, ln, (bool)UTF))
-                                 && (norun || regtry(prog, s)) )
+                                 && (!reginfo || regtry(reginfo, s)) )
                                  goto got_it;
                        }
                        s += len;
@@ -1127,7 +1130,7 @@ S_find_byclass(pTHX_ regexp * prog, const regnode *c, char *s, const char *stren
                             && (ln == 1 || !(OP(c) == EXACTF
                                              ? ibcmp(s, m, ln)
                                              : ibcmp_locale(s, m, ln)))
-                            && (norun || regtry(prog, s)) )
+                            && (!reginfo || regtry(reginfo, s)) )
                            goto got_it;
                        s++;
                    }
@@ -1137,7 +1140,7 @@ S_find_byclass(pTHX_ regexp * prog, const regnode *c, char *s, const char *stren
                             && (ln == 1 || !(OP(c) == EXACTF
                                              ? ibcmp(s, m, ln)
                                              : ibcmp_locale(s, m, ln)))
-                            && (norun || regtry(prog, s)) )
+                            && (!reginfo || regtry(reginfo, s)) )
                            goto got_it;
                        s++;
                    }
@@ -1163,7 +1166,7 @@ S_find_byclass(pTHX_ regexp * prog, const regnode *c, char *s, const char *stren
                                 isALNUM_LC_utf8((U8*)s)))
                    {
                        tmp = !tmp;
-                       if ((norun || regtry(prog, s)))
+                       if ((!reginfo || regtry(reginfo, s)))
                            goto got_it;
                    }
                    s += uskip;
@@ -1176,13 +1179,13 @@ S_find_byclass(pTHX_ regexp * prog, const regnode *c, char *s, const char *stren
                    if (tmp ==
                        !(OP(c) == BOUND ? isALNUM(*s) : isALNUM_LC(*s))) {
                        tmp = !tmp;
-                       if ((norun || regtry(prog, s)))
+                       if ((!reginfo || regtry(reginfo, s)))
                            goto got_it;
                    }
                    s++;
                }
            }
-           if ((!prog->minlen && tmp) && (norun || regtry(prog, s)))
+           if ((!prog->minlen && tmp) && (!reginfo || regtry(reginfo, s)))
                goto got_it;
            break;
        case NBOUNDL:
@@ -1204,7 +1207,7 @@ S_find_byclass(pTHX_ regexp * prog, const regnode *c, char *s, const char *stren
                                 swash_fetch(PL_utf8_alnum, (U8*)s, do_utf8) :
                                 isALNUM_LC_utf8((U8*)s)))
                        tmp = !tmp;
-                   else if ((norun || regtry(prog, s)))
+                   else if ((!reginfo || regtry(reginfo, s)))
                        goto got_it;
                    s += uskip;
                }
@@ -1217,12 +1220,12 @@ S_find_byclass(pTHX_ regexp * prog, const regnode *c, char *s, const char *stren
                    if (tmp ==
                        !(OP(c) == NBOUND ? isALNUM(*s) : isALNUM_LC(*s)))
                        tmp = !tmp;
-                   else if ((norun || regtry(prog, s)))
+                   else if ((!reginfo || regtry(reginfo, s)))
                        goto got_it;
                    s++;
                }
            }
-           if ((!prog->minlen && !tmp) && (norun || regtry(prog, s)))
+           if ((!prog->minlen && !tmp) && (!reginfo || regtry(reginfo, s)))
                goto got_it;
            break;
        case ALNUM:
@@ -1230,7 +1233,7 @@ S_find_byclass(pTHX_ regexp * prog, const regnode *c, char *s, const char *stren
                LOAD_UTF8_CHARCLASS_ALNUM();
                while (s + (uskip = UTF8SKIP(s)) <= strend) {
                    if (swash_fetch(PL_utf8_alnum, (U8*)s, do_utf8)) {
-                       if (tmp && (norun || regtry(prog, s)))
+                       if (tmp && (!reginfo || regtry(reginfo, s)))
                            goto got_it;
                        else
                            tmp = doevery;
@@ -1243,7 +1246,7 @@ S_find_byclass(pTHX_ regexp * prog, const regnode *c, char *s, const char *stren
            else {
                while (s < strend) {
                    if (isALNUM(*s)) {
-                       if (tmp && (norun || regtry(prog, s)))
+                       if (tmp && (!reginfo || regtry(reginfo, s)))
                            goto got_it;
                        else
                            tmp = doevery;
@@ -1259,7 +1262,7 @@ S_find_byclass(pTHX_ regexp * prog, const regnode *c, char *s, const char *stren
            if (do_utf8) {
                while (s + (uskip = UTF8SKIP(s)) <= strend) {
                    if (isALNUM_LC_utf8((U8*)s)) {
-                       if (tmp && (norun || regtry(prog, s)))
+                       if (tmp && (!reginfo || regtry(reginfo, s)))
                            goto got_it;
                        else
                            tmp = doevery;
@@ -1272,7 +1275,7 @@ S_find_byclass(pTHX_ regexp * prog, const regnode *c, char *s, const char *stren
            else {
                while (s < strend) {
                    if (isALNUM_LC(*s)) {
-                       if (tmp && (norun || regtry(prog, s)))
+                       if (tmp && (!reginfo || regtry(reginfo, s)))
                            goto got_it;
                        else
                            tmp = doevery;
@@ -1288,7 +1291,7 @@ S_find_byclass(pTHX_ regexp * prog, const regnode *c, char *s, const char *stren
                LOAD_UTF8_CHARCLASS_ALNUM();
                while (s + (uskip = UTF8SKIP(s)) <= strend) {
                    if (!swash_fetch(PL_utf8_alnum, (U8*)s, do_utf8)) {
-                       if (tmp && (norun || regtry(prog, s)))
+                       if (tmp && (!reginfo || regtry(reginfo, s)))
                            goto got_it;
                        else
                            tmp = doevery;
@@ -1301,7 +1304,7 @@ S_find_byclass(pTHX_ regexp * prog, const regnode *c, char *s, const char *stren
            else {
                while (s < strend) {
                    if (!isALNUM(*s)) {
-                       if (tmp && (norun || regtry(prog, s)))
+                       if (tmp && (!reginfo || regtry(reginfo, s)))
                            goto got_it;
                        else
                            tmp = doevery;
@@ -1317,7 +1320,7 @@ S_find_byclass(pTHX_ regexp * prog, const regnode *c, char *s, const char *stren
            if (do_utf8) {
                while (s + (uskip = UTF8SKIP(s)) <= strend) {
                    if (!isALNUM_LC_utf8((U8*)s)) {
-                       if (tmp && (norun || regtry(prog, s)))
+                       if (tmp && (!reginfo || regtry(reginfo, s)))
                            goto got_it;
                        else
                            tmp = doevery;
@@ -1330,7 +1333,7 @@ S_find_byclass(pTHX_ regexp * prog, const regnode *c, char *s, const char *stren
            else {
                while (s < strend) {
                    if (!isALNUM_LC(*s)) {
-                       if (tmp && (norun || regtry(prog, s)))
+                       if (tmp && (!reginfo || regtry(reginfo, s)))
                            goto got_it;
                        else
                            tmp = doevery;
@@ -1346,7 +1349,7 @@ S_find_byclass(pTHX_ regexp * prog, const regnode *c, char *s, const char *stren
                LOAD_UTF8_CHARCLASS_SPACE();
                while (s + (uskip = UTF8SKIP(s)) <= strend) {
