Comment on comment.
[p5sagit/p5-mst-13.2.git] / regexec.c
index f1b3590..52aed0a 100644 (file)
--- a/regexec.c
+++ b/regexec.c
@@ -66,7 +66,7 @@
  *
  ****    Alterations to Henry's code are...
  ****
- ****    Copyright (c) 1991-1999, Larry Wall
+ ****    Copyright (c) 1991-2000, Larry Wall
  ****
  ****    You may distribute under the terms of either the GNU General Public
  ****    License or the Artistic License, as specified in the README file.
@@ -145,14 +145,14 @@ S_regcppush(pTHX_ I32 parenfloor)
 }
 
 /* These are needed since we do not localize EVAL nodes: */
-#  define REGCP_SET  DEBUG_r(PerlIO_printf(Perl_debug_log,             \
+#  define REGCP_SET(cp)  DEBUG_r(PerlIO_printf(Perl_debug_log,         \
                             "  Setting an EVAL scope, savestack=%"IVdf"\n",    \
-                            (IV)PL_savestack_ix)); lastcp = PL_savestack_ix
+                            (IV)PL_savestack_ix)); cp = PL_savestack_ix
 
-#  define REGCP_UNWIND  DEBUG_r(lastcp != PL_savestack_ix ?            \
+#  define REGCP_UNWIND(cp)  DEBUG_r(cp != PL_savestack_ix ?            \
                                PerlIO_printf(Perl_debug_log,           \
                                "  Clearing an EVAL scope, savestack=%"IVdf"..%"IVdf"\n", \
-                               (IV)lastcp, (IV)PL_savestack_ix) : 0); regcpblow(lastcp)
+                               (IV)(cp), (IV)PL_savestack_ix) : 0); regcpblow(cp)
 
 STATIC char *
 S_regcppop(pTHX)
@@ -219,7 +219,23 @@ typedef struct re_cc_state
     regexp *re;
 } re_cc_state;
 
-#define regcpblow(cp) LEAVE_SCOPE(cp)
+#define regcpblow(cp) LEAVE_SCOPE(cp)  /* Ignores regcppush()ed data. */
+
+#define TRYPAREN(paren, n, input) {                            \
+    if (paren) {                                               \
+       if (n) {                                                \
+           PL_regstartp[paren] = HOPc(input, -1) - PL_bostr;   \
+           PL_regendp[paren] = input - PL_bostr;               \
+       }                                                       \
+       else                                                    \
+           PL_regendp[paren] = -1;                             \
+    }                                                          \
+    if (regmatch(next))                                                \
+       sayYES;                                                 \
+    if (paren && n)                                            \
+       PL_regendp[paren] = -1;                                 \
+}
+
 
 /*
  * pregexec and friends
@@ -309,6 +325,7 @@ Perl_re_intuit_start(pTHX_ regexp *prog, SV *sv, char *strpos,
     register I32 end_shift;
     register char *s;
     register SV *check;
+    char *strbeg;
     char *t;
     I32 ml_anch;
     char *tmp;
@@ -335,24 +352,29 @@ Perl_re_intuit_start(pTHX_ regexp *prog, SV *sv, char *strpos,
        DEBUG_r(PerlIO_printf(Perl_debug_log, "String too short...\n"));
        goto fail;
     }
+    strbeg = (sv && SvPOK(sv)) ? strend - SvCUR(sv) : strpos;
+    check = prog->check_substr;
     if (prog->reganch & ROPT_ANCH) {   /* Match at beg-of-str or after \n */
        ml_anch = !( (prog->reganch & ROPT_ANCH_SINGLE)
                     || ( (prog->reganch & ROPT_ANCH_BOL)
                          && !PL_multiline ) ); /* Check after \n? */
 
-       if ((prog->check_offset_min == prog->check_offset_max) && !ml_anch) {
+       if (!ml_anch) {
+         if ( !(prog->reganch & ROPT_ANCH_GPOS) /* Checked by the caller */
+              /* SvCUR is not set on references: SvRV and SvPVX overlap */
+              && sv && !SvROK(sv)
+              && (strpos != strbeg)) {
+             DEBUG_r(PerlIO_printf(Perl_debug_log, "Not at start...\n"));
+             goto fail;
+         }
+         if (prog->check_offset_min == prog->check_offset_max) {
            /* Substring at constant offset from beg-of-str... */
            I32 slen;
 
-           if ( !(prog->reganch & ROPT_ANCH_GPOS) /* Checked by the caller */
-                && (sv && (strpos + SvCUR(sv) != strend)) ) {
-               DEBUG_r(PerlIO_printf(Perl_debug_log, "Not at start...\n"));
-               goto fail;
-           }
            PL_regeol = strend;                 /* Used in HOP() */
            s = HOPc(strpos, prog->check_offset_min);
-           if (SvTAIL(prog->check_substr)) {
-               slen = SvCUR(prog->check_substr);       /* >= 1 */
+           if (SvTAIL(check)) {
+               slen = SvCUR(check);    /* >= 1 */
 
                if ( strend - s > slen || strend - s < slen - 1 
                     || (strend - s == slen && strend[-1] != '\n')) {
@@ -361,29 +383,29 @@ Perl_re_intuit_start(pTHX_ regexp *prog, SV *sv, char *strpos,
                }
                /* Now should match s[0..slen-2] */
                slen--;
-               if (slen && (*SvPVX(prog->check_substr) != *s
+               if (slen && (*SvPVX(check) != *s
                             || (slen > 1
-                                && memNE(SvPVX(prog->check_substr), s, slen)))) {
+                                && memNE(SvPVX(check), s, slen)))) {
                  report_neq:
                    DEBUG_r(PerlIO_printf(Perl_debug_log, "String not equal...\n"));
                    goto fail_finish;
                }
            }
-           else if (*SvPVX(prog->check_substr) != *s
-                    || ((slen = SvCUR(prog->check_substr)) > 1
-                        && memNE(SvPVX(prog->check_substr), s, slen)))
+           else if (*SvPVX(check) != *s
+                    || ((slen = SvCUR(check)) > 1
+                        && memNE(SvPVX(check), s, slen)))
                goto report_neq;
            goto success_at_start;
+         }
        }
        /* Match is anchored, but substr is not anchored wrt beg-of-str. */
        s = strpos;
        start_shift = prog->check_offset_min; /* okay to underestimate on CC */
-       /* Should be nonnegative! */
        end_shift = prog->minlen - start_shift -
-           CHR_SVLEN(prog->check_substr) + (SvTAIL(prog->check_substr) != 0);
+           CHR_SVLEN(check) + (SvTAIL(check) != 0);
        if (!ml_anch) {
-           I32 end = prog->check_offset_max + CHR_SVLEN(prog->check_substr)
-                                        - (SvTAIL(prog->check_substr) != 0);
+           I32 end = prog->check_offset_max + CHR_SVLEN(check)
+                                        - (SvTAIL(check) != 0);
            I32 eshift = strend - s - end;
 
            if (end_shift < eshift)
@@ -396,7 +418,7 @@ Perl_re_intuit_start(pTHX_ regexp *prog, SV *sv, char *strpos,
        start_shift = prog->check_offset_min; /* okay to underestimate on CC */
        /* Should be nonnegative! */
        end_shift = prog->minlen - start_shift -
-           CHR_SVLEN(prog->check_substr) + (SvTAIL(prog->check_substr) != 0);
+           CHR_SVLEN(check) + (SvTAIL(check) != 0);
     }
 
 #ifdef DEBUGGING       /* 7/99: reports of failure (with the older version) */
@@ -404,12 +426,10 @@ Perl_re_intuit_start(pTHX_ regexp *prog, SV *sv, char *strpos,
        Perl_croak(aTHX_ "panic: end_shift");
 #endif
 
-    check = prog->check_substr;
   restart:
     /* Find a possible match in the region s..strend by looking for
        the "check" substring in the region corrected by start/end_shift. */
     if (flags & REXEC_SCREAM) {
-       char *strbeg = SvPVX(sv);       /* XXXX Assume PV_force() on SCREAM! */
        I32 p = -1;                     /* Internal iterator of scream. */
        I32 *pp = data ? data->scream_pos : &p;
 
@@ -598,9 +618,10 @@ Perl_re_intuit_start(pTHX_ regexp *prog, SV *sv, char *strpos,
          find_anchor:
            while (t < strend - prog->minlen) {
                if (*t == '\n') {
-                   if (t < s - prog->check_offset_min) {
+                   if (t < check_at - prog->check_offset_min) {
                        if (prog->anchored_substr) {
-                           /* We definitely contradict the found anchored
+                           /* Since we moved from the found position,
+                              we definitely contradict the found anchored
                               substr.  Due to the above check we do not
                               contradict "check" substr.
                               Thus we can arrive here only if check substr
@@ -611,14 +632,19 @@ Perl_re_intuit_start(pTHX_ regexp *prog, SV *sv, char *strpos,
                                PL_colors[0],PL_colors[1], (long)(strpos - i_strpos), (long)(strpos - i_strpos + prog->anchored_offset)));
                            goto do_other_anchored;
                        }
+                       /* We don't contradict the found floating substring. */
+                       /* XXXX Why not check for STCLASS? */
                        s = t + 1;
                        DEBUG_r(PerlIO_printf(Perl_debug_log, "Found /%s^%s/m at offset %ld...\n",
                            PL_colors[0],PL_colors[1], (long)(s - i_strpos)));
                        goto set_useful;
                    }
-                   DEBUG_r(PerlIO_printf(Perl_debug_log, "Found /%s^%s/m, restarting at offset %ld...\n",
+                   /* Position contradicts check-string */
+                   /* XXXX probably better to look for check-string
+                      than for "\n", so one should lower the limit for t? */
+                   DEBUG_r(PerlIO_printf(Perl_debug_log, "Found /%s^%s/m, restarting lookup for check-string at offset %ld...\n",
                        PL_colors[0],PL_colors[1], (long)(t + 1 - i_strpos)));
-                   strpos = s = t + 1;
+                   other_last = strpos = s = t + 1;
                    goto restart;
                }
                t++;
@@ -627,35 +653,47 @@ Perl_re_intuit_start(pTHX_ regexp *prog, SV *sv, char *strpos,
                        PL_colors[0],PL_colors[1]));
            goto fail_finish;
        }
+       else {
+           DEBUG_r(PerlIO_printf(Perl_debug_log, "Starting position does not contradict /%s^%s/m...\n",
+                       PL_colors[0],PL_colors[1]));
+       }
        s = t;
       set_useful:
        ++BmUSEFUL(prog->check_substr); /* hooray/5 */
     }
     else {
        PL_bostr = tmp;
-       /* The found string does not prohibit matching at beg-of-str
+       /* The found string does not prohibit matching at strpos,
           - no optimization of calling REx engine can be performed,
-          unless it was an MBOL and we are not after MBOL. */
+          unless it was an MBOL and we are not after MBOL,
+          or a future STCLASS check will fail this. */
       try_at_start:
        /* Even in this situation we may use MBOL flag if strpos is offset
           wrt the start of the string. */
-       if (ml_anch && sv
-           && (strpos + SvCUR(sv) != strend) && strpos[-1] != '\n') {
+       if (ml_anch && sv && !SvROK(sv) /* See prev comment on SvROK */
+           && (strpos != strbeg) && strpos[-1] != '\n'
+           /* May be due to an implicit anchor of m{.*foo}  */
+           && !(prog->reganch & ROPT_IMPLICIT))
+       {
            t = strpos;
            goto find_anchor;
        }
        DEBUG_r( if (ml_anch)
-           PerlIO_printf(Perl_debug_log, "Does not contradict /%s^%s/m...\n",
-                       PL_colors[0],PL_colors[1]);
+           PerlIO_printf(Perl_debug_log, "Position at offset %ld does not contradict /%s^%s/m...\n",
+                       (long)(strpos - i_strpos), PL_colors[0],PL_colors[1]);
        );
       success_at_start:
        if (!(prog->reganch & ROPT_NAUGHTY)     /* XXXX If strpos moved? */
+           && prog->check_substr               /* Could be deleted already */
            && --BmUSEFUL(prog->check_substr) < 0
-           && prog->check_substr == prog->float_substr) { /* boo */
+           && prog->check_substr == prog->float_substr)
+       {
            /* If flags & SOMETHING - do not do it many times on the same match */
+           DEBUG_r(PerlIO_printf(Perl_debug_log, "... Disabling check substring...\n"));
            SvREFCNT_dec(prog->check_substr);
            prog->check_substr = Nullsv;        /* disable */
            prog->float_substr = Nullsv;        /* clear */
+           check = Nullsv;                     /* abort */
            s = strpos;
            /* XXXX This is a remnant of the old implementation.  It
                    looks wasteful, since now INTUIT can use many
@@ -677,13 +715,20 @@ Perl_re_intuit_start(pTHX_ regexp *prog, SV *sv, char *strpos,
           regstclass does not come from lookahead...  */
        /* If regstclass takes bytelength more than 1: If charlength==1, OK.
           This leaves EXACTF only, which is dealt with in find_byclass().  */
+       int cl_l = (PL_regkind[(U8)OP(prog->regstclass)] == EXACT
+                   ? STR_LEN(prog->regstclass)
+                   : 1);
        char *endpos = (prog->anchored_substr || ml_anch)
-               ? s + (prog->minlen? 1 : 0)
-               : (prog->float_substr ? check_at - start_shift + 1
+               ? s + (prog->minlen? cl_l : 0)
+               : (prog->float_substr ? check_at - start_shift + cl_l
                                      : strend) ;
-       char *startpos = sv ? strend - SvCUR(sv) : s;
+       char *startpos = strbeg;
 