                    if (*s == ' ' || swash_fetch(PL_utf8_space,(U8*)s, do_utf8)) {
-                       if (tmp && (norun || regtry(prog, s)))
+                       if (tmp && (!reginfo || regtry(reginfo, s)))
                            goto got_it;
                        else
                            tmp = doevery;
@@ -1359,7 +1362,7 @@ S_find_byclass(pTHX_ regexp * prog, const regnode *c, char *s, const char *stren
            else {
                while (s < strend) {
                    if (isSPACE(*s)) {
-                       if (tmp && (norun || regtry(prog, s)))
+                       if (tmp && (!reginfo || regtry(reginfo, s)))
                            goto got_it;
                        else
                            tmp = doevery;
@@ -1375,7 +1378,7 @@ S_find_byclass(pTHX_ regexp * prog, const regnode *c, char *s, const char *stren
            if (do_utf8) {
                while (s + (uskip = UTF8SKIP(s)) <= strend) {
                    if (*s == ' ' || isSPACE_LC_utf8((U8*)s)) {
-                       if (tmp && (norun || regtry(prog, s)))
+                       if (tmp && (!reginfo || regtry(reginfo, s)))
                            goto got_it;
                        else
                            tmp = doevery;
@@ -1388,7 +1391,7 @@ S_find_byclass(pTHX_ regexp * prog, const regnode *c, char *s, const char *stren
            else {
                while (s < strend) {
                    if (isSPACE_LC(*s)) {
-                       if (tmp && (norun || regtry(prog, s)))
+                       if (tmp && (!reginfo || regtry(reginfo, s)))
                            goto got_it;
                        else
                            tmp = doevery;
@@ -1404,7 +1407,7 @@ S_find_byclass(pTHX_ regexp * prog, const regnode *c, char *s, const char *stren
                LOAD_UTF8_CHARCLASS_SPACE();
                while (s + (uskip = UTF8SKIP(s)) <= strend) {
                    if (!(*s == ' ' || swash_fetch(PL_utf8_space,(U8*)s, do_utf8))) {
-                       if (tmp && (norun || regtry(prog, s)))
+                       if (tmp && (!reginfo || regtry(reginfo, s)))
                            goto got_it;
                        else
                            tmp = doevery;
@@ -1417,7 +1420,7 @@ S_find_byclass(pTHX_ regexp * prog, const regnode *c, char *s, const char *stren
            else {
                while (s < strend) {
                    if (!isSPACE(*s)) {
-                       if (tmp && (norun || regtry(prog, s)))
+                       if (tmp && (!reginfo || regtry(reginfo, s)))
                            goto got_it;
                        else
                            tmp = doevery;
@@ -1433,7 +1436,7 @@ S_find_byclass(pTHX_ regexp * prog, const regnode *c, char *s, const char *stren
            if (do_utf8) {
                while (s + (uskip = UTF8SKIP(s)) <= strend) {
                    if (!(*s == ' ' || isSPACE_LC_utf8((U8*)s))) {
-                       if (tmp && (norun || regtry(prog, s)))
+                       if (tmp && (!reginfo || regtry(reginfo, s)))
                            goto got_it;
                        else
                            tmp = doevery;
@@ -1446,7 +1449,7 @@ S_find_byclass(pTHX_ regexp * prog, const regnode *c, char *s, const char *stren
            else {
                while (s < strend) {
                    if (!isSPACE_LC(*s)) {
-                       if (tmp && (norun || regtry(prog, s)))
+                       if (tmp && (!reginfo || regtry(reginfo, s)))
                            goto got_it;
                        else
                            tmp = doevery;
@@ -1462,7 +1465,7 @@ S_find_byclass(pTHX_ regexp * prog, const regnode *c, char *s, const char *stren
                LOAD_UTF8_CHARCLASS_DIGIT();
                while (s + (uskip = UTF8SKIP(s)) <= strend) {
                    if (swash_fetch(PL_utf8_digit,(U8*)s, do_utf8)) {
-                       if (tmp && (norun || regtry(prog, s)))
+                       if (tmp && (!reginfo || regtry(reginfo, s)))
                            goto got_it;
                        else
                            tmp = doevery;
@@ -1475,7 +1478,7 @@ S_find_byclass(pTHX_ regexp * prog, const regnode *c, char *s, const char *stren
            else {
                while (s < strend) {
                    if (isDIGIT(*s)) {
-                       if (tmp && (norun || regtry(prog, s)))
+                       if (tmp && (!reginfo || regtry(reginfo, s)))
                            goto got_it;
                        else
                            tmp = doevery;
@@ -1491,7 +1494,7 @@ S_find_byclass(pTHX_ regexp * prog, const regnode *c, char *s, const char *stren
            if (do_utf8) {
                while (s + (uskip = UTF8SKIP(s)) <= strend) {
                    if (isDIGIT_LC_utf8((U8*)s)) {
-                       if (tmp && (norun || regtry(prog, s)))
+                       if (tmp && (!reginfo || regtry(reginfo, s)))
                            goto got_it;
                        else
                            tmp = doevery;
@@ -1504,7 +1507,7 @@ S_find_byclass(pTHX_ regexp * prog, const regnode *c, char *s, const char *stren
            else {
                while (s < strend) {
                    if (isDIGIT_LC(*s)) {
-                       if (tmp && (norun || regtry(prog, s)))
+                       if (tmp && (!reginfo || regtry(reginfo, s)))
                            goto got_it;
                        else
                            tmp = doevery;
@@ -1520,7 +1523,7 @@ S_find_byclass(pTHX_ regexp * prog, const regnode *c, char *s, const char *stren
                LOAD_UTF8_CHARCLASS_DIGIT();
                while (s + (uskip = UTF8SKIP(s)) <= strend) {
                    if (!swash_fetch(PL_utf8_digit,(U8*)s, do_utf8)) {
-                       if (tmp && (norun || regtry(prog, s)))
+                       if (tmp && (!reginfo || regtry(reginfo, s)))
                            goto got_it;
                        else
                            tmp = doevery;
@@ -1533,7 +1536,7 @@ S_find_byclass(pTHX_ regexp * prog, const regnode *c, char *s, const char *stren
            else {
                while (s < strend) {
                    if (!isDIGIT(*s)) {
-                       if (tmp && (norun || regtry(prog, s)))
+                       if (tmp && (!reginfo || regtry(reginfo, s)))
                            goto got_it;
                        else
                            tmp = doevery;
@@ -1549,7 +1552,7 @@ S_find_byclass(pTHX_ regexp * prog, const regnode *c, char *s, const char *stren
            if (do_utf8) {
                while (s + (uskip = UTF8SKIP(s)) <= strend) {
                    if (!isDIGIT_LC_utf8((U8*)s)) {
-                       if (tmp && (norun || regtry(prog, s)))
+                       if (tmp && (!reginfo || regtry(reginfo, s)))
                            goto got_it;
                        else
                            tmp = doevery;
@@ -1562,7 +1565,7 @@ S_find_byclass(pTHX_ regexp * prog, const regnode *c, char *s, const char *stren
            else {
                while (s < strend) {
                    if (!isDIGIT_LC(*s)) {
-                       if (tmp && (norun || regtry(prog, s)))
+                       if (tmp && (!reginfo || regtry(reginfo, s)))
                            goto got_it;
                        else
                            tmp = doevery;
@@ -1610,6 +1613,7 @@ Perl_regexec_flags(pTHX_ register regexp *prog, char *stringarg, register char *
     SV* dsv0;
     SV* dsv1;
 #endif
+    regmatch_info reginfo;  /* create some info to pass to regtry etc */
 