        t = s;
+       if (prog->reganch & ROPT_UTF8) {        
+           PL_regdata = prog->data;    /* Used by REGINCLASS UTF logic */
+           PL_bostr = startpos;
+       }
         s = find_byclass(prog, prog->regstclass, s, endpos, startpos, 1);
        if (!s) {
 #ifdef DEBUGGING
@@ -694,30 +739,55 @@ Perl_re_intuit_start(pTHX_ regexp *prog, SV *sv, char *strpos,
                                "Could not match STCLASS...\n") );
                goto fail;
            }
+           DEBUG_r( PerlIO_printf(Perl_debug_log,
+                                  "This position contradicts STCLASS...\n") );
+           if ((prog->reganch & ROPT_ANCH) && !ml_anch)
+               goto fail;
            /* Contradict one of substrings */
            if (prog->anchored_substr) {
-               DEBUG_r( PerlIO_printf(Perl_debug_log,
-                               "This position contradicts STCLASS...\n") );
                if (prog->anchored_substr == check) {
                    DEBUG_r( what = "anchored" );
                  hop_and_restart:
                    PL_regeol = strend; /* Used in HOP() */
                    s = HOPc(t, 1);
+                   if (s + start_shift + end_shift > strend) {
+                       /* XXXX Should be taken into account earlier? */
+                       DEBUG_r( PerlIO_printf(Perl_debug_log,
+                                              "Could not match STCLASS...\n") );
+                       goto fail;
+                   }
+                   if (!check)
+                       goto giveup;
                    DEBUG_r( PerlIO_printf(Perl_debug_log,
-                               "trying %s substr starting at offset %ld...\n",
+                               "Looking for %s substr starting at offset %ld...\n",
                                 what, (long)(s + start_shift - i_strpos)) );
                    goto restart;
                }
-               /* Have both, check is floating */
+               /* Have both, check_string is floating */
                if (t + start_shift >= check_at) /* Contradicts floating=check */
                    goto retry_floating_check;
                /* Recheck anchored substring, but not floating... */
                s = check_at; 
+               if (!check)
+                   goto giveup;
                DEBUG_r( PerlIO_printf(Perl_debug_log,
-                         "trying anchored substr starting at offset %ld...\n",
+                         "Looking for anchored substr starting at offset %ld...\n",
                          (long)(other_last - i_strpos)) );
                goto do_other_anchored;
            }
+           /* Another way we could have checked stclass at the
+               current position only: */
+           if (ml_anch) {
+               s = t = t + 1;
+               if (!check)
+                   goto giveup;
+               DEBUG_r( PerlIO_printf(Perl_debug_log,
+                         "Looking for /%s^%s/m starting at offset %ld...\n",
+                         PL_colors[0],PL_colors[1], (long)(t - i_strpos)) );
+               goto try_at_offset;
+           }
+           if (!prog->float_substr)    /* Could have been deleted */
+               goto fail;
            /* Check is floating subtring. */
          retry_floating_check:
            t = check_at - start_shift;
@@ -732,12 +802,15 @@ Perl_re_intuit_start(pTHX_ regexp *prog, SV *sv, char *strpos,
                     PerlIO_printf(Perl_debug_log, 
                        "Does not contradict STCLASS...\n") );
     }
-    DEBUG_r(PerlIO_printf(Perl_debug_log, "%sGuessed:%s match at offset %ld\n",
-                         PL_colors[4], PL_colors[5], (long)(s - i_strpos)) );
+  giveup:
+    DEBUG_r(PerlIO_printf(Perl_debug_log, "%s%s:%s match at offset %ld\n",
+                         PL_colors[4], (check ? "Guessed" : "Giving up"),
+                         PL_colors[5], (long)(s - i_strpos)) );
     return s;
 
   fail_finish:                         /* Substring not found */
-    BmUSEFUL(prog->check_substr) += 5; /* hooray */
+    if (prog->check_substr)            /* could be removed already */
+       BmUSEFUL(prog->check_substr) += 5; /* hooray */
   fail:
     DEBUG_r(PerlIO_printf(Perl_debug_log, "%sMatch rejected by optimizer%s\n",
                          PL_colors[4],PL_colors[5]));
@@ -745,14 +818,14 @@ Perl_re_intuit_start(pTHX_ regexp *prog, SV *sv, char *strpos,
 }
 
 /* We know what class REx starts with.  Try to find this position... */
-static char *
-find_byclass(regexp * prog, regnode *c, char *s, char *strend, char *startpos, I32 norun)
+STATIC char *
+S_find_byclass(pTHX_ regexp * prog, regnode *c, char *s, char *strend, char *startpos, I32 norun)
 {
        I32 doevery = (prog->reganch & ROPT_SKIP) == 0;
        char *m;
-       int ln;
-       int c1;
-       int c2;
+       STRLEN ln;
+       unsigned int c1;
+       unsigned int c2;
        char *e;
        register I32 tmp = 1;   /* Scratch variable? */
 