     GET_RE_DEBUG_FLAGS_DECL;
 
@@ -1622,16 +1626,13 @@ Perl_regexec_flags(pTHX_ register regexp *prog, char *stringarg, register char *
     }
 
     multiline = prog->reganch & PMf_MULTILINE;
+    reginfo.prog = prog;
 
 #ifdef DEBUGGING
     dsv0 = PERL_DEBUG_PAD_ZERO(0);
     dsv1 = PERL_DEBUG_PAD_ZERO(1);
 #endif
 
-#ifdef DEBUGGING
-    PL_regnarrate = DEBUG_r_TEST;
-#endif
-
     RX_MATCH_UTF8_set(prog, do_utf8);
 
     minlen = prog->minlen;
@@ -1654,37 +1655,37 @@ Perl_regexec_flags(pTHX_ register regexp *prog, char *stringarg, register char *
        PL_reg_flags |= RF_utf8;
 
     /* Mark beginning of line for ^ and lookbehind. */
-    PL_regbol = startpos;
+    reginfo.bol = startpos; /* XXX not used ??? */
     PL_bostr  = strbeg;
-    PL_reg_sv = sv;
+    reginfo.sv = sv;
 
     /* Mark end of line for $ (and such) */
     PL_regeol = strend;
 
     /* see how far we have to get to not match where we matched before */
-    PL_regtill = startpos+minend;
+    reginfo.till = startpos+minend;
 
     /* If there is a "must appear" string, look for it. */
     s = startpos;
 
-    if (prog->reganch & ROPT_GPOS_SEEN) { /* Need to have PL_reg_ganch */
+    if (prog->reganch & ROPT_GPOS_SEEN) { /* Need to set reginfo->ganch */
        MAGIC *mg;
 
        if (flags & REXEC_IGNOREPOS)    /* Means: check only at start */
-           PL_reg_ganch = startpos;
+           reginfo.ganch = startpos;
        else if (sv && SvTYPE(sv) >= SVt_PVMG
                  && SvMAGIC(sv)
                  && (mg = mg_find(sv, PERL_MAGIC_regex_global))
                  && mg->mg_len >= 0) {
-           PL_reg_ganch = strbeg + mg->mg_len; /* Defined pos() */
+           reginfo.ganch = strbeg + mg->mg_len;        /* Defined pos() */
            if (prog->reganch & ROPT_ANCH_GPOS) {
-               if (s > PL_reg_ganch)
+               if (s > reginfo.ganch)
                    goto phooey;
-               s = PL_reg_ganch;
+               s = reginfo.ganch;
            }
        }
        else                            /* pos() not defined */
-           PL_reg_ganch = strbeg;
+           reginfo.ganch = strbeg;
     }
 