@@ -773,7 +846,7 @@ find_byclass(regexp * prog, regnode *c, char *s, char *strend, char *startpos, I
            break;
        case ANYOF:
            while (s < strend) {
-               if (REGINCLASS(c, *s)) {
+               if (REGINCLASS(c, *(U8*)s)) {
                    if (tmp && (norun || regtry(prog, s)))
                        goto got_it;
                    else
@@ -787,13 +860,13 @@ find_byclass(regexp * prog, regnode *c, char *s, char *strend, char *startpos, I
        case EXACTF:
            m = STRING(c);
            ln = STR_LEN(c);
-           c1 = *m;
+           c1 = *(U8*)m;
            c2 = PL_fold[c1];
            goto do_exactf;
        case EXACTFL:
            m = STRING(c);
            ln = STR_LEN(c);
-           c1 = *m;
+           c1 = *(U8*)m;
            c2 = PL_fold_locale[c1];
          do_exactf:
            e = strend - ln;
@@ -803,20 +876,20 @@ find_byclass(regexp * prog, regnode *c, char *s, char *strend, char *startpos, I
            /* Here it is NOT UTF!  */
            if (c1 == c2) {
                while (s <= e) {
-                   if ( *s == c1
-                        && (ln == 1 || (OP(c) == EXACTF
-                                        ? ibcmp(s, m, ln)
-                                        : ibcmp_locale(s, m, ln)))
+                   if ( *(U8*)s == c1
+                        && (ln == 1 || !(OP(c) == EXACTF
+                                         ? ibcmp(s, m, ln)
+                                         : ibcmp_locale(s, m, ln)))
                         && (norun || regtry(prog, s)) )
                        goto got_it;
                    s++;
                }
            } else {
                while (s <= e) {
-                   if ( (*s == c1 || *s == c2)
-                        && (ln == 1 || (OP(c) == EXACTF
-                                        ? ibcmp(s, m, ln)
-                                        : ibcmp_locale(s, m, ln)))
+                   if ( (*(U8*)s == c1 || *(U8*)s == c2)
+                        && (ln == 1 || !(OP(c) == EXACTF
+                                         ? ibcmp(s, m, ln)
+                                         : ibcmp_locale(s, m, ln)))
                         && (norun || regtry(prog, s)) )
                        goto got_it;
                    s++;
@@ -844,10 +917,17 @@ find_byclass(regexp * prog, regnode *c, char *s, char *strend, char *startpos, I
            PL_reg_flags |= RF_tainted;
            /* FALL THROUGH */
        case BOUNDUTF8:
-           tmp = (I32)(s != startpos) ? utf8_to_uv(reghop((U8*)s, -1), 0) : '\n';
-           tmp = ((OP(c) == BOUND ? isALNUM_uni(tmp) : isALNUM_LC_uni(tmp)) != 0);
+           if (s == startpos)
+               tmp = '\n';
+           else {
+               U8 *r = reghop((U8*)s, -1);
+
+               tmp = (I32)utf8_to_uv(r, s - (char*)r, 0, 0);
+           }
+           tmp = ((OP(c) == BOUNDUTF8 ?
+                   isALNUM_uni(tmp) : isALNUM_LC_uni(tmp)) != 0);
            while (s < strend) {
-               if (tmp == !(OP(c) == BOUND ?
+               if (tmp == !(OP(c) == BOUNDUTF8 ?
                             swash_fetch(PL_utf8_alnum, (U8*)s) :
                             isALNUM_LC_utf8((U8*)s)))
                {
@@ -880,12 +960,17 @@ find_byclass(regexp * prog, regnode *c, char *s, char *strend, char *startpos, I
            PL_reg_flags |= RF_tainted;
            /* FALL THROUGH */
        case NBOUNDUTF8:
-           if (prog->minlen)
-               strend = reghop_c(strend, -1);
-           tmp = (I32)(s != startpos) ? utf8_to_uv(reghop((U8*)s, -1), 0) : '\n';
-           tmp = ((OP(c) == NBOUND ? isALNUM_uni(tmp) : isALNUM_LC_uni(tmp)) != 0);
+           if (s == startpos)
+               tmp = '\n';
+           else {
+               U8 *r = reghop((U8*)s, -1);
+
+               tmp = (I32)utf8_to_uv(r, s - (char*)r, 0, 0);
+           }
+           tmp = ((OP(c) == NBOUNDUTF8 ?
+                   isALNUM_uni(tmp) : isALNUM_LC_uni(tmp)) != 0);
            while (s < strend) {
-               if (tmp == !(OP(c) == NBOUND ?
+               if (tmp == !(OP(c) == NBOUNDUTF8 ?
                             swash_fetch(PL_utf8_alnum, (U8*)s) :
                             isALNUM_LC_utf8((U8*)s)))
                    tmp = !tmp;
@@ -1221,11 +1306,8 @@ find_byclass(regexp * prog, regnode *c, char *s, char *strend, char *startpos, I
            }
            break;
        default:
-           {
-               dTHX;
-               Perl_croak(aTHX_ "panic: unknown regstclass %d", (int)OP(c));
-               break;
-           }
+           Perl_croak(aTHX_ "panic: unknown regstclass %d", (int)OP(c));
+           break;
        }
        return 0;
       got_it:
@@ -1248,10 +1330,9 @@ Perl_regexec_flags(pTHX_ register regexp *prog, char *stringarg, register char *
     register char *s;
     register regnode *c;
     register char *startpos = stringarg;
-    register I32 tmp;
     I32 minlen;                /* must match at least this many chars */
     I32 dontbother = 0;        /* how many characters not to try at end */
-    I32 start_shift = 0;               /* Offset of the start to find
+    /* I32 start_shift = 0; */         /* Offset of the start to find
                                         constant substr. */            /* CC */
     I32 end_shift = 0;                 /* Same for the end. */         /* CC */
     I32 scream_pos = -1;               /* Internal iterator of scream. */
@@ -1407,9 +1488,14 @@ Perl_regexec_flags(pTHX_ register regexp *prog, char *stringarg, register char *
        /* we have /x+whatever/ */
        /* it must be a one character string (XXXX Except UTF?) */
        char ch = SvPVX(prog->anchored_substr)[0];
+#ifdef DEBUGGING
+       int did_match = 0;
+#endif
+
        if (UTF) {
            while (s < strend) {
                if (*s == ch) {
+                   DEBUG_r( did_match = 1 );
                    if (regtry(prog, s)) goto got_it;
                    s += UTF8SKIP(s);
                    while (s < strend && *s == ch)
@@ -1421,6 +1507,7 @@ Perl_regexec_flags(pTHX_ register regexp *prog, char *stringarg, register char *
        else {
            while (s < strend) {
                if (*s == ch) {
+                   DEBUG_r( did_match = 1 );
                    if (regtry(prog, s)) goto got_it;
                    s++;
                    while (s < strend && *s == ch)
@@ -1429,6 +1516,9 @@ Perl_regexec_flags(pTHX_ register regexp *prog, char *stringarg, register char *
                s++;
            }
        }
+       DEBUG_r(did_match ||
+               PerlIO_printf(Perl_debug_log,
+                             "Did not find anchored character...\n"));
     }
     /*SUPPRESS 560*/
     else if (prog->anchored_substr != Nullsv
@@ -1440,11 +1530,13 @@ Perl_regexec_flags(pTHX_ register regexp *prog, char *stringarg, register char *
            prog->anchored_substr ? prog->anchored_offset : prog->float_max_offset;
        I32 back_min = 
            prog->anchored_substr ? prog->anchored_offset : prog->float_min_offset;
-       I32 delta = back_max - back_min;
        char *last = HOPc(strend,       /* Cannot start after this */
                          -(I32)(CHR_SVLEN(must)
                                 - (SvTAIL(must) != 0) + back_min));
        char *last1;            /* Last position checked before */
+#ifdef DEBUGGING
+       int did_match = 0;
+#endif
 
        if (s > PL_bostr)
            last1 = HOPc(s, -1);
@@ -1463,6 +1555,7 @@ Perl_regexec_flags(pTHX_ register regexp *prog, char *stringarg, register char *
                 : (s = fbm_instr((unsigned char*)HOP(s, back_min),
                                  (unsigned char*)strend, must, 
                                  PL_multiline ? FBMrf_MULTILINE : 0))) ) {
+           DEBUG_r( did_match = 1 );
            if (HOPc(s, -back_max) > last1) {
                last1 = HOPc(s, -back_min);
                s = HOPc(s, -back_max);
@@ -1488,19 +1581,28 @@ Perl_regexec_flags(pTHX_ register regexp *prog, char *stringarg, register char *
                }
            }
        }
+       DEBUG_r(did_match ||
+               PerlIO_printf(Perl_debug_log, "Did not find %s substr `%s%.*s%s'%s...\n",
+                             ((must == prog->anchored_substr)
+                              ? "anchored" : "floating"),
+                             PL_colors[0],
+                             (int)(SvCUR(must) - (SvTAIL(must)!=0)),
+                             SvPVX(must),
+                             PL_colors[1], (SvTAIL(must) ? "$" : "")));
        goto phooey;
     }
-    else if (c = prog->regstclass) {
-       if (minlen)             /* don't bother with what can't match */
+    else if ((c = prog->regstclass)) {
+       if (minlen && PL_regkind[(U8)OP(prog->regstclass)] != EXACT)
+           /* don't bother with what can't match */
            strend = HOPc(strend, -(minlen - 1));
        if (find_byclass(prog, c, s, strend, startpos, 0))
            goto got_it;
+       DEBUG_r(PerlIO_printf(Perl_debug_log, "Contradicts stclass...\n"));
     }
     else {
        dontbother = 0;
        if (prog->float_substr != Nullsv) {     /* Trim the end. */
            char *last;
-           I32 oldpos = scream_pos;
 
            if (flags & REXEC_SCREAM) {
                last = screaminstr(sv, prog->float_substr, s - strbeg,
@@ -1528,7 +1630,12 @@ Perl_regexec_flags(pTHX_ register regexp *prog, char *stringarg, register char *
                        last = strend;  /* matching `$' */
                }
            }
-           if (last == NULL) goto phooey; /* Should not happen! */
+           if (last == NULL) {
+               DEBUG_r(PerlIO_printf(Perl_debug_log,
+                                     "%sCan't trim the tail, match fails (should not happen)%s\n",
+                                     PL_colors[4],PL_colors[5]));
+               goto phooey; /* Should not happen! */
+           }
            dontbother = strend - last + prog->float_min_offset;
        }
        if (minlen && (dontbother < minlen))
@@ -1590,6 +1697,8 @@ got_it:
     return 1;
 
 phooey:
+    DEBUG_r(PerlIO_printf(Perl_debug_log, "%sMatch failed%s\n",
+                         PL_colors[4],PL_colors[5]));
     if (PL_reg_eval_set)
        restore_pos(aTHXo_ 0);
     return 0;
@@ -1607,6 +1716,9 @@ S_regtry(pTHX_ regexp *prog, char *startpos)
     register I32 *ep;
     CHECKPOINT lastcp;
 