     if (!(flags & REXEC_CHECKED) && (prog->check_substr != NULL || prog->check_utf8 != NULL)) {
@@ -1726,7 +1727,7 @@ Perl_regexec_flags(pTHX_ register regexp *prog, char *stringarg, register char *
     /* Simplest case:  anchored match need be tried only once. */
     /*  [unless only anchor is BOL and multiline is set] */
     if (prog->reganch & (ROPT_ANCH & ~ROPT_ANCH_GPOS)) {
-       if (s == startpos && regtry(prog, startpos))
+       if (s == startpos && regtry(&reginfo, startpos))
            goto got_it;
        else if (multiline || (prog->reganch & ROPT_IMPLICIT)
                 || (prog->reganch & ROPT_ANCH_MBOL)) /* XXXX SBOL? */
@@ -1741,7 +1742,7 @@ Perl_regexec_flags(pTHX_ register regexp *prog, char *stringarg, register char *
                if (s == startpos)
                    goto after_try;
                while (1) {
-                   if (regtry(prog, s))
+                   if (regtry(&reginfo, s))
                        goto got_it;
                  after_try:
                    if (s >= end)
@@ -1759,7 +1760,7 @@ Perl_regexec_flags(pTHX_ register regexp *prog, char *stringarg, register char *
                    s--;
                while (s < end) {
                    if (*s++ == '\n') { /* don't need PL_utf8skip here */
-                       if (regtry(prog, s))
+                       if (regtry(&reginfo, s))
                            goto got_it;
                    }
                }               
@@ -1767,7 +1768,7 @@ Perl_regexec_flags(pTHX_ register regexp *prog, char *stringarg, register char *
        }
        goto phooey;
     } else if (prog->reganch & ROPT_ANCH_GPOS) {
-       if (regtry(prog, PL_reg_ganch))
+       if (regtry(&reginfo, reginfo.ganch))
            goto got_it;
        goto phooey;
     }
@@ -1788,7 +1789,7 @@ Perl_regexec_flags(pTHX_ register regexp *prog, char *stringarg, register char *
            while (s < strend) {
                if (*s == ch) {
                    DEBUG_EXECUTE_r( did_match = 1 );
-                   if (regtry(prog, s)) goto got_it;
+                   if (regtry(&reginfo, s)) goto got_it;
                    s += UTF8SKIP(s);
                    while (s < strend && *s == ch)
                        s += UTF8SKIP(s);
@@ -1800,7 +1801,7 @@ Perl_regexec_flags(pTHX_ register regexp *prog, char *stringarg, register char *
            while (s < strend) {
                if (*s == ch) {
                    DEBUG_EXECUTE_r( did_match = 1 );
-                   if (regtry(prog, s)) goto got_it;
+                   if (regtry(&reginfo, s)) goto got_it;
                    s++;
                    while (s < strend && *s == ch)
                        s++;
@@ -1878,14 +1879,14 @@ Perl_regexec_flags(pTHX_ register regexp *prog, char *stringarg, register char *
            }
            if (do_utf8) {
                while (s <= last1) {
-                   if (regtry(prog, s))
+                   if (regtry(&reginfo, s))
                        goto got_it;
                    s += UTF8SKIP(s);
                }
            }
            else {
                while (s <= last1) {
-                   if (regtry(prog, s))
+                   if (regtry(&reginfo, s))
                        goto got_it;
                    s++;
                }
@@ -1931,7 +1932,7 @@ Perl_regexec_flags(pTHX_ register regexp *prog, char *stringarg, register char *
                          len0, len0, s0,
                          len1, len1, s1);
        });
-        if (find_byclass(prog, c, s, strend, 0))
+        if (find_byclass(prog, c, s, strend, &reginfo))
            goto got_it;
        DEBUG_EXECUTE_r(PerlIO_printf(Perl_debug_log, "Contradicts stclass...\n"));
     }
@@ -1989,7 +1990,7 @@ Perl_regexec_flags(pTHX_ register regexp *prog, char *stringarg, register char *
        /* We don't know much -- general case. */
        if (do_utf8) {
            for (;;) {
-               if (regtry(prog, s))
+               if (regtry(&reginfo, s))
                    goto got_it;
                if (s >= strend)
                    break;
@@ -1998,7 +1999,7 @@ Perl_regexec_flags(pTHX_ register regexp *prog, char *stringarg, register char *
        }
        else {
            do {
-               if (regtry(prog, s))
+               if (regtry(&reginfo, s))
                    goto got_it;
            } while (s++ < strend);
        }
@@ -2064,12 +2065,13 @@ phooey:
  - regtry - try match at specific point
  */
 STATIC I32                     /* 0 failure, 1 success */
-S_regtry(pTHX_ regexp *prog, char *startpos)
+S_regtry(pTHX_ const regmatch_info *reginfo, char *startpos)
 {
     dVAR;
     register I32 *sp;
     register I32 *ep;
     CHECKPOINT lastcp;
+    regexp *prog = reginfo->prog;
     GET_RE_DEBUG_FLAGS_DECL;
 
 #ifdef DEBUGGING
@@ -2091,21 +2093,21 @@ S_regtry(pTHX_ regexp *prog, char *startpos)
        /* SAVEI8(cxstack[cxstack_ix].blk_gimme);
           cxstack[cxstack_ix].blk_gimme = G_SCALAR; */
 
-       if (PL_reg_sv) {
+       if (reginfo->sv) {
            /* Make $_ available to executed code. */
-           if (PL_reg_sv != DEFSV) {
+           if (reginfo->sv != DEFSV) {
                SAVE_DEFSV;
-               DEFSV = PL_reg_sv;
+               DEFSV = reginfo->sv;
            }
        
-           if (!(SvTYPE(PL_reg_sv) >= SVt_PVMG && SvMAGIC(PL_reg_sv)
-                 && (mg = mg_find(PL_reg_sv, PERL_MAGIC_regex_global)))) {
+           if (!(SvTYPE(reginfo->sv) >= SVt_PVMG && SvMAGIC(reginfo->sv)
+                 && (mg = mg_find(reginfo->sv, PERL_MAGIC_regex_global)))) {
                /* prepare for quick setting of pos */
 #ifdef PERL_OLD_COPY_ON_WRITE
                if (SvIsCOW(sv))
                    sv_force_normal_flags(sv, 0);
 #endif
-               mg = sv_magicext(PL_reg_sv, (SV*)0, PERL_MAGIC_regex_global,
+               mg = sv_magicext(reginfo->sv, (SV*)0, PERL_MAGIC_regex_global,
                                 &PL_vtbl_mglob, NULL, 0);
                mg->mg_len = -1;
            }
@@ -2189,7 +2191,7 @@ S_regtry(pTHX_ regexp *prog, char *startpos)
     }
 #endif
     REGCP_SET(lastcp);
-    if (regmatch(prog, prog->program + 1)) {
+    if (regmatch(reginfo, prog->program + 1)) {
        prog->endp[0] = PL_reginput - PL_bostr;
        return 1;
     }
@@ -2232,7 +2234,6 @@ typedef union re_unwind_t {
 #define sayNO goto no
 #define sayNO_ANYOF goto no_anyof
 #define sayYES_FINAL goto yes_final
-#define sayYES_LOUD  goto yes_loud
 #define sayNO_FINAL  goto no_final
 #define sayNO_SILENT goto do_no
 #define saySAME(x) if (x) goto yes; else goto no
@@ -2240,11 +2241,17 @@ typedef union re_unwind_t {
 #define POSCACHE_SUCCESS 0     /* caching success rather than failure */
 #define POSCACHE_SEEN 1                /* we know what we're caching */
 #define POSCACHE_START 2       /* the real cache: this bit maps to pos 0 */
+
 #define CACHEsayYES STMT_START { \
     if (st->u.whilem.cache_offset | st->u.whilem.cache_bit) { \
-       if (!(PL_reg_poscache[0] & (1<<POSCACHE_SEEN))) \
-           PL_reg_poscache[0] |= (1<<POSCACHE_SUCCESS) || (1<<POSCACHE_SEEN); \
-        else if (!(PL_reg_poscache[0] & (1<<POSCACHE_SUCCESS))) { \
+       if (!(PL_reg_poscache[0] & (1<<POSCACHE_SEEN))) { \
+           PL_reg_poscache[0] |= (1<<POSCACHE_SUCCESS) | (1<<POSCACHE_SEEN); \
+           PL_reg_poscache[st->u.whilem.cache_offset] |= (1<<st->u.whilem.cache_bit); \
+       } \
+        else if (PL_reg_poscache[0] & (1<<POSCACHE_SUCCESS)) { \
+           PL_reg_poscache[st->u.whilem.cache_offset] |= (1<<st->u.whilem.cache_bit); \
+       } \
+       else { \
            /* cache records failure, but this is success */ \
            DEBUG_r( \
                PerlIO_printf(Perl_debug_log, \
@@ -2256,11 +2263,17 @@ typedef union re_unwind_t {
     } \
     sayYES; \
 } STMT_END
+
 #define CACHEsayNO STMT_START { \
     if (st->u.whilem.cache_offset | st->u.whilem.cache_bit) { \
-       if (!(PL_reg_poscache[0] & (1<<POSCACHE_SEEN))) \
+       if (!(PL_reg_poscache[0] & (1<<POSCACHE_SEEN))) \
            PL_reg_poscache[0] |= (1<<POSCACHE_SEEN); \
-        else if ((PL_reg_poscache[0] & (1<<POSCACHE_SUCCESS))) { \
+           PL_reg_poscache[st->u.whilem.cache_offset] |= (1<<st->u.whilem.cache_bit); \
+       } \
+        else if (!(PL_reg_poscache[0] & (1<<POSCACHE_SUCCESS))) { \
+           PL_reg_poscache[st->u.whilem.cache_offset] |= (1<<st->u.whilem.cache_bit); \
+       } \
+       else { \
            /* cache records success, but this is failure */ \
            DEBUG_r( \
                PerlIO_printf(Perl_debug_log, \
@@ -2285,6 +2298,9 @@ typedef union re_unwind_t {
 /* Make sure there is a test for this +1 options in re_tests */
 #define TRIE_INITAL_ACCEPT_BUFFLEN 4;
 
+#define SLAB_FIRST(s) (&(s)->states[0])
+#define SLAB_LAST(s)  (&(s)->states[PERL_REGMATCH_SLAB_SLOTS-1])
+
 /* grab a new slab and return the first slot in it */
 
 STATIC regmatch_state *
@@ -2298,7 +2314,7 @@ S_push_slab(pTHX)
        PL_regmatch_slab->next = s;
     }
     PL_regmatch_slab = s;
-    return &s->states[0];
+    return SLAB_FIRST(s);
 }
 
 /* simulate a recursive call to regmatch */
@@ -2322,7 +2338,7 @@ S_push_slab(pTHX)
     st->locinput = locinput;   \
     st->resume_state = resume; \
     newst = st+1;   \
-    if (newst >  &(PL_regmatch_slab->states[PERL_REGMATCH_SLAB_SLOTS-1])) \
+    if (newst >  SLAB_LAST(PL_regmatch_slab)) \
        newst = S_push_slab(aTHX);  \
     PL_regmatch_state = newst; \
     newst->cc = 0;  \
@@ -2337,9 +2353,9 @@ S_push_slab(pTHX)
     DEBUG_EXECUTE_r(PerlIO_printf(Perl_debug_log, "POP STATE(%d)\n", depth)); \
     depth--; \
     st--; \
-    if (st < &PL_regmatch_slab->states[0]) { \
+    if (st < SLAB_FIRST(PL_regmatch_slab)) { \
        PL_regmatch_slab = PL_regmatch_slab->prev; \
-       st = &PL_regmatch_slab->states[PERL_REGMATCH_SLAB_SLOTS-1]; \
+       st = SLAB_LAST(PL_regmatch_slab); \
     } \
     PL_regmatch_state = st; \
     scan       = st->scan; \
@@ -2455,12 +2471,14 @@ S_push_slab(pTHX)
  
 
 STATIC I32                     /* 0 failure, 1 success */
-S_regmatch(pTHX_ regexp *rex, regnode *prog)
+S_regmatch(pTHX_ const regmatch_info *reginfo, regnode *prog)
 {
     dVAR;
     register const bool do_utf8 = PL_reg_match_utf8;
     const U32 uniflags = UTF8_ALLOW_DEFAULT;
 
+    regexp *rex = reginfo->prog;
+
     regmatch_slab  *orig_slab;
     regmatch_state *orig_state;
 
@@ -2479,7 +2497,8 @@ S_regmatch(pTHX_ regexp *rex, regnode *prog)
     regnode *inner;        /* Next node in internal branch. */
     int depth = 0;         /* depth of recursion */
     regmatch_state *newst;  /* when pushing a state, this is the new one */
-    regmatch_state *cur_eval = NULL;  /* most recent (??{}) state */
+    regmatch_state *yes_state = NULL; /* state to pop to on success of
+                                                           subpattern */
     