+#ifdef DEBUGGING
+    PL_regindent = 0;  /* XXXX Not good when matches are reenterable... */
+#endif
     if ((prog->reganch & ROPT_EVAL_SEEN) && !PL_reg_eval_set) {
        MAGIC *mg;
 
@@ -1615,12 +1727,12 @@ S_regtry(pTHX_ regexp *prog, char *startpos)
            PerlIO_printf(Perl_debug_log, "  setting stack tmpbase at %"IVdf"\n",
                          (IV)(PL_stack_sp - PL_stack_base));
            ));
-       SAVEINT(cxstack[cxstack_ix].blk_oldsp);
+       SAVEI32(cxstack[cxstack_ix].blk_oldsp);
        cxstack[cxstack_ix].blk_oldsp = PL_stack_sp - PL_stack_base;
        /* Otherwise OP_NEXTSTATE will free whatever on stack now.  */
        SAVETMPS;
        /* Apparently this is not needed, judging by wantarray. */
-       /* SAVEINT(cxstack[cxstack_ix].blk_gimme);
+       /* SAVEI8(cxstack[cxstack_ix].blk_gimme);
           cxstack[cxstack_ix].blk_gimme = G_SCALAR; */
 
        if (PL_reg_sv) {
@@ -1643,7 +1755,7 @@ S_regtry(pTHX_ regexp *prog, char *startpos)
            SAVEDESTRUCTOR_X(restore_pos, 0);
         }
        if (!PL_reg_curpm)
-           New(22,PL_reg_curpm, 1, PMOP);
+           Newz(22,PL_reg_curpm, 1, PMOP);
        PL_reg_curpm->op_pmregexp = prog;
        PL_reg_oldcurpm = PL_curpm;
        PL_curpm = PL_reg_curpm;
@@ -1678,7 +1790,8 @@ S_regtry(pTHX_ regexp *prog, char *startpos)
 
     /* XXXX What this code is doing here?!!!  There should be no need
        to do this again and again, PL_reglastparen should take care of
-       this!  */
+       this!  --ilya*/
+    /* Tests pat.t#187 and split.t#{13,14} seem to depend on this. --jhi */
     sp = prog->startp;
     ep = prog->endp;
     if (prog->nparens) {
@@ -1687,15 +1800,45 @@ S_regtry(pTHX_ regexp *prog, char *startpos)
            *++ep = -1;
        }
     }
-    REGCP_SET;
+    REGCP_SET(lastcp);
     if (regmatch(prog->program + 1)) {
        prog->endp[0] = PL_reginput - PL_bostr;
        return 1;
     }
-    REGCP_UNWIND;
+    REGCP_UNWIND(lastcp);
     return 0;
 }
 
+#define RE_UNWIND_BRANCH       1
+#define RE_UNWIND_BRANCHJ      2
+
+union re_unwind_t;
+
+typedef struct {               /* XX: makes sense to enlarge it... */
+    I32 type;
+    I32 prev;
+    CHECKPOINT lastcp;
+} re_unwind_generic_t;
+
+typedef struct {
+    I32 type;
+    I32 prev;
+    CHECKPOINT lastcp;
+    I32 lastparen;
+    regnode *next;
+    char *locinput;
+    I32 nextchr;
+#ifdef DEBUGGING
+    int regindent;
+#endif
+} re_unwind_branch_t;
+
+typedef union re_unwind_t {
+    I32 type;
+    re_unwind_generic_t generic;
+    re_unwind_branch_t branch;
+} re_unwind_t;
+
 /*
  - regmatch - main matching routine
  *
@@ -1725,6 +1868,9 @@ S_regmatch(pTHX_ regnode *prog)
     register char *locinput = PL_reginput;
     register I32 c1, c2, paren;        /* case fold search, parenth */
     int minmod = 0, sw = 0, logical = 0;
+    I32 unwind = 0;
+    I32 firstcp = PL_savestack_ix;
+
 #ifdef DEBUGGING
     PL_regindent++;
 #endif
@@ -1734,7 +1880,7 @@ S_regmatch(pTHX_ regnode *prog)
     scan = prog;
     while (scan != NULL) {
 #define sayNO_L (logical ? (logical = 0, sw = 0, goto cont) : sayNO)
-#ifdef DEBUGGING
+#if 1
 #  define sayYES goto yes
 #  define sayNO goto no
 #  define sayYES_FINAL goto yes_final
@@ -1814,7 +1960,7 @@ S_regmatch(pTHX_ regnode *prog)
            }
            sayNO;
        case SBOL:
-           if (locinput == PL_regbol && PL_regprev == '\n')
+           if (locinput == PL_bostr)
                break;
            sayNO;
        case GPOS:
@@ -1867,12 +2013,12 @@ S_regmatch(pTHX_ regnode *prog)
                nextchr = UCHARAT(locinput);
                break;
            }
-           if (!nextchr && locinput >= PL_regeol || nextchr == '\n')
+           if ((!nextchr && locinput >= PL_regeol) || nextchr == '\n')
                sayNO;
            nextchr = UCHARAT(++locinput);
            break;
        case REG_ANY:
-           if (!nextchr && locinput >= PL_regeol || nextchr == '\n')
+           if ((!nextchr && locinput >= PL_regeol) || nextchr == '\n')
                sayNO;
            nextchr = UCHARAT(++locinput);
            break;
@@ -1903,9 +2049,10 @@ S_regmatch(pTHX_ regnode *prog)
                while (s < e) {
                    if (l >= PL_regeol)
                        sayNO;
-                   if (utf8_to_uv((U8*)s, 0) != (c1 ?
-                                                 toLOWER_utf8((U8*)l) :
-                                                 toLOWER_LC_utf8((U8*)l)))
+                   if (utf8_to_uv((U8*)s, e - s, 0, 0) !=
+                       (c1 ?
+                        toLOWER_utf8((U8*)l) :
+                        toLOWER_LC_utf8((U8*)l)))
                    {
                        sayNO;
                    }
@@ -2040,8 +2187,13 @@ S_regmatch(pTHX_ regnode *prog)
        case BOUNDUTF8:
        case NBOUNDUTF8:
            /* was last char in word? */
-           ln = (locinput != PL_regbol)
-               ? utf8_to_uv(reghop((U8*)locinput, -1), 0) : PL_regprev;
+           if (locinput == PL_regbol)
+               ln = PL_regprev;
+           else {
+               U8 *r = reghop((U8*)locinput, -1);
+
+               ln = utf8_to_uv(r, s - (char*)r, 0, 0);
+           }
            if (OP(scan) == BOUNDUTF8 || OP(scan) == NBOUNDUTF8) {
                ln = isALNUM_uni(ln);
                n = swash_fetch(PL_utf8_alnum, (U8*)locinput);
@@ -2057,7 +2209,7 @@ S_regmatch(pTHX_ regnode *prog)
            PL_reg_flags |= RF_tainted;
            /* FALL THROUGH */
        case SPACE:
-           if (!nextchr && locinput >= PL_regeol)
+           if (!nextchr)
                sayNO;
            if (!(OP(scan) == SPACE
                  ? isSPACE(nextchr) : isSPACE_LC(nextchr)))
@@ -2068,11 +2220,11 @@ S_regmatch(pTHX_ regnode *prog)
            PL_reg_flags |= RF_tainted;
            /* FALL THROUGH */
        case SPACEUTF8:
-           if (!nextchr && locinput >= PL_regeol)
+           if (!nextchr)
                sayNO;
            if (nextchr & 0x80) {
                if (!(OP(scan) == SPACEUTF8
-                     ? swash_fetch(PL_utf8_space,(U8*)locinput)
+                     ? swash_fetch(PL_utf8_space, (U8*)locinput)
                      : isSPACE_LC_utf8((U8*)locinput)))
                {
                    sayNO;
@@ -2090,9 +2242,9 @@ S_regmatch(pTHX_ regnode *prog)
            PL_reg_flags |= RF_tainted;
            /* FALL THROUGH */
        case NSPACE:
-           if (!nextchr)
+           if (!nextchr && locinput >= PL_regeol)
                sayNO;
-           if (OP(scan) == SPACE
+           if (OP(scan) == NSPACE
                ? isSPACE(nextchr) : isSPACE_LC(nextchr))
                sayNO;
            nextchr = UCHARAT(++locinput);
@@ -2101,11 +2253,11 @@ S_regmatch(pTHX_ regnode *prog)
            PL_reg_flags |= RF_tainted;
            /* FALL THROUGH */
        case NSPACEUTF8:
-           if (!nextchr)
+           if (!nextchr && locinput >= PL_regeol)
                sayNO;
            if (nextchr & 0x80) {
                if (OP(scan) == NSPACEUTF8
-                   ? swash_fetch(PL_utf8_space,(U8*)locinput)
+                   ? swash_fetch(PL_utf8_space, (U8*)locinput)
                    : isSPACE_LC_utf8((U8*)locinput))
                {
                    sayNO;
@@ -2123,7 +2275,7 @@ S_regmatch(pTHX_ regnode *prog)
            PL_reg_flags |= RF_tainted;
            /* FALL THROUGH */
        case DIGIT:
-           if (!nextchr && locinput >= PL_regeol)
+           if (!nextchr)
                sayNO;
            if (!(OP(scan) == DIGIT
                  ? isDIGIT(nextchr) : isDIGIT_LC(nextchr)))
@@ -2137,9 +2289,9 @@ S_regmatch(pTHX_ regnode *prog)
            if (!nextchr)
                sayNO;
            if (nextchr & 0x80) {
-               if (OP(scan) == NDIGITUTF8
-                   ? swash_fetch(PL_utf8_digit,(U8*)locinput)
-                   : isDIGIT_LC_utf8((U8*)locinput))
+               if (!(OP(scan) == DIGITUTF8
+                     ? swash_fetch(PL_utf8_digit, (U8*)locinput)
+                     : isDIGIT_LC_utf8((U8*)locinput)))
                {
                    sayNO;
                }
@@ -2147,7 +2299,8 @@ S_regmatch(pTHX_ regnode *prog)
                nextchr = UCHARAT(locinput);
                break;
            }
-           if (!isDIGIT(nextchr))
+           if (!(OP(scan) == DIGITUTF8
+                 ? isDIGIT(nextchr) : isDIGIT_LC(nextchr)))
                sayNO;
            nextchr = UCHARAT(++locinput);
            break;
@@ -2155,9 +2308,9 @@ S_regmatch(pTHX_ regnode *prog)
            PL_reg_flags |= RF_tainted;
            /* FALL THROUGH */
        case NDIGIT:
-           if (!nextchr)
+           if (!nextchr && locinput >= PL_regeol)
                sayNO;
-           if (OP(scan) == DIGIT
+           if (OP(scan) == NDIGIT
                ? isDIGIT(nextchr) : isDIGIT_LC(nextchr))
                sayNO;
            nextchr = UCHARAT(++locinput);
@@ -2169,13 +2322,18 @@ S_regmatch(pTHX_ regnode *prog)
            if (!nextchr && locinput >= PL_regeol)
                sayNO;
            if (nextchr & 0x80) {
-               if (swash_fetch(PL_utf8_digit,(U8*)locinput))
+               if (OP(scan) == NDIGITUTF8
+                   ? swash_fetch(PL_utf8_digit, (U8*)locinput)
+                   : isDIGIT_LC_utf8((U8*)locinput))
+               {
                    sayNO;
+               }
                locinput += PL_utf8skip[nextchr];
                nextchr = UCHARAT(locinput);
                break;
            }
-           if (isDIGIT(nextchr))
+           if (OP(scan) == NDIGITUTF8
+               ? isDIGIT(nextchr) : isDIGIT_LC(nextchr))
                sayNO;
            nextchr = UCHARAT(++locinput);
            break;
@@ -2308,6 +2466,7 @@ S_regmatch(pTHX_ regnode *prog)
                        I32 onpar = PL_regnpar;
 