 #ifdef DEBUGGING
     SV *re_debug_flags = NULL;
@@ -2492,7 +2511,7 @@ S_regmatch(pTHX_ regexp *rex, regnode *prog)
        Newx(PL_regmatch_slab, 1, regmatch_slab);
        PL_regmatch_slab->prev = NULL;
        PL_regmatch_slab->next = NULL;
-       PL_regmatch_state = &PL_regmatch_slab->states[0] - 1;
+       PL_regmatch_state = SLAB_FIRST(PL_regmatch_slab);
     }
 
     /* remember current high-water mark for exit */
@@ -2502,7 +2521,7 @@ S_regmatch(pTHX_ regexp *rex, regnode *prog)
 
     /* grab next free state slot */
     st = ++PL_regmatch_state;
-    if (st >  &(PL_regmatch_slab->states[PERL_REGMATCH_SLAB_SLOTS-1]))
+    if (st >  SLAB_LAST(PL_regmatch_slab))
        st = PL_regmatch_state = S_push_slab(aTHX);
 
     st->minmod = 0;
@@ -2589,7 +2608,7 @@ S_regmatch(pTHX_ regexp *rex, regnode *prog)
        case BOL:
            if (locinput == PL_bostr)
            {
-               /* regtill = regbol; */
+               /* reginfo->till = reginfo->bol; */
                break;
            }
            sayNO;
@@ -2605,7 +2624,7 @@ S_regmatch(pTHX_ regexp *rex, regnode *prog)
                break;
            sayNO;
        case GPOS:
-           if (locinput == PL_reg_ganch)
+           if (locinput == reginfo->ganch)
                break;
            sayNO;
        case EOL:
@@ -3395,10 +3414,9 @@ S_regmatch(pTHX_ regexp *rex, regnode *prog)
                st->u.eval.prev_rex = rex;
                rex = re;
 
-               st->u.eval.prev_eval = cur_eval;
-               st->u.eval.prev_slab = PL_regmatch_slab;
-               st->u.eval.depth = depth;
-               cur_eval = st;
+               /* resume to current state on success */
+               st->u.yes.prev_yes_state = yes_state;
+               yes_state = st;
                PUSH_STATE(newst, resume_EVAL);
                st = newst;
 
@@ -3524,7 +3542,19 @@ S_regmatch(pTHX_ regexp *rex, regnode *prog)
                /* No need to save/restore up to this paren */
                I32 parenfloor = scan->flags;
 
-               if (next && (OP(PREVOPER(next)) == NOTHING)) /* LONGJMP */
+               /* Dave says:
+                  
+                  CURLYX and WHILEM are always paired: they're the moral
+                  equivalent of pp_enteriter anbd pp_iter.
+
+                  The only time next could be null is if the node tree is
+                  corrupt. This was mentioned on p5p a few days ago.
+
+                  See http://www.xray.mpe.mpg.de/mailing-lists/perl5-porters/2006-04/msg00556.html
+                  So we'll assert that this is true:
+               */
+               assert(next);
+               if (OP(PREVOPER(next)) == NOTHING) /* LONGJMP */
                    next += ARG(next);
                /* XXXX Probably it is better to teach regpush to support
                   parenfloor > PL_regsize... */
@@ -3563,6 +3593,16 @@ S_regmatch(pTHX_ regexp *rex, regnode *prog)
                 * that we can try again after backing off.
                 */
 
+               /* Dave says:
+
+                  st->cc gets initialised by CURLYX ready for use by WHILEM.
+                  So again, unless somethings been corrupted, st->cc cannot
+                  be null at that point in WHILEM.
+                  
+                  See http://www.xray.mpe.mpg.de/mailing-lists/perl5-porters/2006-04/msg00556.html
+                  So we'll assert that this is true:
+               */
+               assert(st->cc);
                st->u.whilem.lastloc = st->cc->u.curlyx.lastloc; /* Detection of 0-len. */
                st->u.whilem.cache_offset = 0;
                st->u.whilem.cache_bit = 0;
@@ -3661,7 +3701,6 @@ S_regmatch(pTHX_ regexp *rex, regnode *prog)
                            /* cache records failure */
                            sayNO_SILENT;
                    }
-                   PL_reg_poscache[st->u.whilem.cache_offset] |= (1<<st->u.whilem.cache_bit);
                }
                }
 