                        pm.op_pmflags = 0;
+                       pm.op_pmdynflags = (UTF||DO_UTF8(ret) ? PMdf_UTF8 : 0);
                        re = CALLREGCOMP(aTHX_ t, t + len, &pm);
                        if (!(SvFLAGS(ret) 
                              & (SVs_TEMP | SVs_PADTMP | SVf_READONLY)))
@@ -2332,7 +2491,7 @@ S_regmatch(pTHX_ regnode *prog)
                    PL_regcc = 0;
                    
                    cp = regcppush(0);  /* Save *all* the positions. */
-                   REGCP_SET;
+                   REGCP_SET(lastcp);
                    cache_re(re);
                    state.ss = PL_savestack_ix;
                    *PL_reglastparen = 0;
@@ -2362,7 +2521,7 @@ S_regmatch(pTHX_ regnode *prog)
                        sayYES;
                    }
                    ReREFCNT_dec(re);
-                   REGCP_UNWIND;
+                   REGCP_UNWIND(lastcp);
                    regcppop();
                    PL_reg_call_cc = state.prev;
                    PL_regcc = state.cc;
@@ -2489,12 +2648,18 @@ S_regmatch(pTHX_ regnode *prog)
        case CURLYX: {
                CURCUR cc;
                CHECKPOINT cp = PL_savestack_ix;
+               /* No need to save/restore up to this paren */
+               I32 parenfloor = scan->flags;
 
                if (OP(PREVOPER(next)) == NOTHING) /* LONGJMP */
                    next += ARG(next);
                cc.oldcc = PL_regcc;
                PL_regcc = &cc;
-               cc.parenfloor = *PL_reglastparen;
+               /* XXXX Probably it is better to teach regpush to support
+                  parenfloor > PL_regsize... */
+               if (parenfloor > *PL_reglastparen)
+                   parenfloor = *PL_reglastparen; /* Pessimization... */
+               cc.parenfloor = parenfloor;
                cc.cur = -1;
                cc.min = ARG1(scan);
                cc.max  = ARG2(scan);
@@ -2617,22 +2782,22 @@ S_regmatch(pTHX_ regnode *prog)
                    if (PL_regcc)
                        ln = PL_regcc->cur;
                    cp = regcppush(cc->parenfloor);
-                   REGCP_SET;
+                   REGCP_SET(lastcp);
                    if (regmatch(cc->next)) {
                        regcpblow(cp);
                        sayYES; /* All done. */
                    }
-                   REGCP_UNWIND;
+                   REGCP_UNWIND(lastcp);
                    regcppop();
                    if (PL_regcc)
                        PL_regcc->cur = ln;
                    PL_regcc = cc;
 