@@ -3835,7 +3874,11 @@ S_regmatch(pTHX_ regexp *rex, regnode *prog)
            st->u.curlym.maxwanted = st->minmod ? st->ln : n;
            if (st->u.curlym.maxwanted) {
                while (PL_reginput < PL_regeol && st->u.curlym.matches < st->u.curlym.maxwanted) {
+                   /* resume to current state on success */
+                   st->u.yes.prev_yes_state = yes_state;
+                   yes_state = st;
                    REGMATCH(scan, CURLYM1);
+                   yes_state = st->u.yes.prev_yes_state;
                    /*** all unsaved local vars undefined at this point */
                    if (!result)
                        break;
@@ -3905,15 +3948,24 @@ S_regmatch(pTHX_ regexp *rex, regnode *prog)
                            else
                                PL_regendp[st->u.curlym.paren] = -1;
                        }
+                       /* resume to current state on success */
+                       st->u.yes.prev_yes_state = yes_state;
+                       yes_state = st;
                        REGMATCH(next, CURLYM2);
+                       yes_state = st->u.yes.prev_yes_state;
                        /*** all unsaved local vars undefined at this point */
                        if (result)
-                           sayYES;
+                           /* XXX tmp sayYES; */
+                           sayYES_FINAL;
                        REGCP_UNWIND(st->u.curlym.lastcp);
                    }
                    /* Couldn't or didn't -- move forward. */
                    PL_reginput = locinput;
+                   /* resume to current state on success */
+                   st->u.yes.prev_yes_state = yes_state;
+                   yes_state = st;
                    REGMATCH(scan, CURLYM3);
+                   yes_state = st->u.yes.prev_yes_state;
                    /*** all unsaved local vars undefined at this point */
                    if (result) {
                        st->ln++;
@@ -3978,10 +4030,15 @@ S_regmatch(pTHX_ regexp *rex, regnode *prog)
                            else
                                PL_regendp[st->u.curlym.paren] = -1;
                        }
+                       /* resume to current state on success */
+                       st->u.yes.prev_yes_state = yes_state;
+                       yes_state = st;
                        REGMATCH(next, CURLYM4);
+                       yes_state = st->u.yes.prev_yes_state;
                        /*** all unsaved local vars undefined at this point */
                        if (result)
-                           sayYES;
+                           /* XXX tmp sayYES; */
+                           sayYES_FINAL;
                        REGCP_UNWIND(st->u.curlym.lastcp);
                    }
                    /* Couldn't or didn't -- back up. */
@@ -4247,113 +4304,68 @@ S_regmatch(pTHX_ regexp *rex, regnode *prog)
            sayNO;
            break;
        case END:
-           if (cur_eval) {
-               /* we have successfully completed the execution of a
-                * postponed re. Pop all states back to the last EVAL
-                * then continue with the node following the (??{...})
-                */
-
-               /* this simulates a POP_STATE, except that it pops several
-                * levels, and doesn't restore locinput */
-
-               st = cur_eval;
-               PL_regmatch_slab = st->u.eval.prev_slab;
-               cur_eval = st->u.eval.prev_eval;
-               depth = st->u.eval.depth;
-
-               PL_regmatch_state = st;
-               scan    = st->scan;
-               next    = st->next;
-               n               = st->n;
-
-               if (st->u.eval.toggleutf)
-                   PL_reg_flags ^= RF_utf8;
-               ReREFCNT_dec(rex);
-               rex = st->u.eval.prev_rex;
-               /* XXXX This is too dramatic a measure... */
-               PL_reg_maxiter = 0;
-
-               /* Restore parens of the caller without popping the
-                * savestack */
-               {
-                   I32 tmp = PL_savestack_ix;
-                   PL_savestack_ix = st->u.eval.lastcp;
-                   regcppop(rex);
-                   PL_savestack_ix = tmp;
-               }
-
-
-               PL_reginput = locinput;
-               /* resume at node following the (??{...}) */
-               break;
-
-           }
-
-           if (locinput < PL_regtill) {
+           if (locinput < reginfo->till) {
                DEBUG_EXECUTE_r(PerlIO_printf(Perl_debug_log,
                                      "%sMatch possible, but length=%ld is smaller than requested=%ld, failing!%s\n",
                                      PL_colors[4],
                                      (long)(locinput - PL_reg_starttry),
-                                     (long)(PL_regtill - PL_reg_starttry),
+                                     (long)(reginfo->till - PL_reg_starttry),
                                      PL_colors[5]));
                sayNO_FINAL;            /* Cannot match: too short. */
            }
            PL_reginput = locinput;     /* put where regtry can find it */
            sayYES_FINAL;               /* Success! */
-       case SUCCEED:
+
+       case SUCCEED: /* successful SUSPEND/UNLESSM/IFMATCH/CURLYM */
+           DEBUG_EXECUTE_r(
+           PerlIO_printf(Perl_debug_log,
+               "%*s  %ssubpattern success...%s\n",
+               REPORT_CODE_OFF+PL_regindent*2, "", PL_colors[4], PL_colors[5]));
            PL_reginput = locinput;     /* put where regtry can find it */
-           sayYES_LOUD;                /* Success! */
-       case SUSPEND:
-           n = 1;
+           sayYES_FINAL;               /* Success! */
+
+       case SUSPEND:   /* (?>FOO) */
+           st->u.ifmatch.wanted = 1;
            PL_reginput = locinput;
            goto do_ifmatch;    
-       case UNLESSM:
-           n = 0;
-           if (scan->flags) {
-               char * const s = HOPBACKc(locinput, scan->flags);
-               if (!s)
-                   goto say_yes;
-               PL_reginput = s;
-           }
-           else
-               PL_reginput = locinput;
-           goto do_ifmatch;
-       case IFMATCH:
-           n = 1;
+
+       case UNLESSM:   /* -ve lookaround: (?!FOO), or with flags, (?<!foo) */
+           st->u.ifmatch.wanted = 0;
+           goto ifmatch_trivial_fail_test;
+
+       case IFMATCH:   /* +ve lookaround: (?=FOO), or with flags, (?<=foo) */
+           st->u.ifmatch.wanted = 1;
+         ifmatch_trivial_fail_test:
            if (scan->flags) {
                char * const s = HOPBACKc(locinput, scan->flags);
-               if (!s)
-                   goto say_no;
+               if (!s) {
+                   /* trivial fail */
+                   if (st->logical) {
+                       st->logical = 0;
+                       st->sw = 1 - st->u.ifmatch.wanted;
+                   }
+                   else if (st->u.ifmatch.wanted)
+                       sayNO;
+                   next = scan + ARG(scan);
+                   if (next == scan)
+                       next = NULL;
+                   break;
+               }
                PL_reginput = s;
            }
            else
                PL_reginput = locinput;
 
          do_ifmatch:
-           REGMATCH(NEXTOPER(NEXTOPER(scan)), IFMATCH);
-           /*** all unsaved local vars undefined at this point */
-           if (result != n) {
-             say_no:
-               if (st->logical) {
-                   st->logical = 0;
-                   st->sw = 0;
-                   goto do_longjump;
-               }
-               else
-                   sayNO;
-           }
-         say_yes:
-           if (st->logical) {
-               st->logical = 0;
-               st->sw = 1;
-           }
-           if (OP(scan) == SUSPEND) {
-               locinput = PL_reginput;
-               nextchr = UCHARAT(locinput);
-           }
-           /* FALL THROUGH. */
+           /* resume to current state on success */
+           st->u.yes.prev_yes_state = yes_state;
+           yes_state = st;
+           PUSH_STATE(newst, resume_IFMATCH);
+           st = newst;
+           next = NEXTOPER(NEXTOPER(scan));
+           break;
+
        case LONGJMP:
-         do_longjump:
            next = scan + ARG(scan);
            if (next == scan)
                next = NULL;
@@ -4383,7 +4395,7 @@ S_regmatch(pTHX_ regexp *rex, regnode *prog)
 
            /* grab the next free state slot */
            st++;
-           if (st >  &(PL_regmatch_slab->states[PERL_REGMATCH_SLAB_SLOTS-1]))
+           if (st >  SLAB_LAST(PL_regmatch_slab))
                st = S_push_slab(aTHX);
            PL_regmatch_state = st;
 