                    if (n >= cc->max) { /* Maximum greed exceeded? */
-                       if (ckWARN(WARN_UNSAFE) && n >= REG_INFTY 
+                       if (ckWARN(WARN_REGEXP) && n >= REG_INFTY 
                            && !(PL_reg_flags & RF_warned)) {
                            PL_reg_flags |= RF_warned;
-                           Perl_warner(aTHX_ WARN_UNSAFE, "%s limit (%d) exceeded",
+                           Perl_warner(aTHX_ WARN_REGEXP, "%s limit (%d) exceeded",
                                 "Complex regular subexpression recursion",
                                 REG_INFTY - 1);
                        }
@@ -2649,12 +2814,12 @@ S_regmatch(pTHX_ regnode *prog)
                    cc->cur = n;
                    cc->lastloc = locinput;
                    cp = regcppush(cc->parenfloor);
-                   REGCP_SET;
+                   REGCP_SET(lastcp);
                    if (regmatch(cc->scan)) {
                        regcpblow(cp);
                        sayYES;
                    }
-                   REGCP_UNWIND;
+                   REGCP_UNWIND(lastcp);
                    regcppop();
                    cc->cur = n - 1;
                    cc->lastloc = lastloc;
@@ -2667,12 +2832,12 @@ S_regmatch(pTHX_ regnode *prog)
                    cp = regcppush(cc->parenfloor);
                    cc->cur = n;
                    cc->lastloc = locinput;
-                   REGCP_SET;
+                   REGCP_SET(lastcp);
                    if (regmatch(cc->scan)) {
                        regcpblow(cp);
                        sayYES;
                    }
-                   REGCP_UNWIND;
+                   REGCP_UNWIND(lastcp);
                    regcppop();         /* Restore some previous $<digit>s? */
                    PL_reginput = locinput;
                    DEBUG_r(
@@ -2681,10 +2846,10 @@ S_regmatch(pTHX_ regnode *prog)
                                      REPORT_CODE_OFF+PL_regindent*2, "")
                        );
                }
-               if (ckWARN(WARN_UNSAFE) && n >= REG_INFTY 
+               if (ckWARN(WARN_REGEXP) && n >= REG_INFTY 
                        && !(PL_reg_flags & RF_warned)) {
                    PL_reg_flags |= RF_warned;
-                   Perl_warner(aTHX_ WARN_UNSAFE, "%s limit (%d) exceeded",
+                   Perl_warner(aTHX_ WARN_REGEXP, "%s limit (%d) exceeded",
                         "Complex regular subexpression recursion",
                         REG_INFTY - 1);
                }
@@ -2718,30 +2883,30 @@ S_regmatch(pTHX_ regnode *prog)
                if (OP(next) != c1)     /* No choice. */
                    next = inner;       /* Avoid recursion. */
                else {
-                   int lastparen = *PL_reglastparen;
+                   I32 lastparen = *PL_reglastparen;
+                   I32 unwind1;
+                   re_unwind_branch_t *uw;
+
+                   /* Put unwinding data on stack */
+                   unwind1 = SSNEWt(1,re_unwind_branch_t);
+                   uw = SSPTRt(unwind1,re_unwind_branch_t);
+                   uw->prev = unwind;
+                   unwind = unwind1;
+                   uw->type = ((c1 == BRANCH)
+                               ? RE_UNWIND_BRANCH
+                               : RE_UNWIND_BRANCHJ);
+                   uw->lastparen = lastparen;
+                   uw->next = next;
+                   uw->locinput = locinput;
+                   uw->nextchr = nextchr;
+#ifdef DEBUGGING
+                   uw->regindent = ++PL_regindent;
+#endif
 
-                   REGCP_SET;
-                   do {
-                       PL_reginput = locinput;
-                       if (regmatch(inner))
-                           sayYES;
-                       REGCP_UNWIND;
-                       for (n = *PL_reglastparen; n > lastparen; n--)
-                           PL_regendp[n] = -1;
-                       *PL_reglastparen = n;
-                       scan = next;
-                       /*SUPPRESS 560*/
-                       if (n = (c1 == BRANCH ? NEXT_OFF(next) : ARG(next)))
-                           next += n;
-                       else
-                           next = NULL;
-                       inner = NEXTOPER(scan);
-                       if (c1 == BRANCHJ) {
-                           inner = NEXTOPER(inner);
-                       }
-                   } while (scan != NULL && OP(scan) == c1);
-                   sayNO;
-                   /* NOTREACHED */
+                   REGCP_SET(uw->lastcp);
+
+                   /* Now go into the first branch */
+                   next = inner;
                }
            }
            break;
@@ -2791,7 +2956,7 @@ S_regmatch(pTHX_ regnode *prog)
                }
                else
                    c1 = c2 = -1000;
-               REGCP_SET;
+               REGCP_SET(lastcp);
                /* This may be improved if l == 0.  */
                while (n >= ln || (n == REG_INFTY && ln > 0 && l)) { /* ln overflow ? */
                    /* If it could work, try it. */
@@ -2810,7 +2975,7 @@ S_regmatch(pTHX_ regnode *prog)
                        }
                        if (regmatch(next))
                            sayYES;
-                       REGCP_UNWIND;
+                       REGCP_UNWIND(lastcp);
                    }
                    /* Couldn't or didn't -- move forward. */
                    PL_reginput = locinput;
@@ -2850,7 +3015,7 @@ S_regmatch(pTHX_ regnode *prog)
                    else
                        c1 = c2 = -1000;
                }
-               REGCP_SET;
+               REGCP_SET(lastcp);
                while (n >= ln) {
                    /* If it could work, try it. */
                    if (c1 == -1000 ||
@@ -2872,7 +3037,7 @@ S_regmatch(pTHX_ regnode *prog)
                        }
                        if (regmatch(next))
                            sayYES;
-                       REGCP_UNWIND;
+                       REGCP_UNWIND(lastcp);
                    }
                    /* Couldn't or didn't -- back up. */
                    n--;
@@ -2933,7 +3098,7 @@ S_regmatch(pTHX_ regnode *prog)
                if (ln && regrepeat(scan, ln) < ln)
                    sayNO;
                locinput = PL_reginput;
-               REGCP_SET;
+               REGCP_SET(lastcp);
                if (c1 != -1000) {
                    char *e = locinput + n - ln; /* Should not check after this */
                    char *old = locinput;
@@ -2961,18 +3126,9 @@ S_regmatch(pTHX_ regnode *prog)
                                sayNO;
                        }
                        /* PL_reginput == locinput now */
-                       if (paren) {
-                           if (ln) {
-                               PL_regstartp[paren] = HOPc(locinput, -1) - PL_bostr;
-                               PL_regendp[paren] = locinput - PL_bostr;
-                           }
-                           else
-                               PL_regendp[paren] = -1;
-                       }
-                       if (regmatch(next))
-                           sayYES;
+                       TRYPAREN(paren, ln, locinput);
                        PL_reginput = locinput; /* Could be reset... */
-                       REGCP_UNWIND;
+                       REGCP_UNWIND(lastcp);
                        /* Couldn't or didn't -- move forward. */
                        old = locinput++;
                    }
@@ -2984,17 +3140,8 @@ S_regmatch(pTHX_ regnode *prog)
                        UCHARAT(PL_reginput) == c1 ||
                        UCHARAT(PL_reginput) == c2)
                    {
-                       if (paren) {
-                           if (n) {
-                               PL_regstartp[paren] = HOPc(PL_reginput, -1) - PL_bostr;
-                               PL_regendp[paren] = PL_reginput - PL_bostr;
-                           }
-                           else
-                               PL_regendp[paren] = -1;
-                       }
-                       if (regmatch(next))
-                           sayYES;
-                       REGCP_UNWIND;
+                       TRYPAREN(paren, n, PL_reginput);
+                       REGCP_UNWIND(lastcp);
                    }
                    /* Couldn't or didn't -- move forward. */
                    PL_reginput = locinput;
@@ -3011,9 +3158,15 @@ S_regmatch(pTHX_ regnode *prog)
                n = regrepeat(scan, n);
                locinput = PL_reginput;
                if (ln < n && PL_regkind[(U8)OP(next)] == EOL &&
-                   (!PL_multiline  || OP(next) == SEOL))
+                   (!PL_multiline  || OP(next) == SEOL || OP(next) == EOS)) {
                    ln = n;                     /* why back off? */
-               REGCP_SET;
+                   /* ...because $ and \Z can match before *and* after
+                      newline at the end.  Consider "\n\n" =~ /\n+\Z\n/.
+                      We should back off by one in this case. */
+                   if (UCHARAT(PL_reginput - 1) == '\n' && OP(next) != EOS)
+                       ln--;
+               }
+               REGCP_SET(lastcp);
                if (paren) {
                    while (n >= ln) {
                        /* If it could work, try it. */
@@ -3021,17 +3174,8 @@ S_regmatch(pTHX_ regnode *prog)
                            UCHARAT(PL_reginput) == c1 ||
                            UCHARAT(PL_reginput) == c2)
                            {
-                               if (paren && n) {
-                                   if (n) {
-                                       PL_regstartp[paren] = HOPc(PL_reginput, -1) - PL_bostr;
-                                       PL_regendp[paren] = PL_reginput - PL_bostr;
-                                   }
-                                   else
-                                       PL_regendp[paren] = -1;
-                               }
-                               if (regmatch(next))
-                                   sayYES;
-                               REGCP_UNWIND;
+                               TRYPAREN(paren, n, PL_reginput);
+                               REGCP_UNWIND(lastcp);
                            }
                        /* Couldn't or didn't -- back up. */
                        n--;
@@ -3045,9 +3189,8 @@ S_regmatch(pTHX_ regnode *prog)
                            UCHARAT(PL_reginput) == c1 ||
                            UCHARAT(PL_reginput) == c2)
                            {
-                               if (regmatch(next))
-                                   sayYES;
-                               REGCP_UNWIND;
+                               TRYPAREN(paren, n, PL_reginput);
+                               REGCP_UNWIND(lastcp);
                            }
                        /* Couldn't or didn't -- back up. */
                        n--;
@@ -3065,7 +3208,7 @@ S_regmatch(pTHX_ regnode *prog)
                CHECKPOINT cp, lastcp;
                
                cp = regcppush(0);      /* Save *all* the positions. */
-               REGCP_SET;
+               REGCP_SET(lastcp);
                regcp_set_to(PL_reg_call_cc->ss); /* Restore parens of
                                                    the caller. */
                PL_reginput = locinput; /* Make position available to
@@ -3078,7 +3221,7 @@ S_regmatch(pTHX_ regnode *prog)
                    regcpblow(cp);
                    sayYES;
                }
-               REGCP_UNWIND;
+               REGCP_UNWIND(lastcp);
                regcppop();
                PL_reg_call_cc = cur_call_cc;
                PL_regcc = cctmp;
@@ -3185,6 +3328,7 @@ S_regmatch(pTHX_ regnode *prog)
                          PTR2UV(scan), OP(scan));
            Perl_croak(aTHX_ "regexp memory corruption");
        }
+      reenter:
        scan = next;
     }
 
@@ -3210,6 +3354,11 @@ yes:
 #ifdef DEBUGGING
     PL_regindent--;
 #endif
+
+#if 0                                  /* Breaks $^R */
+    if (unwind)
+       regcpblow(firstcp);
+#endif
     return 1;
 
 no:
@@ -3221,6 +3370,55 @@ no:
     goto do_no;
 no_final:
 do_no:
+    if (unwind) {
+       re_unwind_t *uw = SSPTRt(unwind,re_unwind_t);
+
+       switch (uw->type) {
+       case RE_UNWIND_BRANCH:
+       case RE_UNWIND_BRANCHJ:
+       {
+           re_unwind_branch_t *uwb = &(uw->branch);
+           I32 lastparen = uwb->lastparen;
+           
+           REGCP_UNWIND(uwb->lastcp);
+           for (n = *PL_reglastparen; n > lastparen; n--)
+               PL_regendp[n] = -1;
+           *PL_reglastparen = n;
+           scan = next = uwb->next;
+           if ( !scan || 
+                OP(scan) != (uwb->type == RE_UNWIND_BRANCH 
+                             ? BRANCH : BRANCHJ) ) {           /* Failure */
+               unwind = uwb->prev;
+#ifdef DEBUGGING
+               PL_regindent--;
+#endif
+               goto do_no;
+           }
+           /* Have more choice yet.  Reuse the same uwb.  */
+           /*SUPPRESS 560*/
+           if ((n = (uwb->type == RE_UNWIND_BRANCH
+                     ? NEXT_OFF(next) : ARG(next))))
+               next += n;
+           else
+               next = NULL;    /* XXXX Needn't unwinding in this case... */
+           uwb->next = next;
+           next = NEXTOPER(scan);
+           if (uwb->type == RE_UNWIND_BRANCHJ)
+               next = NEXTOPER(next);
+           locinput = uwb->locinput;
+           nextchr = uwb->nextchr;
+#ifdef DEBUGGING
+           PL_regindent = uwb->regindent;
+#endif
+
+           goto reenter;
+       }
+       /* NOT REACHED */
+       default:
+           Perl_croak(aTHX_ "regexp unwind memory corruption");
+       }
+       /* NOT REACHED */
+    }
 #ifdef DEBUGGING
     PL_regindent--;
 #endif
@@ -3548,7 +3746,11 @@ S_reginclass(pTHX_ register regnode *p, register I32 c)
            (ANYOF_CLASS_TEST(p, ANYOF_UPPER)   &&  isUPPER_LC(c))  ||
            (ANYOF_CLASS_TEST(p, ANYOF_NUPPER)  && !isUPPER_LC(c))  ||
            (ANYOF_CLASS_TEST(p, ANYOF_XDIGIT)  &&  isXDIGIT(c))    ||
-           (ANYOF_CLASS_TEST(p, ANYOF_NXDIGIT) && !isXDIGIT(c))
+           (ANYOF_CLASS_TEST(p, ANYOF_NXDIGIT) && !isXDIGIT(c))    ||
+           (ANYOF_CLASS_TEST(p, ANYOF_PSXSPC)  &&  isPSXSPC(c))    ||
+           (ANYOF_CLASS_TEST(p, ANYOF_NPSXSPC) && !isPSXSPC(c))    ||
+           (ANYOF_CLASS_TEST(p, ANYOF_BLANK)   &&  isBLANK(c))    ||
+           (ANYOF_CLASS_TEST(p, ANYOF_NBLANK)  && !isBLANK(c))
            ) /* How's that for a conditional? */
        {
            match = TRUE;
@@ -3569,8 +3771,7 @@ S_reginclassutf8(pTHX_ regnode *f, U8 *p)
     if (swash_fetch(sv, p))
        match = TRUE;
     else if (flags & ANYOF_FOLD) {
-       I32 cf;
-       U8 tmpbuf[10];
+       U8 tmpbuf[UTF8_MAXLEN];
        if (flags & ANYOF_LOCALE) {
            PL_reg_flags |= RF_tainted;
            uv_to_utf8(tmpbuf, toLOWER_LC_utf8(p));
@@ -3655,4 +3856,3 @@ restore_pos(pTHXo_ void *arg)
        PL_curpm = PL_reg_oldcurpm;
     }  
 }
-