@@ -4414,14 +4426,90 @@ S_regmatch(pTHX_ regexp *rex, regnode *prog)
     /*NOTREACHED*/
     sayNO;
 
-yes_loud:
-    DEBUG_EXECUTE_r(
-       PerlIO_printf(Perl_debug_log,
-                     "%*s  %scould match...%s\n",
-                     REPORT_CODE_OFF+PL_regindent*2, "", PL_colors[4], PL_colors[5])
-       );
-    goto yes;
 yes_final:
+
+    if (yes_state) {
+       /* we have successfully completed a subexpression, but we must now
+        * pop to the state marked by yes_state and continue from there */
+
+       /*XXX tmp for CURLYM*/
+       regmatch_slab *oslab = PL_regmatch_slab;
+       regmatch_state *ost = st, *oys=yes_state;
+       int odepth = depth;
+
+       assert(st != yes_state);
+       while (yes_state < SLAB_FIRST(PL_regmatch_slab)
+           || yes_state > SLAB_LAST(PL_regmatch_slab))
+       {
+           /* not in this slab, pop slab */
+           depth -= (st - SLAB_FIRST(PL_regmatch_slab) + 1);
+           PL_regmatch_slab = PL_regmatch_slab->prev;
+           st = SLAB_LAST(PL_regmatch_slab);
+       }
+       depth -= (st - yes_state);
+       DEBUG_EXECUTE_r(PerlIO_printf(Perl_debug_log, "POP STATE TO (%d)\n", depth));
+       st = yes_state;
+       yes_state = st->u.yes.prev_yes_state;
+       PL_regmatch_state = st;
+
+       switch (st->resume_state) {
+       case resume_EVAL:
+           if (st->u.eval.toggleutf)
+               PL_reg_flags ^= RF_utf8;
+           ReREFCNT_dec(rex);
+           rex = st->u.eval.prev_rex;
+           /* XXXX This is too dramatic a measure... */
+           PL_reg_maxiter = 0;
+           /* Restore parens of the caller without popping the
+            * savestack */
+           {
+               I32 tmp = PL_savestack_ix;
+               PL_savestack_ix = st->u.eval.lastcp;
+               regcppop(rex);
+               PL_savestack_ix = tmp;
+           }
+           PL_reginput = locinput;
+            /* continue at the node following the (??{...}) */
+           next        = st->next;
+           goto reenter;
+
+       case resume_IFMATCH:
+           if (st->logical) {
+               st->logical = 0;
+               st->sw = st->u.ifmatch.wanted;
+           }
+           else if (!st->u.ifmatch.wanted)
+               sayNO;
+
+           if (OP(st->scan) == SUSPEND)
+               locinput = PL_reginput;
+           else {
+               locinput = PL_reginput = st->locinput;
+               nextchr = UCHARAT(locinput);
+           }
+           next = st->scan + ARG(st->scan);
+           if (next == st->scan)
+               next = NULL;
+           goto reenter;
+
+       /* XXX tmp  don't handle yes_state yet */
+       case resume_CURLYM1:
+       case resume_CURLYM2:
+       case resume_CURLYM3:
+       case resume_CURLYM4:
+           PL_regmatch_slab =oslab;
+           st = ost;
+           PL_regmatch_state = st;
+           depth = odepth;
+           yes_state = oys;
+           DEBUG_EXECUTE_r(PerlIO_printf(Perl_debug_log, "XXX revering a CURLYM\n"));
+           goto yes;
+
+       default:
+           Perl_croak(aTHX_ "unexpected yes reume state");
+       }
+    }
+
     DEBUG_EXECUTE_r(PerlIO_printf(Perl_debug_log, "%sMatch successful!%s\n",
                          PL_colors[4], PL_colors[5]));
 yes:
@@ -4431,7 +4519,8 @@ yes:
 
     result = 1;
     /* XXX this is duplicate(ish) code to that in the do_no section.
-     * eventually a yes should just pop the whole stack */
+     * eventually a yes should just pop the stack back to the current
+     * yes_state */
     if (depth) {
        /* restore previous state and re-enter */
        POP_STATE;
@@ -4441,8 +4530,6 @@ yes:
            goto resume_point_TRIE1;
        case resume_TRIE2:
            goto resume_point_TRIE2;
-       case resume_EVAL:
-           break;
        case resume_CURLYX:
            goto resume_point_CURLYX;
        case resume_WHILEM1:
@@ -4465,8 +4552,6 @@ yes:
            goto resume_point_CURLYM3;
        case resume_CURLYM4:
            goto resume_point_CURLYM4;
-       case resume_IFMATCH:
-           goto resume_point_IFMATCH;
        case resume_PLUS1:
            goto resume_point_PLUS1;
        case resume_PLUS2:
@@ -4475,6 +4560,9 @@ yes:
            goto resume_point_PLUS3;
        case resume_PLUS4:
            goto resume_point_PLUS4;
+
+       case resume_IFMATCH:
+       case resume_EVAL:
        default:
            Perl_croak(aTHX_ "regexp resume memory corruption");
        }
@@ -4560,7 +4648,7 @@ do_no:
                PL_reg_flags ^= RF_utf8;
            ReREFCNT_dec(rex);
            rex = st->u.eval.prev_rex;
-           cur_eval = st->u.eval.prev_eval;
+           yes_state = st->u.yes.prev_yes_state;
 
            /* XXXX This is too dramatic a measure... */
            PL_reg_maxiter = 0;
@@ -4593,7 +4681,22 @@ do_no:
        case resume_CURLYM4:
            goto resume_point_CURLYM4;
        case resume_IFMATCH:
-           goto resume_point_IFMATCH;
+           yes_state = st->u.yes.prev_yes_state;
+           if (st->logical) {
+               st->logical = 0;
+               st->sw = !st->u.ifmatch.wanted;
+           }
+           else if (st->u.ifmatch.wanted)
+               sayNO;
+
+           assert(OP(scan) != SUSPEND); /* XXX DAPM tmp */
+           locinput = PL_reginput = st->locinput;
+           nextchr = UCHARAT(locinput);
+           next = scan + ARG(scan);
+           if (next == scan)
+               next = NULL;
+           goto reenter;
+
        case resume_PLUS1:
            goto resume_point_PLUS1;
        case resume_PLUS2: