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Benchmark displays bogus CPU stats (suggested by Cedric Auzanne
[perl5.git] / regexec.c
index a61c88a..106c5d1 100644 (file)
--- a/regexec.c
+++ b/regexec.c
@@ -25,7 +25,7 @@
 #    define PERL_IN_XSUB_RE
 #  endif
 /* need access to debugger hooks */
-#  ifndef DEBUGGING
+#  if defined(PERL_EXT_RE_DEBUG) && !defined(DEBUGGING)
 #    define DEBUGGING
 #  endif
 #endif
 #  define Perl_regexec_flags my_regexec
 #  define Perl_regdump my_regdump
 #  define Perl_regprop my_regprop
+#  define Perl_re_intuit_start my_re_intuit_start
 /* *These* symbols are masked to allow static link. */
 #  define Perl_pregexec my_pregexec
 #  define Perl_reginitcolors my_reginitcolors 
+
+#  define PERL_NO_GET_CONTEXT
 #endif 
 
 /*SUPPRESS 112*/
  * regular-expression syntax might require a total rethink.
  */
 #include "EXTERN.h"
+#define PERL_IN_REGEXEC_C
 #include "perl.h"
 
+#ifdef PERL_IN_XSUB_RE
+#  if defined(PERL_CAPI) || defined(PERL_OBJECT)
+#    include "XSUB.h"
+#  endif
+#endif
+
 #include "regcomp.h"
 
 #define RF_tainted     1               /* tainted information used? */
 #define        STATIC  static
 #endif
 
-#ifndef PERL_OBJECT
-typedef I32 CHECKPOINT;
-
 /*
  * Forwards.
  */
 
-static I32 regmatch (regnode *prog);
-static I32 regrepeat (regnode *p, I32 max);
-static I32 regrepeat_hard (regnode *p, I32 max, I32 *lp);
-static I32 regtry (regexp *prog, char *startpos);
-
-static bool reginclass (char *p, I32 c);
-static bool reginclassutf8 (regnode *f, U8* p);
-static CHECKPOINT regcppush (I32 parenfloor);
-static char * regcppop (void);
-static char * regcp_set_to (I32 ss);
-static void cache_re (regexp *prog);
-static void restore_pos (void *arg);
-#endif
-
-#define REGINCLASS(p,c)  (*(p) ? reginclass(p,c) : ANYOF_TEST(p,c))
+#define REGINCLASS(p,c)  (ANYOF_FLAGS(p) ? reginclass(p,c) : ANYOF_BITMAP_TEST(p,c))
 #define REGINCLASSUTF8(f,p)  (ARG1(f) ? reginclassutf8(f,p) : swash_fetch((SV*)PL_regdata->data[ARG2(f)],p))
 
 #define CHR_SVLEN(sv) (UTF ? sv_len_utf8(sv) : SvCUR(sv))
 #define CHR_DIST(a,b) (UTF ? utf8_distance(a,b) : a - b)
 
-#ifndef PERL_OBJECT
-static U8 * reghop (U8 *pos, I32 off);
-static U8 * reghopmaybe (U8 *pos, I32 off);
-#endif
 #define reghop_c(pos,off) ((char*)reghop((U8*)pos, off))
 #define reghopmaybe_c(pos,off) ((char*)reghopmaybe((U8*)pos, off))
 #define HOP(pos,off) (UTF ? reghop((U8*)pos, off) : (U8*)(pos + off))
@@ -129,8 +118,11 @@ static U8 * reghopmaybe (U8 *pos, I32 off);
 #define HOPc(pos,off) ((char*)HOP(pos,off))
 #define HOPMAYBEc(pos,off) ((char*)HOPMAYBE(pos,off))
 
+static void restore_pos(pTHXo_ void *arg);
+
+
 STATIC CHECKPOINT
-regcppush(I32 parenfloor)
+S_regcppush(pTHX_ I32 parenfloor)
 {
     dTHR;
     int retval = PL_savestack_ix;
@@ -154,16 +146,16 @@ regcppush(I32 parenfloor)
 
 /* These are needed since we do not localize EVAL nodes: */
 #  define REGCP_SET  DEBUG_r(PerlIO_printf(Perl_debug_log,             \
-                            "  Setting an EVAL scope, savestack=%i\n", \
-                            PL_savestack_ix)); lastcp = PL_savestack_ix
+                            "  Setting an EVAL scope, savestack=%"IVdf"\n",    \
+                            (IV)PL_savestack_ix)); lastcp = PL_savestack_ix
 
 #  define REGCP_UNWIND  DEBUG_r(lastcp != PL_savestack_ix ?            \
                                PerlIO_printf(Perl_debug_log,           \
-                               "  Clearing an EVAL scope, savestack=%i..%i\n", \
-                               lastcp, PL_savestack_ix) : 0); regcpblow(lastcp)
+                               "  Clearing an EVAL scope, savestack=%"IVdf"..%"IVdf"\n", \
+                               (IV)lastcp, (IV)PL_savestack_ix) : 0); regcpblow(lastcp)
 
 STATIC char *
-regcppop(void)
+S_regcppop(pTHX)
 {
     dTHR;
     I32 i = SSPOPINT;
@@ -184,18 +176,18 @@ regcppop(void)
            PL_regendp[paren] = tmps;
        DEBUG_r(
            PerlIO_printf(Perl_debug_log,
-                         "     restoring \\%d to %d(%d)..%d%s\n",
-                         paren, PL_regstartp[paren], 
-                         PL_reg_start_tmp[paren] - PL_bostr,
-                         PL_regendp[paren], 
+                         "     restoring \\%"UVuf" to %"IVdf"(%"IVdf")..%"IVdf"%s\n",
+                         (UV)paren, (IV)PL_regstartp[paren], 
+                         (IV)(PL_reg_start_tmp[paren] - PL_bostr),
+                         (IV)PL_regendp[paren], 
                          (paren > *PL_reglastparen ? "(no)" : ""));
        );
     }
     DEBUG_r(
        if (*PL_reglastparen + 1 <= PL_regnpar) {
            PerlIO_printf(Perl_debug_log,
-                         "     restoring \\%d..\\%d to undef\n",
-                         *PL_reglastparen + 1, PL_regnpar);
+                         "     restoring \\%"IVdf"..\\%"IVdf" to undef\n",
+                         (IV)(*PL_reglastparen + 1), (IV)PL_regnpar);
        }
     );
     for (paren = *PL_reglastparen + 1; paren <= PL_regnpar; paren++) {
@@ -207,7 +199,7 @@ regcppop(void)
 }
 
 STATIC char *
-regcp_set_to(I32 ss)
+S_regcp_set_to(pTHX_ I32 ss)
 {
     dTHR;
     I32 tmp = PL_savestack_ix;
@@ -237,7 +229,7 @@ typedef struct re_cc_state
  - pregexec - match a regexp against a string
  */
 I32
-pregexec(register regexp *prog, char *stringarg, register char *strend,
+Perl_pregexec(pTHX_ register regexp *prog, char *stringarg, register char *strend,
         char *strbeg, I32 minend, SV *screamer, U32 nosave)
 /* strend: pointer to null at end of string */
 /* strbeg: real beginning of string */
@@ -250,7 +242,7 @@ pregexec(register regexp *prog, char *stringarg, register char *strend,
 }
 
 STATIC void
-cache_re(regexp *prog)
+S_cache_re(pTHX_ regexp *prog)
 {
     dTHR;
     PL_regprecomp = prog->precomp;             /* Needed for FAIL. */
@@ -262,311 +254,545 @@ cache_re(regexp *prog)
     PL_reg_re = prog;    
 }
 
-STATIC void
-restore_pos(void *arg)
-{
-    dTHR;
-    if (PL_reg_eval_set) {
-       if (PL_reg_oldsaved) {
-           PL_reg_re->subbeg = PL_reg_oldsaved;
-           PL_reg_re->sublen = PL_reg_oldsavedlen;
-           RX_MATCH_COPIED_on(PL_reg_re);
-       }
-       PL_reg_magic->mg_len = PL_reg_oldpos;
-       PL_reg_eval_set = 0;
-       PL_curpm = PL_reg_oldcurpm;
-    }  
-}
-
-
-/*
- - regexec_flags - match a regexp against a string
+/* 
+ * Need to implement the following flags for reg_anch:
+ *
+ * USE_INTUIT_NOML             - Useful to call re_intuit_start() first
+ * USE_INTUIT_ML
+ * INTUIT_AUTORITATIVE_NOML    - Can trust a positive answer
+ * INTUIT_AUTORITATIVE_ML
+ * INTUIT_ONCE_NOML            - Intuit can match in one location only.
+ * INTUIT_ONCE_ML
+ *
+ * Another flag for this function: SECOND_TIME (so that float substrs
+ * with giant delta may be not rechecked).
  */
-I32
-regexec_flags(register regexp *prog, char *stringarg, register char *strend,
-             char *strbeg, I32 minend, SV *sv, void *data, U32 flags)
-/* strend: pointer to null at end of string */
-/* strbeg: real beginning of string */
-/* minend: end of match must be >=minend after stringarg. */
-/* data: May be used for some additional optimizations. */
-/* nosave: For optimizations. */
-{
-    dTHR;
-    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 */
-    CURCUR cc;
-    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. */
-    char *scream_olds;
-    SV* oreplsv = GvSV(PL_replgv);
-
-    cc.cur = 0;
-    cc.oldcc = 0;
-    PL_regcc = &cc;
-
-    cache_re(prog);
-#ifdef DEBUGGING
-    PL_regnarrate = PL_debug & 512;
-#endif
-
-    /* Be paranoid... */
-    if (prog == NULL || startpos == NULL) {
-       croak("NULL regexp parameter");
-       return 0;
-    }
 
-    minlen = prog->minlen;
-    if (strend - startpos < minlen) goto phooey;
+/* Assumptions: if ANCH_GPOS, then strpos is anchored. XXXX Check GPOS logic */
 
-    if (startpos == strbeg)    /* is ^ valid at stringarg? */
-       PL_regprev = '\n';
-    else {
-       PL_regprev = (U32)stringarg[-1];
-       if (!PL_multiline && PL_regprev == '\n')
-           PL_regprev = '\0';          /* force ^ to NOT match */
-    }
+/* If SCREAM, then SvPVX(sv) should be compatible with strpos and strend.
+   Otherwise, only SvCUR(sv) is used to get strbeg. */
 
-    /* Check validity of program. */
-    if (UCHARAT(prog->program) != REG_MAGIC) {
-       croak("corrupted regexp program");
-    }
+/* XXXX We assume that strpos is strbeg unless sv. */
 
-    PL_reg_flags = 0;
-    PL_reg_eval_set = 0;
+/* XXXX Some places assume that there is a fixed substring.
+       An update may be needed if optimizer marks as "INTUITable"
+       RExen without fixed substrings.  Similarly, it is assumed that
+       lengths of all the strings are no more than minlen, thus they
+       cannot come from lookahead.
+       (Or minlen should take into account lookahead.) */
 
-    if (prog->reganch & ROPT_UTF8)
-       PL_reg_flags |= RF_utf8;
-
-    /* Mark beginning of line for ^ and lookbehind. */
-    PL_regbol = startpos;
-    PL_bostr  = strbeg;
-    PL_reg_sv = sv;
+/* A failure to find a constant substring means that there is no need to make
+   an expensive call to REx engine, thus we celebrate a failure.  Similarly,
+   finding a substring too deep into the string means that less calls to
+   regtry() should be needed.
 
-    /* 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;
+   REx compiler's optimizer found 4 possible hints:
+       a) Anchored substring;
+       b) Fixed substring;
+       c) Whether we are anchored (beginning-of-line or \G);
+       d) First node (of those at offset 0) which may distingush positions;
+   We use a)b)d) and multiline-part of c), and try to find a position in the
+   string which does not contradict any of them.
+ */
 
-    /* We start without call_cc context.  */
-    PL_reg_call_cc = 0;
+/* Most of decisions we do here should have been done at compile time.
+   The nodes of the REx which we used for the search should have been
+   deleted from the finite automaton. */
 
-    /* If there is a "must appear" string, look for it. */
-    s = startpos;
-    if (!(flags & REXEC_CHECKED) 
-       && prog->check_substr != Nullsv &&
-       !(prog->reganch & ROPT_ANCH_GPOS) &&
-       (!(prog->reganch & (ROPT_ANCH_BOL | ROPT_ANCH_MBOL))
-        || (PL_multiline && prog->check_substr == prog->anchored_substr)) )
-    {
-       char *t;
-       start_shift = prog->check_offset_min;   /* okay to underestimate on CC */
-       /* Should be nonnegative! */
-       end_shift = minlen - start_shift -
-           CHR_SVLEN(prog->check_substr) + (SvTAIL(prog->check_substr) != 0);
-       if (flags & REXEC_SCREAM) {
-           SV *c = prog->check_substr;
-
-           if (PL_screamfirst[BmRARE(c)] >= 0
-               || ( BmRARE(c) == '\n'
-                    && (BmPREVIOUS(c) == SvCUR(c) - 1)
-                    && SvTAIL(c) ))
-                   s = screaminstr(sv, prog->check_substr, 
-                                   start_shift + (stringarg - strbeg),
-                                   end_shift, &scream_pos, 0);
-           else
-                   s = Nullch;
-           scream_olds = s;
-       }
-       else
-           s = fbm_instr((unsigned char*)s + start_shift,
-                         (unsigned char*)strend - end_shift,
-               prog->check_substr, PL_multiline ? FBMrf_MULTILINE : 0);
-       if (!s) {
-           ++BmUSEFUL(prog->check_substr);     /* hooray */
-           goto phooey;        /* not present */
-       }
-       else if (s - stringarg > prog->check_offset_max &&
-                (UTF 
-                   ? ((t = reghopmaybe_c(s, -(prog->check_offset_max))) && t >= stringarg)
-                   : (t = s - prog->check_offset_max) != 0
-                )
-               )
-       {
-           ++BmUSEFUL(prog->check_substr);     /* hooray/2 */
-           s = t;
-       }
-       else if (!(prog->reganch & ROPT_NAUGHTY)
-                  && --BmUSEFUL(prog->check_substr) < 0
-                  && prog->check_substr == prog->float_substr) { /* boo */
-           SvREFCNT_dec(prog->check_substr);
-           prog->check_substr = Nullsv;        /* disable */
-           prog->float_substr = Nullsv;        /* clear */
-           s = startpos;
-       }
-       else
-           s = startpos;
-    }
+char *
+Perl_re_intuit_start(pTHX_ regexp *prog, SV *sv, char *strpos,
+                    char *strend, U32 flags, re_scream_pos_data *data)
+{
+    register I32 start_shift;
+    /* Should be nonnegative! */
+    register I32 end_shift;
+    register char *s;
+    register SV *check;
+    char *t;
+    I32 ml_anch;
+    char *tmp;
+    register char *other_last = Nullch;        /* other substr checked before this */
+    char *check_at;                    /* check substr found at this pos */
+#ifdef DEBUGGING
+    char *i_strpos = strpos;
+#endif
 
-    DEBUG_r(if (!PL_colorset) reginitcolors());
-    DEBUG_r(PerlIO_printf(Perl_debug_log, 
-                     "%sMatching%s `%s%.60s%s%s' against `%s%.*s%s%s'\n",
+    DEBUG_r( if (!PL_colorset) reginitcolors() );
+    DEBUG_r(PerlIO_printf(Perl_debug_log,
+                     "%sGuessing start of match, REx%s `%s%.60s%s%s' against `%s%.*s%s%s'...\n",
                      PL_colors[4],PL_colors[5],PL_colors[0],
                      prog->precomp,
                      PL_colors[1],
                      (strlen(prog->precomp) > 60 ? "..." : ""),
-                     PL_colors[0], 
-                     (strend - startpos > 60 ? 60 : strend - startpos),
-                     startpos, PL_colors[1],
-                     (strend - startpos > 60 ? "..." : ""))
+                     PL_colors[0],
+                     (int)(strend - strpos > 60 ? 60 : strend - strpos),
+                     strpos, PL_colors[1],
+                     (strend - strpos > 60 ? "..." : ""))
        );
 
-    if (prog->reganch & ROPT_GPOS_SEEN) {
-       MAGIC *mg;
-
-       if (!(flags & REXEC_IGNOREPOS) && sv && SvTYPE(sv) >= SVt_PVMG
-           && SvMAGIC(sv) && (mg = mg_find(sv, 'g')) && mg->mg_len >= 0)
-           PL_reg_ganch = strbeg + mg->mg_len;
-       else
-           PL_reg_ganch = startpos;
+    if (prog->minlen > strend - strpos) {
+       DEBUG_r(PerlIO_printf(Perl_debug_log, "String too short...\n"));
+       goto fail;
     }
-
-    /* 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 (regtry(prog, startpos))
-           goto got_it;
-       else if (PL_multiline || (prog->reganch & ROPT_IMPLICIT)
-                || (prog->reganch & ROPT_ANCH_MBOL)) /* XXXX SBOL? */
-       {
-           if (minlen)
-               dontbother = minlen - 1;
-           strend = HOPc(strend, -dontbother);
-           /* for multiline we only have to try after newlines */
-           if (s > startpos)
-               s--;
-           while (s < strend) {
-               if (*s++ == '\n') {     /* don't need PL_utf8skip here */
-                   if (s < strend && regtry(prog, s))
-                       goto got_it;
+    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) {
+           /* 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(check)) {
+               slen = SvCUR(check);    /* >= 1 */
+
+               if ( strend - s > slen || strend - s < slen - 1 
+                    || (strend - s == slen && strend[-1] != '\n')) {
+                   DEBUG_r(PerlIO_printf(Perl_debug_log, "String too long...\n"));
+                   goto fail_finish;
+               }
+               /* Now should match s[0..slen-2] */
+               slen--;
+               if (slen && (*SvPVX(check) != *s
+                            || (slen > 1
+                                && memNE(SvPVX(check), s, slen)))) {
+                 report_neq:
+                   DEBUG_r(PerlIO_printf(Perl_debug_log, "String not equal...\n"));
+                   goto fail_finish;
                }
            }
+           else if (*SvPVX(check) != *s
+                    || ((slen = SvCUR(check)) > 1
+                        && memNE(SvPVX(check), s, slen)))
+               goto report_neq;
+           goto success_at_start;
        }
-       goto phooey;
-    } else if (prog->reganch & ROPT_ANCH_GPOS) {
-       if (regtry(prog, PL_reg_ganch))
-           goto got_it;
-       goto phooey;
+       /* Match is anchored, but substr is not anchored wrt beg-of-str. */
+       s = strpos;
+       start_shift = prog->check_offset_min; /* okay to underestimate on CC */
+       end_shift = prog->minlen - start_shift -
+           CHR_SVLEN(check) + (SvTAIL(check) != 0);
+       if (!ml_anch) {
+           I32 end = prog->check_offset_max + CHR_SVLEN(check)
+                                        - (SvTAIL(check) != 0);
+           I32 eshift = strend - s - end;
+
+           if (end_shift < eshift)
+               end_shift = eshift;
+       }
+    }
+    else {                             /* Can match at random position */
+       ml_anch = 0;
+       s = strpos;
+       start_shift = prog->check_offset_min; /* okay to underestimate on CC */
+       /* Should be nonnegative! */
+       end_shift = prog->minlen - start_shift -
+           CHR_SVLEN(check) + (SvTAIL(check) != 0);
     }
 
-    /* Messy cases:  unanchored match. */
-    if (prog->anchored_substr && prog->reganch & ROPT_SKIP) { 
-       /* we have /x+whatever/ */
-       /* it must be a one character string */
-       char ch = SvPVX(prog->anchored_substr)[0];
-       if (UTF) {
-           while (s < strend) {
-               if (*s == ch) {
-                   if (regtry(prog, s)) goto got_it;
-                   s += UTF8SKIP(s);
-                   while (s < strend && *s == ch)
-                       s += UTF8SKIP(s);
+#ifdef DEBUGGING       /* 7/99: reports of failure (with the older version) */
+    if (end_shift < 0)
+       Perl_croak(aTHX_ "panic: end_shift");
+#endif
+
+  restart:
+    /* Find a possible match in the region s..strend by looking for
+       the "check" substring in the region corrected by start/end_shift. */
+    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;
+
+       if (PL_screamfirst[BmRARE(check)] >= 0
+           || ( BmRARE(check) == '\n'
+                && (BmPREVIOUS(check) == SvCUR(check) - 1)
+                && SvTAIL(check) ))
+           s = screaminstr(sv, check, 
+                           start_shift + (s - strbeg), end_shift, pp, 0);
+       else
+           goto fail_finish;
+       if (data)
+           *data->scream_olds = s;
+    }
+    else
+       s = fbm_instr((unsigned char*)s + start_shift,
+                     (unsigned char*)strend - end_shift,
+                     check, PL_multiline ? FBMrf_MULTILINE : 0);
+
+    /* Update the count-of-usability, remove useless subpatterns,
+       unshift s.  */
+
+    DEBUG_r(PerlIO_printf(Perl_debug_log, "%s %s substr `%s%.*s%s'%s%s",
+                         (s ? "Found" : "Did not find"),
+                         ((check == prog->anchored_substr) ? "anchored" : "floating"),
+                         PL_colors[0],
+                         (int)(SvCUR(check) - (SvTAIL(check)!=0)),
+                         SvPVX(check),
+                         PL_colors[1], (SvTAIL(check) ? "$" : ""),
+                         (s ? " at offset " : "...\n") ) );
+
+    if (!s)
+       goto fail_finish;
+
+    check_at = s;
+
+    /* Finish the diagnostic message */
+    DEBUG_r(PerlIO_printf(Perl_debug_log, "%ld...\n", (long)(s - i_strpos)) );
+
+    /* Got a candidate.  Check MBOL anchoring, and the *other* substr.
+       Start with the other substr.
+       XXXX no SCREAM optimization yet - and a very coarse implementation
+       XXXX /ttx+/ results in anchored=`ttx', floating=`x'.  floating will
+               *always* match.  Probably should be marked during compile...
+       Probably it is right to do no SCREAM here...
+     */
+
+    if (prog->float_substr && prog->anchored_substr) {
+       /* Take into account the "other" substring. */
+       /* XXXX May be hopelessly wrong for UTF... */
+       if (!other_last)
+           other_last = strpos;
+       if (check == prog->float_substr) {
+         do_other_anchored:
+           {
+               char *last = s - start_shift, *last1, *last2;
+               char *s1 = s;
+
+               tmp = PL_bostr;
+               t = s - prog->check_offset_max;
+               if (s - strpos > prog->check_offset_max  /* signed-corrected t > strpos */
+                   && (!(prog->reganch & ROPT_UTF8)
+                       || (PL_bostr = strpos, /* Used in regcopmaybe() */
+                           (t = reghopmaybe_c(s, -(prog->check_offset_max)))
+                           && t > strpos)))
+                   /* EMPTY */;
+               else
+                   t = strpos;
+               t += prog->anchored_offset;
+               if (t < other_last)     /* These positions already checked */
+                   t = other_last;
+               PL_bostr = tmp;
+               last2 = last1 = strend - prog->minlen;
+               if (last < last1)
+                   last1 = last;
+ /* XXXX It is not documented what units *_offsets are in.  Assume bytes.  */
+               /* On end-of-str: see comment below. */
+               s = fbm_instr((unsigned char*)t,
+                             (unsigned char*)last1 + prog->anchored_offset
+                                + SvCUR(prog->anchored_substr)
+                                - (SvTAIL(prog->anchored_substr)!=0),
+                             prog->anchored_substr, PL_multiline ? FBMrf_MULTILINE : 0);
+               DEBUG_r(PerlIO_printf(Perl_debug_log, "%s anchored substr `%s%.*s%s'%s",
+                       (s ? "Found" : "Contradicts"),
+                       PL_colors[0],
+                         (int)(SvCUR(prog->anchored_substr)
+                         - (SvTAIL(prog->anchored_substr)!=0)),
+                         SvPVX(prog->anchored_substr),
+                         PL_colors[1], (SvTAIL(prog->anchored_substr) ? "$" : "")));
+               if (!s) {
+                   if (last1 >= last2) {
+                       DEBUG_r(PerlIO_printf(Perl_debug_log,
+                                               ", giving up...\n"));
+                       goto fail_finish;
+                   }
+                   DEBUG_r(PerlIO_printf(Perl_debug_log,
+                       ", trying floating at offset %ld...\n",
+                       (long)(s1 + 1 - i_strpos)));
+                   PL_regeol = strend;                 /* Used in HOP() */
+                   other_last = last1 + prog->anchored_offset + 1;
+                   s = HOPc(last, 1);
+                   goto restart;
+               }
+               else {
+                   DEBUG_r(PerlIO_printf(Perl_debug_log, " at offset %ld...\n",
+                         (long)(s - i_strpos)));
+                   t = s - prog->anchored_offset;
+                   other_last = s + 1;
+                   s = s1;
+                   if (t == strpos)
+                       goto try_at_start;
+                   goto try_at_offset;
                }
-               s += UTF8SKIP(s);
            }
        }
-       else {
-           while (s < strend) {
-               if (*s == ch) {
-                   if (regtry(prog, s)) goto got_it;
-                   s++;
-                   while (s < strend && *s == ch)
-                       s++;
+       else {          /* Take into account the floating substring. */
+               char *last, *last1;
+               char *s1 = s;
+
+               t = s - start_shift;
+               last1 = last = strend - prog->minlen + prog->float_min_offset;
+               if (last - t > prog->float_max_offset)
+                   last = t + prog->float_max_offset;
+               s = t + prog->float_min_offset;
+               if (s < other_last)
+                   s = other_last;
+ /* XXXX It is not documented what units *_offsets are in.  Assume bytes.  */
+               /* fbm_instr() takes into account exact value of end-of-str
+                  if the check is SvTAIL(ed).  Since false positives are OK,
+                  and end-of-str is not later than strend we are OK. */
+               s = fbm_instr((unsigned char*)s,
+                             (unsigned char*)last + SvCUR(prog->float_substr)
+                                 - (SvTAIL(prog->float_substr)!=0),
+                             prog->float_substr, PL_multiline ? FBMrf_MULTILINE : 0);
+               DEBUG_r(PerlIO_printf(Perl_debug_log, "%s floating substr `%s%.*s%s'%s",
+                       (s ? "Found" : "Contradicts"),
+                       PL_colors[0],
+                         (int)(SvCUR(prog->float_substr)
+                         - (SvTAIL(prog->float_substr)!=0)),
+                         SvPVX(prog->float_substr),
+                         PL_colors[1], (SvTAIL(prog->float_substr) ? "$" : "")));
+               if (!s) {
+                   if (last1 == last) {
+                       DEBUG_r(PerlIO_printf(Perl_debug_log,
+                                               ", giving up...\n"));
+                       goto fail_finish;
+                   }
+                   DEBUG_r(PerlIO_printf(Perl_debug_log,
+                       ", trying anchored starting at offset %ld...\n",
+                       (long)(s1 + 1 - i_strpos)));
+                   other_last = last + 1;
+                   PL_regeol = strend;                 /* Used in HOP() */
+                   s = HOPc(t, 1);
+                   goto restart;
+               }
+               else {
+                   DEBUG_r(PerlIO_printf(Perl_debug_log, " at offset %ld...\n",
+                         (long)(s - i_strpos)));
+                   other_last = s + 1;
+                   s = s1;
+                   if (t == strpos)
+                       goto try_at_start;
+                   goto try_at_offset;
                }
-               s++;
-           }
        }
     }
-    /*SUPPRESS 560*/
-    else if (prog->anchored_substr != Nullsv
-            || (prog->float_substr != Nullsv 
-                && prog->float_max_offset < strend - s)) {
-       SV *must = prog->anchored_substr 
-           ? prog->anchored_substr : prog->float_substr;
-       I32 back_max = 
-           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 */
-                         -(CHR_SVLEN(must) - (SvTAIL(must) != 0) + back_min));
-       char *last1;            /* Last position checked before */
-
-       if (s > PL_bostr)
-           last1 = HOPc(s, -1);
-       else
-           last1 = s - 1;      /* bogus */
 
-       /* XXXX check_substr already used to find `s', can optimize if
-          check_substr==must. */
-       scream_pos = -1;
-       dontbother = end_shift;
-       strend = HOPc(strend, -dontbother);
-       while ( (s <= last) &&
-               ((flags & REXEC_SCREAM) 
-                ? (s = screaminstr(sv, must, HOPc(s, back_min) - strbeg,
-                                   end_shift, &scream_pos, 0))
-                : (s = fbm_instr((unsigned char*)HOP(s, back_min),
-                                 (unsigned char*)strend, must, 
-                                 PL_multiline ? FBMrf_MULTILINE : 0))) ) {
-           if (HOPc(s, -back_max) > last1) {
-               last1 = HOPc(s, -back_min);
-               s = HOPc(s, -back_max);
-           }
-           else {
-               char *t = (last1 >= PL_bostr) ? HOPc(last1, 1) : last1 + 1;
-
-               last1 = HOPc(s, -back_min);
-               s = t;          
-           }
-           if (UTF) {
-               while (s <= last1) {
-                   if (regtry(prog, s))
-                       goto got_it;
-                   s += UTF8SKIP(s);
+    t = s - prog->check_offset_max;
+    tmp = PL_bostr;
+    if (s - strpos > prog->check_offset_max  /* signed-corrected t > strpos */
+        && (!(prog->reganch & ROPT_UTF8)
+           || (PL_bostr = strpos, /* Used in regcopmaybe() */
+               ((t = reghopmaybe_c(s, -(prog->check_offset_max)))
+                && t > strpos)))) {
+       PL_bostr = tmp;
+       /* Fixed substring is found far enough so that the match
+          cannot start at strpos. */
+      try_at_offset:
+       if (ml_anch && t[-1] != '\n') {
+           /* Eventually fbm_*() should handle this, but often
+              anchored_offset is not 0, so this check will not be wasted. */
+           /* XXXX In the code below we prefer to look for "^" even in
+              presence of anchored substrings.  And we search even
+              beyond the found float position.  These pessimizations
+              are historical artefacts only.  */
+         find_anchor:
+           while (t < strend - prog->minlen) {
+               if (*t == '\n') {
+                   if (t < s - prog->check_offset_min) {
+                       if (prog->anchored_substr) {
+                           /* We definitely contradict the found anchored
+                              substr.  Due to the above check we do not
+                              contradict "check" substr.
+                              Thus we can arrive here only if check substr
+                              is float.  Redo checking for "other"=="fixed".
+                            */
+                           strpos = t + 1;                         
+                           DEBUG_r(PerlIO_printf(Perl_debug_log, "Found /%s^%s/m at offset %ld, rescanning for anchored from offset %ld...\n",
+                               PL_colors[0],PL_colors[1], (long)(strpos - i_strpos), (long)(strpos - i_strpos + prog->anchored_offset)));
+                           goto do_other_anchored;
+                       }
+                       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",
+                       PL_colors[0],PL_colors[1], (long)(t + 1 - i_strpos)));
+                   strpos = s = t + 1;
+                   goto restart;
                }
+               t++;
            }
-           else {
-               while (s <= last1) {
-                   if (regtry(prog, s))
-                       goto got_it;
-                   s++;
+           DEBUG_r(PerlIO_printf(Perl_debug_log, "Did not find /%s^%s/m...\n",
+                       PL_colors[0],PL_colors[1]));
+           goto fail_finish;
+       }
+       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
+          - no optimization of calling REx engine can be performed,
+          unless it was an MBOL and we are not after MBOL. */
+      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'
+           /* 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]);
+       );
+      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)
+       {
+           /* If flags & SOMETHING - do not do it many times on the same match */
+           SvREFCNT_dec(prog->check_substr);
+           prog->check_substr = Nullsv;        /* disable */
+           prog->float_substr = Nullsv;        /* clear */
+           s = strpos;
+           /* XXXX This is a remnant of the old implementation.  It
+                   looks wasteful, since now INTUIT can use many
+                   other heuristics. */
+           prog->reganch &= ~RE_USE_INTUIT;
+       }
+       else
+           s = strpos;
+    }
+
+    /* Last resort... */
+    /* XXXX BmUSEFUL already changed, maybe multiple change is meaningful... */
+    if (prog->regstclass) {
+       /* minlen == 0 is possible if regstclass is \b or \B,
+          and the fixed substr is ''$.
+          Since minlen is already taken into account, s+1 is before strend;
+          accidentally, minlen >= 1 guaranties no false positives at s + 1
+          even for \b or \B.  But (minlen? 1 : 0) below assumes that
+          regstclass does not come from lookahead...  */
+       /* If regstclass takes bytelength more than 1: If charlength==1, OK.
+          This leaves EXACTF 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? cl_l : 0)
+               : (prog->float_substr ? check_at - start_shift + cl_l
+                                     : strend) ;
+       char *startpos = sv ? strend - SvCUR(sv) : s;
+
+       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
+           char *what;
+#endif
+           if (endpos == strend) {
+               DEBUG_r( PerlIO_printf(Perl_debug_log,
+                               "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) {
+               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;
+                   }
+                   DEBUG_r( PerlIO_printf(Perl_debug_log,
+                               "Trying %s substr starting at offset %ld...\n",
+                                what, (long)(s + start_shift - i_strpos)) );
+                   goto restart;
                }
-           }
+               /* Have both, check_string is floating */
+               if (t + start_shift >= check_at) /* Contradicts floating=check */
+                   goto retry_floating_check;
+               /* Recheck anchored substring, but not floating... */
+               s = check_at; 
+               DEBUG_r( PerlIO_printf(Perl_debug_log,
+                         "Trying 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;
+               DEBUG_r( PerlIO_printf(Perl_debug_log,
+                         "Trying /^/m starting at offset %ld...\n",
+                         (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;
+           DEBUG_r( what = "floating" );
+           goto hop_and_restart;
        }
-       goto phooey;
+       DEBUG_r( if (t != s)
+                    PerlIO_printf(Perl_debug_log, 
+                       "By STCLASS: moving %ld --> %ld\n",
+                       (long)(t - i_strpos), (long)(s - i_strpos));
+                else
+                    PerlIO_printf(Perl_debug_log, 
+                       "Does not contradict STCLASS...\n") );
     }
-    else if (c = prog->regstclass) {
+    DEBUG_r(PerlIO_printf(Perl_debug_log, "%sGuessed:%s match at offset %ld\n",
+                         PL_colors[4], PL_colors[5], (long)(s - i_strpos)) );
+    return s;
+
+  fail_finish:                         /* Substring not found */
+    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]));
+    return Nullch;
+}
+
+/* We know what class REx starts with.  Try to find this position... */
+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 *cc;
+       char *m;
+       int ln;
+       int c1;
+       int c2;
+       char *e;
+       register I32 tmp = 1;   /* Scratch variable? */
 
-       if (minlen)
-           dontbother = minlen - 1;
-       strend = HOPc(strend, -dontbother);     /* don't bother with what can't match */
-       tmp = 1;
        /* We know what class it must start with. */
        switch (OP(c)) {
        case ANYOFUTF8:
-           cc = (char *) OPERAND(c);
            while (s < strend) {
                if (REGINCLASSUTF8(c, (U8*)s)) {
-                   if (tmp && regtry(prog, s))
+                   if (tmp && (norun || regtry(prog, s)))
                        goto got_it;
                    else
                        tmp = doevery;
@@ -577,10 +803,9 @@ regexec_flags(register regexp *prog, char *stringarg, register char *strend,
            }
            break;
        case ANYOF:
-           cc = (char *) OPERAND(c);
            while (s < strend) {
-               if (REGINCLASS(cc, *s)) {
-                   if (tmp && regtry(prog, s))
+               if (REGINCLASS(c, *s)) {
+                   if (tmp && (norun || regtry(prog, s)))
                        goto got_it;
                    else
                        tmp = doevery;
@@ -590,97 +815,120 @@ regexec_flags(register regexp *prog, char *stringarg, register char *strend,
                s++;
            }
            break;
+       case EXACTF:
+           m = STRING(c);
+           ln = STR_LEN(c);
+           c1 = *m;
+           c2 = PL_fold[c1];
+           goto do_exactf;
+       case EXACTFL:
+           m = STRING(c);
+           ln = STR_LEN(c);
+           c1 = *m;
+           c2 = PL_fold_locale[c1];
+         do_exactf:
+           e = strend - ln;
+
+           if (norun && e < s)
+               e = s;                  /* Due to minlen logic of intuit() */
+           /* 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)))
+                        && (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)))
+                        && (norun || regtry(prog, s)) )
+                       goto got_it;
+                   s++;
+               }
+           }
+           break;
        case BOUNDL:
            PL_reg_flags |= RF_tainted;
            /* FALL THROUGH */
        case BOUND:
-           if (minlen) {
-               dontbother++;
-               strend -= 1;
-           }
-           tmp = (s != startpos) ? UCHARAT(s - 1) : PL_regprev;
+           tmp = (s != startpos) ? UCHARAT(s - 1) : '\n';
            tmp = ((OP(c) == BOUND ? isALNUM(tmp) : isALNUM_LC(tmp)) != 0);
            while (s < strend) {
                if (tmp == !(OP(c) == BOUND ? isALNUM(*s) : isALNUM_LC(*s))) {
                    tmp = !tmp;
-                   if (regtry(prog, s))
+                   if ((norun || regtry(prog, s)))
                        goto got_it;
                }
                s++;
            }
-           if ((minlen || tmp) && regtry(prog,s))
+           if ((!prog->minlen && tmp) && (norun || regtry(prog, s)))
                goto got_it;
            break;
        case BOUNDLUTF8:
            PL_reg_flags |= RF_tainted;
            /* FALL THROUGH */
        case BOUNDUTF8:
-           if (minlen) {
-               dontbother++;
-               strend = reghop_c(strend, -1);
-           }
-           tmp = (I32)(s != startpos) ? utf8_to_uv(reghop((U8*)s, -1), 0) : PL_regprev;
-           tmp = ((OP(c) == BOUND ? isALNUM_uni(tmp) : isALNUM_LC_uni(tmp)) != 0);
+           tmp = (I32)(s != startpos) ? utf8_to_uv(reghop((U8*)s, -1), 0) : '\n';
+           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)))
                {
                    tmp = !tmp;
-                   if (regtry(prog, s))
+                   if ((norun || regtry(prog, s)))
                        goto got_it;
                }
                s += UTF8SKIP(s);
            }
-           if ((minlen || tmp) && regtry(prog,s))
+           if ((!prog->minlen && tmp) && (norun || regtry(prog, s)))
                goto got_it;
            break;
        case NBOUNDL:
            PL_reg_flags |= RF_tainted;
            /* FALL THROUGH */
        case NBOUND:
-           if (minlen) {
-               dontbother++;
-               strend -= 1;
-           }
-           tmp = (s != startpos) ? UCHARAT(s - 1) : PL_regprev;
+           tmp = (s != startpos) ? UCHARAT(s - 1) : '\n';
            tmp = ((OP(c) == NBOUND ? isALNUM(tmp) : isALNUM_LC(tmp)) != 0);
            while (s < strend) {
                if (tmp == !(OP(c) == NBOUND ? isALNUM(*s) : isALNUM_LC(*s)))
                    tmp = !tmp;
-               else if (regtry(prog, s))
+               else if ((norun || regtry(prog, s)))
                    goto got_it;
                s++;
            }
-           if ((minlen || !tmp) && regtry(prog,s))
+           if ((!prog->minlen && !tmp) && (norun || regtry(prog, s)))
                goto got_it;
            break;
        case NBOUNDLUTF8:
            PL_reg_flags |= RF_tainted;
            /* FALL THROUGH */
        case NBOUNDUTF8:
-           if (minlen) {
-               dontbother++;
-               strend = reghop_c(strend, -1);
-           }
-           tmp = (I32)(s != startpos) ? utf8_to_uv(reghop((U8*)s, -1), 0) : PL_regprev;
-           tmp = ((OP(c) == NBOUND ? isALNUM_uni(tmp) : isALNUM_LC_uni(tmp)) != 0);
+           tmp = (I32)(s != startpos) ? utf8_to_uv(reghop((U8*)s, -1), 0) : '\n';
+           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;
-               else if (regtry(prog, s))
+               else if ((norun || regtry(prog, s)))
                    goto got_it;
                s += UTF8SKIP(s);
            }
-           if ((minlen || !tmp) && regtry(prog,s))
+           if ((!prog->minlen && !tmp) && (norun || regtry(prog, s)))
                goto got_it;
            break;
        case ALNUM:
            while (s < strend) {
                if (isALNUM(*s)) {
-                   if (tmp && regtry(prog, s))
+                   if (tmp && (norun || regtry(prog, s)))
                        goto got_it;
                    else
                        tmp = doevery;
@@ -693,7 +941,7 @@ regexec_flags(register regexp *prog, char *stringarg, register char *strend,
        case ALNUMUTF8:
            while (s < strend) {
                if (swash_fetch(PL_utf8_alnum, (U8*)s)) {
-                   if (tmp && regtry(prog, s))
+                   if (tmp && (norun || regtry(prog, s)))
                        goto got_it;
                    else
                        tmp = doevery;
@@ -707,7 +955,7 @@ regexec_flags(register regexp *prog, char *stringarg, register char *strend,
            PL_reg_flags |= RF_tainted;
            while (s < strend) {
                if (isALNUM_LC(*s)) {
-                   if (tmp && regtry(prog, s))
+                   if (tmp && (norun || regtry(prog, s)))
                        goto got_it;
                    else
                        tmp = doevery;
@@ -721,7 +969,7 @@ regexec_flags(register regexp *prog, char *stringarg, register char *strend,
            PL_reg_flags |= RF_tainted;
            while (s < strend) {
                if (isALNUM_LC_utf8((U8*)s)) {
-                   if (tmp && regtry(prog, s))
+                   if (tmp && (norun || regtry(prog, s)))
                        goto got_it;
                    else
                        tmp = doevery;
@@ -734,7 +982,7 @@ regexec_flags(register regexp *prog, char *stringarg, register char *strend,
        case NALNUM:
            while (s < strend) {
                if (!isALNUM(*s)) {
-                   if (tmp && regtry(prog, s))
+                   if (tmp && (norun || regtry(prog, s)))
                        goto got_it;
                    else
                        tmp = doevery;
@@ -747,7 +995,7 @@ regexec_flags(register regexp *prog, char *stringarg, register char *strend,
        case NALNUMUTF8:
            while (s < strend) {
                if (!swash_fetch(PL_utf8_alnum, (U8*)s)) {
-                   if (tmp && regtry(prog, s))
+                   if (tmp && (norun || regtry(prog, s)))
                        goto got_it;
                    else
                        tmp = doevery;
@@ -761,7 +1009,7 @@ regexec_flags(register regexp *prog, char *stringarg, register char *strend,
            PL_reg_flags |= RF_tainted;
            while (s < strend) {
                if (!isALNUM_LC(*s)) {
-                   if (tmp && regtry(prog, s))
+                   if (tmp && (norun || regtry(prog, s)))
                        goto got_it;
                    else
                        tmp = doevery;
@@ -775,7 +1023,7 @@ regexec_flags(register regexp *prog, char *stringarg, register char *strend,
            PL_reg_flags |= RF_tainted;
            while (s < strend) {
                if (!isALNUM_LC_utf8((U8*)s)) {
-                   if (tmp && regtry(prog, s))
+                   if (tmp && (norun || regtry(prog, s)))
                        goto got_it;
                    else
                        tmp = doevery;
@@ -788,7 +1036,7 @@ regexec_flags(register regexp *prog, char *stringarg, register char *strend,
        case SPACE:
            while (s < strend) {
                if (isSPACE(*s)) {
-                   if (tmp && regtry(prog, s))
+                   if (tmp && (norun || regtry(prog, s)))
                        goto got_it;
                    else
                        tmp = doevery;
@@ -801,7 +1049,7 @@ regexec_flags(register regexp *prog, char *stringarg, register char *strend,
        case SPACEUTF8:
            while (s < strend) {
                if (*s == ' ' || swash_fetch(PL_utf8_space,(U8*)s)) {
-                   if (tmp && regtry(prog, s))
+                   if (tmp && (norun || regtry(prog, s)))
                        goto got_it;
                    else
                        tmp = doevery;
@@ -815,7 +1063,7 @@ regexec_flags(register regexp *prog, char *stringarg, register char *strend,
            PL_reg_flags |= RF_tainted;
            while (s < strend) {
                if (isSPACE_LC(*s)) {
-                   if (tmp && regtry(prog, s))
+                   if (tmp && (norun || regtry(prog, s)))
                        goto got_it;
                    else
                        tmp = doevery;
@@ -829,7 +1077,7 @@ regexec_flags(register regexp *prog, char *stringarg, register char *strend,
            PL_reg_flags |= RF_tainted;
            while (s < strend) {
                if (*s == ' ' || isSPACE_LC_utf8((U8*)s)) {
-                   if (tmp && regtry(prog, s))
+                   if (tmp && (norun || regtry(prog, s)))
                        goto got_it;
                    else
                        tmp = doevery;
@@ -842,7 +1090,7 @@ regexec_flags(register regexp *prog, char *stringarg, register char *strend,
        case NSPACE:
            while (s < strend) {
                if (!isSPACE(*s)) {
-                   if (tmp && regtry(prog, s))
+                   if (tmp && (norun || regtry(prog, s)))
                        goto got_it;
                    else
                        tmp = doevery;
@@ -855,7 +1103,7 @@ regexec_flags(register regexp *prog, char *stringarg, register char *strend,
        case NSPACEUTF8:
            while (s < strend) {
                if (!(*s == ' ' || swash_fetch(PL_utf8_space,(U8*)s))) {
-                   if (tmp && regtry(prog, s))
+                   if (tmp && (norun || regtry(prog, s)))
                        goto got_it;
                    else
                        tmp = doevery;
@@ -869,83 +1117,411 @@ regexec_flags(register regexp *prog, char *stringarg, register char *strend,
            PL_reg_flags |= RF_tainted;
            while (s < strend) {
                if (!isSPACE_LC(*s)) {
-                   if (tmp && regtry(prog, s))
+                   if (tmp && (norun || regtry(prog, s)))
+                       goto got_it;
+                   else
+                       tmp = doevery;
+               }
+               else
+                   tmp = 1;
+               s++;
+           }
+           break;
+       case NSPACELUTF8:
+           PL_reg_flags |= RF_tainted;
+           while (s < strend) {
+               if (!(*s == ' ' || isSPACE_LC_utf8((U8*)s))) {
+                   if (tmp && (norun || regtry(prog, s)))
+                       goto got_it;
+                   else
+                       tmp = doevery;
+               }
+               else
+                   tmp = 1;
+               s += UTF8SKIP(s);
+           }
+           break;
+       case DIGIT:
+           while (s < strend) {
+               if (isDIGIT(*s)) {
+                   if (tmp && (norun || regtry(prog, s)))
+                       goto got_it;
+                   else
+                       tmp = doevery;
+               }
+               else
+                   tmp = 1;
+               s++;
+           }
+           break;
+       case DIGITUTF8:
+           while (s < strend) {
+               if (swash_fetch(PL_utf8_digit,(U8*)s)) {
+                   if (tmp && (norun || regtry(prog, s)))
+                       goto got_it;
+                   else
+                       tmp = doevery;
+               }
+               else
+                   tmp = 1;
+               s += UTF8SKIP(s);
+           }
+           break;
+       case DIGITL:
+           PL_reg_flags |= RF_tainted;
+           while (s < strend) {
+               if (isDIGIT_LC(*s)) {
+                   if (tmp && (norun || regtry(prog, s)))
+                       goto got_it;
+                   else
+                       tmp = doevery;
+               }
+               else
+                   tmp = 1;
+               s++;
+           }
+           break;
+       case DIGITLUTF8:
+           PL_reg_flags |= RF_tainted;
+           while (s < strend) {
+               if (isDIGIT_LC_utf8((U8*)s)) {
+                   if (tmp && (norun || regtry(prog, s)))
+                       goto got_it;
+                   else
+                       tmp = doevery;
+               }
+               else
+                   tmp = 1;
+               s += UTF8SKIP(s);
+           }
+           break;
+       case NDIGIT:
+           while (s < strend) {
+               if (!isDIGIT(*s)) {
+                   if (tmp && (norun || regtry(prog, s)))
+                       goto got_it;
+                   else
+                       tmp = doevery;
+               }
+               else
+                   tmp = 1;
+               s++;
+           }
+           break;
+       case NDIGITUTF8:
+           while (s < strend) {
+               if (!swash_fetch(PL_utf8_digit,(U8*)s)) {
+                   if (tmp && (norun || regtry(prog, s)))
+                       goto got_it;
+                   else
+                       tmp = doevery;
+               }
+               else
+                   tmp = 1;
+               s += UTF8SKIP(s);
+           }
+           break;
+       case NDIGITL:
+           PL_reg_flags |= RF_tainted;
+           while (s < strend) {
+               if (!isDIGIT_LC(*s)) {
+                   if (tmp && (norun || regtry(prog, s)))
+                       goto got_it;
+                   else
+                       tmp = doevery;
+               }
+               else
+                   tmp = 1;
+               s++;
+           }
+           break;
+       case NDIGITLUTF8:
+           PL_reg_flags |= RF_tainted;
+           while (s < strend) {
+               if (!isDIGIT_LC_utf8((U8*)s)) {
+                   if (tmp && (norun || regtry(prog, s)))
+                       goto got_it;
+                   else
+                       tmp = doevery;
+               }
+               else
+                   tmp = 1;
+               s += UTF8SKIP(s);
+           }
+           break;
+       default:
+           Perl_croak(aTHX_ "panic: unknown regstclass %d", (int)OP(c));
+           break;
+       }
+       return 0;
+      got_it:
+       return s;
+}
+
+/*
+ - regexec_flags - match a regexp against a string
+ */
+I32
+Perl_regexec_flags(pTHX_ register regexp *prog, char *stringarg, register char *strend,
+             char *strbeg, I32 minend, SV *sv, void *data, U32 flags)
+/* strend: pointer to null at end of string */
+/* strbeg: real beginning of string */
+/* minend: end of match must be >=minend after stringarg. */
+/* data: May be used for some additional optimizations. */
+/* nosave: For optimizations. */
+{
+    dTHR;
+    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
+                                        constant substr. */            /* CC */
+    I32 end_shift = 0;                 /* Same for the end. */         /* CC */
+    I32 scream_pos = -1;               /* Internal iterator of scream. */
+    char *scream_olds;
+    SV* oreplsv = GvSV(PL_replgv);
+
+    PL_regcc = 0;
+
+    cache_re(prog);
+#ifdef DEBUGGING
+    PL_regnarrate = PL_debug & 512;
+#endif
+
+    /* Be paranoid... */
+    if (prog == NULL || startpos == NULL) {
+       Perl_croak(aTHX_ "NULL regexp parameter");
+       return 0;
+    }
+
+    minlen = prog->minlen;
+    if (strend - startpos < minlen) goto phooey;
+
+    if (startpos == strbeg)    /* is ^ valid at stringarg? */
+       PL_regprev = '\n';
+    else {
+       PL_regprev = (U32)stringarg[-1];
+       if (!PL_multiline && PL_regprev == '\n')
+           PL_regprev = '\0';          /* force ^ to NOT match */
+    }
+
+    /* Check validity of program. */
+    if (UCHARAT(prog->program) != REG_MAGIC) {
+       Perl_croak(aTHX_ "corrupted regexp program");
+    }
+
+    PL_reg_flags = 0;
+    PL_reg_eval_set = 0;
+    PL_reg_maxiter = 0;
+
+    if (prog->reganch & ROPT_UTF8)
+       PL_reg_flags |= RF_utf8;
+
+    /* Mark beginning of line for ^ and lookbehind. */
+    PL_regbol = startpos;
+    PL_bostr  = strbeg;
+    PL_reg_sv = sv;
+
+    /* Mark end of line for $ (and such) */
+    PL_regeol = strend;
+
+    /* see how far we have to get to not match where we matched before */
+    PL_regtill = startpos+minend;
+
+    /* We start without call_cc context.  */
+    PL_reg_call_cc = 0;
+
+    /* If there is a "must appear" string, look for it. */
+    s = startpos;
+
+    if (prog->reganch & ROPT_GPOS_SEEN) { /* Need to have PL_reg_ganch */
+       MAGIC *mg;
+
+       if (flags & REXEC_IGNOREPOS)    /* Means: check only at start */
+           PL_reg_ganch = startpos;
+       else if (sv && SvTYPE(sv) >= SVt_PVMG
+                 && SvMAGIC(sv)
+                 && (mg = mg_find(sv, 'g')) && mg->mg_len >= 0) {
+           PL_reg_ganch = strbeg + mg->mg_len; /* Defined pos() */
+           if (prog->reganch & ROPT_ANCH_GPOS) {
+               if (s > PL_reg_ganch)
+                   goto phooey;
+               s = PL_reg_ganch;
+           }
+       }
+       else                            /* pos() not defined */
+           PL_reg_ganch = strbeg;
+    }
+
+    if (!(flags & REXEC_CHECKED) && prog->check_substr != Nullsv) {
+       re_scream_pos_data d;
+
+       d.scream_olds = &scream_olds;
+       d.scream_pos = &scream_pos;
+       s = re_intuit_start(prog, sv, s, strend, flags, &d);
+       if (!s)
+           goto phooey;        /* not present */
+    }
+
+    DEBUG_r( if (!PL_colorset) reginitcolors() );
+    DEBUG_r(PerlIO_printf(Perl_debug_log,
+                     "%sMatching REx%s `%s%.60s%s%s' against `%s%.*s%s%s'\n",
+                     PL_colors[4],PL_colors[5],PL_colors[0],
+                     prog->precomp,
+                     PL_colors[1],
+                     (strlen(prog->precomp) > 60 ? "..." : ""),
+                     PL_colors[0],
+                     (int)(strend - startpos > 60 ? 60 : strend - startpos),
+                     startpos, PL_colors[1],
+                     (strend - startpos > 60 ? "..." : ""))
+       );
+
+    /* Simplest case:  anchored match need be tried only once. */
+    /*  [unless only anchor is BOL and multiline is set] */
+    if (prog->reganch & (ROPT_ANCH & ~ROPT_ANCH_GPOS)) {
+       if (s == startpos && regtry(prog, startpos))
+           goto got_it;
+       else if (PL_multiline || (prog->reganch & ROPT_IMPLICIT)
+                || (prog->reganch & ROPT_ANCH_MBOL)) /* XXXX SBOL? */
+       {
+           char *end;
+
+           if (minlen)
+               dontbother = minlen - 1;
+           end = HOPc(strend, -dontbother) - 1;
+           /* for multiline we only have to try after newlines */
+           if (prog->check_substr) {
+               if (s == startpos)
+                   goto after_try;
+               while (1) {
+                   if (regtry(prog, s))
                        goto got_it;
+                 after_try:
+                   if (s >= end)
+                       goto phooey;
+                   if (prog->reganch & RE_USE_INTUIT) {
+                       s = re_intuit_start(prog, sv, s + 1, strend, flags, NULL);
+                       if (!s)
+                           goto phooey;
+                   }
                    else
-                       tmp = doevery;
-               }
-               else
-                   tmp = 1;
-               s++;
+                       s++;
+               }               
+           } else {
+               if (s > startpos)
+                   s--;
+               while (s < end) {
+                   if (*s++ == '\n') { /* don't need PL_utf8skip here */
+                       if (regtry(prog, s))
+                           goto got_it;
+                   }
+               }               
            }
-           break;
-       case NSPACELUTF8:
-           PL_reg_flags |= RF_tainted;
+       }
+       goto phooey;
+    } else if (prog->reganch & ROPT_ANCH_GPOS) {
+       if (regtry(prog, PL_reg_ganch))
+           goto got_it;
+       goto phooey;
+    }
+
+    /* Messy cases:  unanchored match. */
+    if (prog->anchored_substr && prog->reganch & ROPT_SKIP) { 
+       /* we have /x+whatever/ */
+       /* it must be a one character string (XXXX Except UTF?) */
+       char ch = SvPVX(prog->anchored_substr)[0];
+       if (UTF) {
            while (s < strend) {
-               if (!(*s == ' ' || isSPACE_LC_utf8((U8*)s))) {
-                   if (tmp && regtry(prog, s))
-                       goto got_it;
-                   else
-                       tmp = doevery;
+               if (*s == ch) {
+                   if (regtry(prog, s)) goto got_it;
+                   s += UTF8SKIP(s);
+                   while (s < strend && *s == ch)
+                       s += UTF8SKIP(s);
                }
-               else
-                   tmp = 1;
                s += UTF8SKIP(s);
            }
-           break;
-       case DIGIT:
+       }
+       else {
            while (s < strend) {
-               if (isDIGIT(*s)) {
-                   if (tmp && regtry(prog, s))
-                       goto got_it;
-                   else
-                       tmp = doevery;
+               if (*s == ch) {
+                   if (regtry(prog, s)) goto got_it;
+                   s++;
+                   while (s < strend && *s == ch)
+                       s++;
                }
-               else
-                   tmp = 1;
                s++;
            }
-           break;
-       case DIGITUTF8:
-           while (s < strend) {
-               if (swash_fetch(PL_utf8_digit,(U8*)s)) {
-                   if (tmp && regtry(prog, s))
-                       goto got_it;
-                   else
-                       tmp = doevery;
-               }
-               else
-                   tmp = 1;
-               s += UTF8SKIP(s);
+       }
+    }
+    /*SUPPRESS 560*/
+    else if (prog->anchored_substr != Nullsv
+            || (prog->float_substr != Nullsv 
+                && prog->float_max_offset < strend - s)) {
+       SV *must = prog->anchored_substr 
+           ? prog->anchored_substr : prog->float_substr;
+       I32 back_max = 
+           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 */
+
+       if (s > PL_bostr)
+           last1 = HOPc(s, -1);
+       else
+           last1 = s - 1;      /* bogus */
+
+       /* XXXX check_substr already used to find `s', can optimize if
+          check_substr==must. */
+       scream_pos = -1;
+       dontbother = end_shift;
+       strend = HOPc(strend, -dontbother);
+       while ( (s <= last) &&
+               ((flags & REXEC_SCREAM) 
+                ? (s = screaminstr(sv, must, HOPc(s, back_min) - strbeg,
+                                   end_shift, &scream_pos, 0))
+                : (s = fbm_instr((unsigned char*)HOP(s, back_min),
+                                 (unsigned char*)strend, must, 
+                                 PL_multiline ? FBMrf_MULTILINE : 0))) ) {
+           if (HOPc(s, -back_max) > last1) {
+               last1 = HOPc(s, -back_min);
+               s = HOPc(s, -back_max);
            }
-           break;
-       case NDIGIT:
-           while (s < strend) {
-               if (!isDIGIT(*s)) {
-                   if (tmp && regtry(prog, s))
+           else {
+               char *t = (last1 >= PL_bostr) ? HOPc(last1, 1) : last1 + 1;
+
+               last1 = HOPc(s, -back_min);
+               s = t;          
+           }
+           if (UTF) {
+               while (s <= last1) {
+                   if (regtry(prog, s))
                        goto got_it;
-                   else
-                       tmp = doevery;
+                   s += UTF8SKIP(s);
                }
-               else
-                   tmp = 1;
-               s++;
            }
-           break;
-       case NDIGITUTF8:
-           while (s < strend) {
-               if (!swash_fetch(PL_utf8_digit,(U8*)s)) {
-                   if (tmp && regtry(prog, s))
+           else {
+               while (s <= last1) {
+                   if (regtry(prog, s))
                        goto got_it;
-                   else
-                       tmp = doevery;
+                   s++;
                }
-               else
-                   tmp = 1;
-               s += UTF8SKIP(s);
            }
-           break;
        }
+       goto phooey;
+    }
+    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;
     }
     else {
        dontbother = 0;
@@ -1015,7 +1591,7 @@ got_it:
            sv_setsv(oreplsv, GvSV(PL_replgv));/* So that when GvSV(replgv) is
                                                  restored, the value remains
                                                  the same. */
-       restore_pos(0);
+       restore_pos(aTHXo_ 0);
     }
 
     /* make sure $`, $&, $', and $digit will work later */
@@ -1042,7 +1618,7 @@ got_it:
 
 phooey:
     if (PL_reg_eval_set)
-       restore_pos(0);
+       restore_pos(aTHXo_ 0);
     return 0;
 }
 
@@ -1050,7 +1626,7 @@ phooey:
  - regtry - try match at specific point
  */
 STATIC I32                     /* 0 failure, 1 success */
-regtry(regexp *prog, char *startpos)
+S_regtry(pTHX_ regexp *prog, char *startpos)
 {
     dTHR;
     register I32 i;
@@ -1063,15 +1639,15 @@ regtry(regexp *prog, char *startpos)
 
        PL_reg_eval_set = RS_init;
        DEBUG_r(DEBUG_s(
-           PerlIO_printf(Perl_debug_log, "  setting stack tmpbase at %i\n",
-                         PL_stack_sp - PL_stack_base);
+           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) {
@@ -1091,7 +1667,7 @@ regtry(regexp *prog, char *startpos)
            }
            PL_reg_magic    = mg;
            PL_reg_oldpos   = mg->mg_len;
-           SAVEDESTRUCTOR(restore_pos, 0);
+           SAVEDESTRUCTOR_X(restore_pos, 0);
         }
        if (!PL_reg_curpm)
            New(22,PL_reg_curpm, 1, PMOP);
@@ -1162,7 +1738,7 @@ regtry(regexp *prog, char *startpos)
  * advantage of machines that use a register save mask on subroutine entry.
  */
 STATIC I32                     /* 0 failure, 1 success */
-regmatch(regnode *prog)
+S_regmatch(pTHX_ regnode *prog)
 {
     dTHR;
     register regnode *scan;    /* Current node. */
@@ -1188,11 +1764,19 @@ regmatch(regnode *prog)
 #ifdef DEBUGGING
 #  define sayYES goto yes
 #  define sayNO goto no
+#  define sayYES_FINAL goto yes_final
+#  define sayYES_LOUD  goto yes_loud
+#  define sayNO_FINAL  goto no_final
+#  define sayNO_SILENT goto do_no
 #  define saySAME(x) if (x) goto yes; else goto no
 #  define REPORT_CODE_OFF 24
 #else
 #  define sayYES return 1
 #  define sayNO return 0
+#  define sayYES_FINAL return 1
+#  define sayYES_LOUD  return 1
+#  define sayNO_FINAL  return 0
+#  define sayNO_SILENT return 0
 #  define saySAME(x) return x
 #endif
        DEBUG_r( {
@@ -1219,8 +1803,8 @@ regmatch(regnode *prog)
                pref0_len = pref_len;
            regprop(prop, scan);
            PerlIO_printf(Perl_debug_log, 
-                         "%4i <%s%.*s%s%s%.*s%s%s%s%.*s%s>%*s|%3d:%*s%s\n",
-                         locinput - PL_bostr
+                         "%4"IVdf" <%s%.*s%s%s%.*s%s%s%s%.*s%s>%*s|%3"IVdf":%*s%s\n",
+                         (IV)(locinput - PL_bostr)
                          PL_colors[4], pref0_len, 
                          locinput - pref_len, PL_colors[5],
                          PL_colors[2], pref_len - pref0_len, 
@@ -1229,7 +1813,7 @@ regmatch(regnode *prog)
                          PL_colors[0], l, locinput, PL_colors[1],
                          15 - l - pref_len + 1,
                          "",
-                         scan - PL_regprogram, PL_regindent*2, "",
+                         (IV)(scan - PL_regprogram), PL_regindent*2, "",
                          SvPVX(prop));
        } );
 
@@ -1320,8 +1904,8 @@ regmatch(regnode *prog)
            nextchr = UCHARAT(++locinput);
            break;
        case EXACT:
-           s = (char *) OPERAND(scan);
-           ln = UCHARAT(s++);
+           s = STRING(scan);
+           ln = STR_LEN(scan);
            /* Inline the first character, for speed. */
            if (UCHARAT(s) != nextchr)
                sayNO;
@@ -1336,8 +1920,8 @@ regmatch(regnode *prog)
            PL_reg_flags |= RF_tainted;
            /* FALL THROUGH */
        case EXACTF:
-           s = (char *) OPERAND(scan);
-           ln = UCHARAT(s++);
+           s = STRING(scan);
+           ln = STR_LEN(scan);
 
            if (UTF) {
                char *l = locinput;
@@ -1375,7 +1959,6 @@ regmatch(regnode *prog)
            nextchr = UCHARAT(locinput);
            break;
        case ANYOFUTF8:
-           s = (char *) OPERAND(scan);
            if (!REGINCLASSUTF8(scan, (U8*)locinput))
                sayNO;
            if (locinput >= PL_regeol)
@@ -1384,10 +1967,9 @@ regmatch(regnode *prog)
            nextchr = UCHARAT(locinput);
            break;
        case ANYOF:
-           s = (char *) OPERAND(scan);
            if (nextchr < 0)
                nextchr = UCHARAT(locinput);
-           if (!REGINCLASS(s, nextchr))
+           if (!REGINCLASS(scan, nextchr))
                sayNO;
            if (!nextchr && locinput >= PL_regeol)
                sayNO;
@@ -1564,15 +2146,30 @@ regmatch(regnode *prog)
                sayNO;
            nextchr = UCHARAT(++locinput);
            break;
+       case DIGITL:
+           PL_reg_flags |= RF_tainted;
+           /* FALL THROUGH */
        case DIGIT:
-           if (!isDIGIT(nextchr))
+           if (!nextchr && locinput >= PL_regeol)
+               sayNO;
+           if (!(OP(scan) == DIGIT
+                 ? isDIGIT(nextchr) : isDIGIT_LC(nextchr)))
                sayNO;
            nextchr = UCHARAT(++locinput);
            break;
+       case DIGITLUTF8:
+           PL_reg_flags |= RF_tainted;
+           /* FALL THROUGH */
        case DIGITUTF8:
+           if (!nextchr)
+               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;
@@ -1581,13 +2178,20 @@ regmatch(regnode *prog)
                sayNO;
            nextchr = UCHARAT(++locinput);
            break;
+       case NDIGITL:
+           PL_reg_flags |= RF_tainted;
+           /* FALL THROUGH */
        case NDIGIT:
-           if (!nextchr && locinput >= PL_regeol)
+           if (!nextchr)
                sayNO;
-           if (isDIGIT(nextchr))
+           if (OP(scan) == DIGIT
+               ? isDIGIT(nextchr) : isDIGIT_LC(nextchr))
                sayNO;
            nextchr = UCHARAT(++locinput);
            break;
+       case NDIGITLUTF8:
+           PL_reg_flags |= RF_tainted;
+           /* FALL THROUGH */
        case NDIGITUTF8:
            if (!nextchr && locinput >= PL_regeol)
                sayNO;
@@ -1619,6 +2223,7 @@ regmatch(regnode *prog)
        case REFF:
            n = ARG(scan);  /* which paren pair */
            ln = PL_regstartp[n];
+           PL_reg_leftiter = PL_reg_maxiter;           /* Void cache */
            if (*PL_reglastparen < n || ln == -1)
                sayNO;                  /* Do not match unless seen CLOSEn. */
            if (ln == PL_regendp[n])
@@ -1692,11 +2297,11 @@ regmatch(regnode *prog)
            
            n = ARG(scan);
            PL_op = (OP_4tree*)PL_regdata->data[n];
-           DEBUG_r( PerlIO_printf(Perl_debug_log, "  re_eval 0x%x\n", PL_op) );
+           DEBUG_r( PerlIO_printf(Perl_debug_log, "  re_eval 0x%"UVxf"\n", PTR2UV(PL_op)) );
            PL_curpad = AvARRAY((AV*)PL_regdata->data[n + 2]);
            PL_regendp[0] = PL_reg_magic->mg_len = locinput - PL_bostr;
 
-           CALLRUNOPS();                       /* Scalar context. */
+           CALLRUNOPS(aTHX);                   /* Scalar context. */
            SPAGAIN;
            ret = POPs;
            PUTBACK;
@@ -1709,7 +2314,6 @@ regmatch(regnode *prog)
                    regexp *re;
                    MAGIC *mg = Null(MAGIC*);
                    re_cc_state state;
-                   CURCUR cctmp;
                    CHECKPOINT cp, lastcp;
 
                    if(SvROK(ret) || SvRMAGICAL(ret)) {
@@ -1731,7 +2335,8 @@ regmatch(regnode *prog)
                        I32 onpar = PL_regnpar;
 
                        pm.op_pmflags = 0;
-                       re = CALLREGCOMP(t, t + len, &pm);
+                       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)))
                            sv_magic(ret,(SV*)ReREFCNT_inc(re),'r',0,0);
@@ -1752,9 +2357,7 @@ regmatch(regnode *prog)
                    state.cc = PL_regcc;
                    state.re = PL_reg_re;
 
-                   cctmp.cur = 0;
-                   cctmp.oldcc = 0;
-                   PL_regcc = &cctmp;
+                   PL_regcc = 0;
                    
                    cp = regcppush(0);  /* Save *all* the positions. */
                    REGCP_SET;
@@ -1763,16 +2366,29 @@ regmatch(regnode *prog)
                    *PL_reglastparen = 0;
                    PL_reg_call_cc = &state;
                    PL_reginput = locinput;
+
+                   /* XXXX This is too dramatic a measure... */
+                   PL_reg_maxiter = 0;
+
                    if (regmatch(re->program + 1)) {
+                       /* Even though we succeeded, we need to restore
+                          global variables, since we may be wrapped inside
+                          SUSPEND, thus the match may be not finished yet. */
+
+                       /* XXXX Do this only if SUSPENDed? */
+                       PL_reg_call_cc = state.prev;
+                       PL_regcc = state.cc;
+                       PL_reg_re = state.re;
+                       cache_re(PL_reg_re);
+
+                       /* XXXX This is too dramatic a measure... */
+                       PL_reg_maxiter = 0;
+
+                       /* These are needed even if not SUSPEND. */
                        ReREFCNT_dec(re);
                        regcpblow(cp);
                        sayYES;
                    }
-                   DEBUG_r(
-                       PerlIO_printf(Perl_debug_log,
-                                     "%*s  failed...\n",
-                                     REPORT_CODE_OFF+PL_regindent*2, "")
-                       );
                    ReREFCNT_dec(re);
                    REGCP_UNWIND;
                    regcppop();
@@ -1780,6 +2396,10 @@ regmatch(regnode *prog)
                    PL_regcc = state.cc;
                    PL_reg_re = state.re;
                    cache_re(PL_reg_re);
+
+                   /* XXXX This is too dramatic a measure... */
+                   PL_reg_maxiter = 0;
+
                    sayNO;
                }
                sw = SvTRUE(ret);
@@ -1807,6 +2427,7 @@ regmatch(regnode *prog)
            sw = (*PL_reglastparen >= n && PL_regendp[n] != -1);
            break;
        case IFTHEN:
+           PL_reg_leftiter = PL_reg_maxiter;           /* Void cache */
            if (sw)
                next = NEXTOPER(NEXTOPER(scan));
            else {
@@ -1818,6 +2439,81 @@ regmatch(regnode *prog)
        case LOGICAL:
            logical = scan->flags;
            break;
+/*******************************************************************
+ PL_regcc contains infoblock about the innermost (...)* loop, and
+ a pointer to the next outer infoblock.
+
+ Here is how Y(A)*Z is processed (if it is compiled into CURLYX/WHILEM):
+
+   1) After matching X, regnode for CURLYX is processed;
+
+   2) This regnode creates infoblock on the stack, and calls 
+      regmatch() recursively with the starting point at WHILEM node;
+
+   3) Each hit of WHILEM node tries to match A and Z (in the order
+      depending on the current iteration, min/max of {min,max} and
+      greediness).  The information about where are nodes for "A"
+      and "Z" is read from the infoblock, as is info on how many times "A"
+      was already matched, and greediness.
+
+   4) After A matches, the same WHILEM node is hit again.
+
+   5) Each time WHILEM is hit, PL_regcc is the infoblock created by CURLYX
+      of the same pair.  Thus when WHILEM tries to match Z, it temporarily
+      resets PL_regcc, since this Y(A)*Z can be a part of some other loop:
+      as in (Y(A)*Z)*.  If Z matches, the automaton will hit the WHILEM node
+      of the external loop.
+
+ Currently present infoblocks form a tree with a stem formed by PL_curcc
+ and whatever it mentions via ->next, and additional attached trees
+ corresponding to temporarily unset infoblocks as in "5" above.
+
+ In the following picture infoblocks for outer loop of 
+ (Y(A)*?Z)*?T are denoted O, for inner I.  NULL starting block
+ is denoted by x.  The matched string is YAAZYAZT.  Temporarily postponed
+ infoblocks are drawn below the "reset" infoblock.
+
+ In fact in the picture below we do not show failed matches for Z and T
+ by WHILEM blocks.  [We illustrate minimal matches, since for them it is
+ more obvious *why* one needs to *temporary* unset infoblocks.]
+
+  Matched      REx position    InfoBlocks      Comment
+               (Y(A)*?Z)*?T    x
+               Y(A)*?Z)*?T     x <- O
+  Y            (A)*?Z)*?T      x <- O
+  Y            A)*?Z)*?T       x <- O <- I
+  YA           )*?Z)*?T        x <- O <- I
+  YA           A)*?Z)*?T       x <- O <- I
+  YAA          )*?Z)*?T        x <- O <- I
+  YAA          Z)*?T           x <- O          # Temporary unset I
+                                    I
+
+  YAAZ         Y(A)*?Z)*?T     x <- O
+                                    I
+
+  YAAZY                (A)*?Z)*?T      x <- O
+                                    I
+
+  YAAZY                A)*?Z)*?T       x <- O <- I
+                                    I
+
+  YAAZYA       )*?Z)*?T        x <- O <- I     
+                                    I
+
+  YAAZYA       Z)*?T           x <- O          # Temporary unset I
+                                    I,I
+
+  YAAZYAZ      )*?T            x <- O
+                                    I,I
+
+  YAAZYAZ      T               x               # Temporary unset O
+                               O
+                               I,I
+
+  YAAZYAZT                     x
+                               O
+                               I,I
+ *******************************************************************/
        case CURLYX: {
                CURCUR cc;
                CHECKPOINT cp = PL_savestack_ix;
@@ -1845,7 +2541,7 @@ regmatch(regnode *prog)
                /*
                 * This is really hard to understand, because after we match
                 * what we're trying to match, we must make sure the rest of
-                * the RE is going to match for sure, and to do that we have
+                * the REx is going to match for sure, and to do that we have
                 * to go back UP the parse tree by recursing ever deeper.  And
                 * if it fails, we have to reset our parent's current state
                 * that we can try again after backing off.
@@ -1870,7 +2566,8 @@ regmatch(regnode *prog)
 
                if (locinput == cc->lastloc && n >= cc->min) {
                    PL_regcc = cc->oldcc;
-                   ln = PL_regcc->cur;
+                   if (PL_regcc)
+                       ln = PL_regcc->cur;
                    DEBUG_r(
                        PerlIO_printf(Perl_debug_log,
                           "%*s  empty match detected, try continuation...\n",
@@ -1878,12 +2575,8 @@ regmatch(regnode *prog)
                        );
                    if (regmatch(cc->next))
                        sayYES;
-                   DEBUG_r(
-                       PerlIO_printf(Perl_debug_log,
-                                     "%*s  failed...\n",
-                                     REPORT_CODE_OFF+PL_regindent*2, "")
-                       );
-                   PL_regcc->cur = ln;
+                   if (PL_regcc)
+                       PL_regcc->cur = ln;
                    PL_regcc = cc;
                    sayNO;
                }
@@ -1897,19 +2590,60 @@ regmatch(regnode *prog)
                        sayYES;
                    cc->cur = n - 1;
                    cc->lastloc = lastloc;
+                   sayNO;
+               }
+
+               if (scan->flags) {
+                   /* Check whether we already were at this position.
+                       Postpone detection until we know the match is not
+                       *that* much linear. */
+               if (!PL_reg_maxiter) {
+                   PL_reg_maxiter = (PL_regeol - PL_bostr + 1) * (scan->flags>>4);
+                   PL_reg_leftiter = PL_reg_maxiter;
+               }
+               if (PL_reg_leftiter-- == 0) {
+                   I32 size = (PL_reg_maxiter + 7)/8;
+                   if (PL_reg_poscache) {
+                       if (PL_reg_poscache_size < size) {
+                           Renew(PL_reg_poscache, size, char);
+                           PL_reg_poscache_size = size;
+                       }
+                       Zero(PL_reg_poscache, size, char);
+                   }
+                   else {
+                       PL_reg_poscache_size = size;
+                       Newz(29, PL_reg_poscache, size, char);
+                   }
+                   DEBUG_r(
+                       PerlIO_printf(Perl_debug_log,
+             "%sDetected a super-linear match, switching on caching%s...\n",
+                                     PL_colors[4], PL_colors[5])
+                       );
+               }
+               if (PL_reg_leftiter < 0) {
+                   I32 o = locinput - PL_bostr, b;
+
+                   o = (scan->flags & 0xf) - 1 + o * (scan->flags>>4);
+                   b = o % 8;
+                   o /= 8;
+                   if (PL_reg_poscache[o] & (1<<b)) {
                    DEBUG_r(
                        PerlIO_printf(Perl_debug_log,
-                                     "%*s  failed...\n",
+                                     "%*s  already tried at this position...\n",
                                      REPORT_CODE_OFF+PL_regindent*2, "")
                        );
-                   sayNO;
+                       sayNO_SILENT;
+                   }
+                   PL_reg_poscache[o] |= (1<<b);
+               }
                }
 
                /* Prefer next over scan for minimal matching. */
 
                if (cc->minmod) {
                    PL_regcc = cc->oldcc;
-                   ln = PL_regcc->cur;
+                   if (PL_regcc)
+                       ln = PL_regcc->cur;
                    cp = regcppush(cc->parenfloor);
                    REGCP_SET;
                    if (regmatch(cc->next)) {
@@ -1918,14 +2652,15 @@ regmatch(regnode *prog)
                    }
                    REGCP_UNWIND;
                    regcppop();
-                   PL_regcc->cur = ln;
+                   if (PL_regcc)
+                       PL_regcc->cur = ln;
                    PL_regcc = cc;
 
                    if (n >= cc->max) { /* Maximum greed exceeded? */
                        if (ckWARN(WARN_UNSAFE) && n >= REG_INFTY 
                            && !(PL_reg_flags & RF_warned)) {
                            PL_reg_flags |= RF_warned;
-                           warner(WARN_UNSAFE, "%s limit (%d) exceeded",
+                           Perl_warner(aTHX_ WARN_UNSAFE, "%s limit (%d) exceeded",
                                 "Complex regular subexpression recursion",
                                 REG_INFTY - 1);
                        }
@@ -1947,11 +2682,6 @@ regmatch(regnode *prog)
                        regcpblow(cp);
                        sayYES;
                    }
-                   DEBUG_r(
-                       PerlIO_printf(Perl_debug_log,
-                                     "%*s  failed...\n",
-                                     REPORT_CODE_OFF+PL_regindent*2, "")
-                       );
                    REGCP_UNWIND;
                    regcppop();
                    cc->cur = n - 1;
@@ -1982,21 +2712,19 @@ regmatch(regnode *prog)
                if (ckWARN(WARN_UNSAFE) && n >= REG_INFTY 
                        && !(PL_reg_flags & RF_warned)) {
                    PL_reg_flags |= RF_warned;
-                   warner(WARN_UNSAFE, "%s limit (%d) exceeded",
+                   Perl_warner(aTHX_ WARN_UNSAFE, "%s limit (%d) exceeded",
                         "Complex regular subexpression recursion",
                         REG_INFTY - 1);
                }
 
                /* Failed deeper matches of scan, so see if this one works. */
                PL_regcc = cc->oldcc;
-               ln = PL_regcc->cur;
+               if (PL_regcc)
+                   ln = PL_regcc->cur;
                if (regmatch(cc->next))
                    sayYES;
-               DEBUG_r(
-                   PerlIO_printf(Perl_debug_log, "%*s  failed...\n",
-                                 REPORT_CODE_OFF+PL_regindent*2, "")
-                   );
-               PL_regcc->cur = ln;
+               if (PL_regcc)
+                   PL_regcc->cur = ln;
                PL_regcc = cc;
                cc->cur = n - 1;
                cc->lastloc = lastloc;
@@ -2081,7 +2809,7 @@ regmatch(regnode *prog)
                    ln = n;
                locinput = PL_reginput;
                if (PL_regkind[(U8)OP(next)] == EXACT) {
-                   c1 = UCHARAT(OPERAND(next) + 1);
+                   c1 = (U8)*STRING(next);
                    if (OP(next) == EXACTF)
                        c2 = PL_fold[c1];
                    else if (OP(next) == EXACTFL)
@@ -2133,12 +2861,13 @@ regmatch(regnode *prog)
                locinput = PL_reginput;
                DEBUG_r(
                    PerlIO_printf(Perl_debug_log,
-                                 "%*s  matched %ld times, len=%ld...\n",
-                                 REPORT_CODE_OFF+PL_regindent*2, "", n, l)
+                                 "%*s  matched %"IVdf" times, len=%"IVdf"...\n",
+                                 (int)(REPORT_CODE_OFF+PL_regindent*2), "",
+                                 (IV) n, (IV)l)
                    );
                if (n >= ln) {
                    if (PL_regkind[(U8)OP(next)] == EXACT) {
-                       c1 = UCHARAT(OPERAND(next) + 1);
+                       c1 = (U8)*STRING(next);
                        if (OP(next) == EXACTF)
                            c2 = PL_fold[c1];
                        else if (OP(next) == EXACTFL)
@@ -2158,8 +2887,8 @@ regmatch(regnode *prog)
                    {
                        DEBUG_r(
                                PerlIO_printf(Perl_debug_log,
-                                             "%*s  trying tail with n=%ld...\n",
-                                             REPORT_CODE_OFF+PL_regindent*2, "", n)
+                                             "%*s  trying tail with n=%"IVdf"...\n",
+                                             (int)(REPORT_CODE_OFF+PL_regindent*2), "", (IV)n)
                            );
                        if (paren) {
                            if (n) {
@@ -2215,7 +2944,7 @@ regmatch(regnode *prog)
            * when we know what character comes next.
            */
            if (PL_regkind[(U8)OP(next)] == EXACT) {
-               c1 = UCHARAT(OPERAND(next) + 1);
+               c1 = (U8)*STRING(next);
                if (OP(next) == EXACTF)
                    c2 = PL_fold[c1];
                else if (OP(next) == EXACTFL)
@@ -2389,14 +3118,22 @@ regmatch(regnode *prog)
                                  "%*s  continuation failed...\n",
                                  REPORT_CODE_OFF+PL_regindent*2, "")
                    );
-               sayNO;
+               sayNO_SILENT;
            }
-           if (locinput < PL_regtill)
-               sayNO;                  /* Cannot match: too short. */
-           /* Fall through */
+           if (locinput < PL_regtill) {
+               DEBUG_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),
+                                     PL_colors[5]));
+               sayNO_FINAL;            /* Cannot match: too short. */
+           }
+           PL_reginput = locinput;     /* put where regtry can find it */
+           sayYES_FINAL;               /* Success! */
        case SUCCEED:
            PL_reginput = locinput;     /* put where regtry can find it */
-           sayYES;                     /* Success! */
+           sayYES_LOUD;                /* Success! */
        case SUSPEND:
            n = 1;
            PL_reginput = locinput;
@@ -2472,9 +3209,9 @@ regmatch(regnode *prog)
                next = NULL;
            break;
        default:
-           PerlIO_printf(PerlIO_stderr(), "%lx %d\n",
-                         (unsigned long)scan, OP(scan));
-           croak("regexp memory corruption");
+           PerlIO_printf(Perl_error_log, "%"UVxf" %d\n",
+                         PTR2UV(scan), OP(scan));
+           Perl_croak(aTHX_ "regexp memory corruption");
        }
        scan = next;
     }
@@ -2483,10 +3220,20 @@ regmatch(regnode *prog)
     * We get here only if there's trouble -- normally "case END" is
     * the terminating point.
     */
-    croak("corrupted regexp pointers");
+    Perl_croak(aTHX_ "corrupted regexp pointers");
     /*NOTREACHED*/
     sayNO;
 
+yes_loud:
+    DEBUG_r(
+       PerlIO_printf(Perl_debug_log,
+                     "%*s  %scould match...%s\n",
+                     REPORT_CODE_OFF+PL_regindent*2, "", PL_colors[4],PL_colors[5])
+       );
+    goto yes;
+yes_final:
+    DEBUG_r(PerlIO_printf(Perl_debug_log, "%sMatch successful!%s\n",
+                         PL_colors[4],PL_colors[5]));
 yes:
 #ifdef DEBUGGING
     PL_regindent--;
@@ -2494,6 +3241,14 @@ yes:
     return 1;
 
 no:
+    DEBUG_r(
+       PerlIO_printf(Perl_debug_log,
+                     "%*s  %sfailed...%s\n",
+                     REPORT_CODE_OFF+PL_regindent*2, "",PL_colors[4],PL_colors[5])
+       );
+    goto do_no;
+no_final:
+do_no:
 #ifdef DEBUGGING
     PL_regindent--;
 #endif
@@ -2509,11 +3264,10 @@ no:
  * rather than incrementing count on every character.  [Er, except utf8.]]
  */
 STATIC I32
-regrepeat(regnode *p, I32 max)
+S_regrepeat(pTHX_ regnode *p, I32 max)
 {
     dTHR;
     register char *scan;
-    register char *opnd;
     register I32 c;
     register char *loceol = PL_regeol;
     register I32 hardcount = 0;
@@ -2521,7 +3275,6 @@ regrepeat(regnode *p, I32 max)
     scan = PL_reginput;
     if (max != REG_INFTY && max < loceol - scan)
       loceol = scan + max;
-    opnd = (char *) OPERAND(p);
     switch (OP(p)) {
     case REG_ANY:
        while (scan < loceol && *scan != '\n')
@@ -2545,19 +3298,19 @@ regrepeat(regnode *p, I32 max)
        }
        break;
     case EXACT:                /* length of string is 1 */
-       c = UCHARAT(++opnd);
+       c = (U8)*STRING(p);
        while (scan < loceol && UCHARAT(scan) == c)
            scan++;
        break;
     case EXACTF:       /* length of string is 1 */
-       c = UCHARAT(++opnd);
+       c = (U8)*STRING(p);
        while (scan < loceol &&
               (UCHARAT(scan) == c || UCHARAT(scan) == PL_fold[c]))
            scan++;
        break;
     case EXACTFL:      /* length of string is 1 */
        PL_reg_flags |= RF_tainted;
-       c = UCHARAT(++opnd);
+       c = (U8)*STRING(p);
        while (scan < loceol &&
               (UCHARAT(scan) == c || UCHARAT(scan) == PL_fold_locale[c]))
            scan++;
@@ -2570,7 +3323,7 @@ regrepeat(regnode *p, I32 max)
        }
        break;
     case ANYOF:
-       while (scan < loceol && REGINCLASS(opnd, *scan))
+       while (scan < loceol && REGINCLASS(p, *scan))
            scan++;
        break;
     case ALNUM:
@@ -2709,8 +3462,8 @@ regrepeat(regnode *p, I32 max)
 
                regprop(prop, p);
                PerlIO_printf(Perl_debug_log, 
-                             "%*s  %s can match %ld times out of %ld...\n", 
-                             REPORT_CODE_OFF+1, "", SvPVX(prop),c,max);
+                             "%*s  %s can match %"IVdf" times out of %"IVdf"...\n", 
+                             REPORT_CODE_OFF+1, "", SvPVX(prop),(IV)c,(IV)max);
        });
     
     return(c);
@@ -2723,7 +3476,7 @@ regrepeat(regnode *p, I32 max)
  */
 
 STATIC I32
-regrepeat_hard(regnode *p, I32 max, I32 *lp)
+S_regrepeat_hard(pTHX_ regnode *p, I32 max, I32 *lp)
 {
     dTHR;
     register char *scan;
@@ -2774,14 +3527,14 @@ regrepeat_hard(regnode *p, I32 max, I32 *lp)
  */
 
 STATIC bool
-reginclass(register char *p, register I32 c)
+S_reginclass(pTHX_ register regnode *p, register I32 c)
 {
     dTHR;
-    char flags = *p;
+    char flags = ANYOF_FLAGS(p);
     bool match = FALSE;
 
     c &= 0xFF;
-    if (ANYOF_TEST(p, c))
+    if (ANYOF_BITMAP_TEST(p, c))
        match = TRUE;
     else if (flags & ANYOF_FOLD) {
        I32 cf;
@@ -2791,17 +3544,40 @@ reginclass(register char *p, register I32 c)
        }
        else
            cf = PL_fold[c];
-       if (ANYOF_TEST(p, cf))
+       if (ANYOF_BITMAP_TEST(p, cf))
            match = TRUE;
     }
 
-    if (!match && (flags & ANYOF_ISA)) {
+    if (!match && (flags & ANYOF_CLASS)) {
        PL_reg_flags |= RF_tainted;
-
-       if (((flags & ANYOF_ALNUML)  && isALNUM_LC(c))  ||
-           ((flags & ANYOF_NALNUML) && !isALNUM_LC(c)) ||
-           ((flags & ANYOF_SPACEL)  && isSPACE_LC(c))  ||
-           ((flags & ANYOF_NSPACEL) && !isSPACE_LC(c)))
+       if (
+           (ANYOF_CLASS_TEST(p, ANYOF_ALNUM)   &&  isALNUM_LC(c))  ||
+           (ANYOF_CLASS_TEST(p, ANYOF_NALNUM)  && !isALNUM_LC(c))  ||
+           (ANYOF_CLASS_TEST(p, ANYOF_SPACE)   &&  isSPACE_LC(c))  ||
+           (ANYOF_CLASS_TEST(p, ANYOF_NSPACE)  && !isSPACE_LC(c))  ||
+           (ANYOF_CLASS_TEST(p, ANYOF_DIGIT)   &&  isDIGIT_LC(c))  ||
+           (ANYOF_CLASS_TEST(p, ANYOF_NDIGIT)  && !isDIGIT_LC(c))  ||
+           (ANYOF_CLASS_TEST(p, ANYOF_ALNUMC)  &&  isALNUMC_LC(c)) ||
+           (ANYOF_CLASS_TEST(p, ANYOF_NALNUMC) && !isALNUMC_LC(c)) ||
+           (ANYOF_CLASS_TEST(p, ANYOF_ALPHA)   &&  isALPHA_LC(c))  ||
+           (ANYOF_CLASS_TEST(p, ANYOF_NALPHA)  && !isALPHA_LC(c))  ||
+           (ANYOF_CLASS_TEST(p, ANYOF_ASCII)   &&  isASCII(c))     ||
+           (ANYOF_CLASS_TEST(p, ANYOF_NASCII)  && !isASCII(c))     ||
+           (ANYOF_CLASS_TEST(p, ANYOF_CNTRL)   &&  isCNTRL_LC(c))  ||
+           (ANYOF_CLASS_TEST(p, ANYOF_NCNTRL)  && !isCNTRL_LC(c))  ||
+           (ANYOF_CLASS_TEST(p, ANYOF_GRAPH)   &&  isGRAPH_LC(c))  ||
+           (ANYOF_CLASS_TEST(p, ANYOF_NGRAPH)  && !isGRAPH_LC(c))  ||
+           (ANYOF_CLASS_TEST(p, ANYOF_LOWER)   &&  isLOWER_LC(c))  ||
+           (ANYOF_CLASS_TEST(p, ANYOF_NLOWER)  && !isLOWER_LC(c))  ||
+           (ANYOF_CLASS_TEST(p, ANYOF_PRINT)   &&  isPRINT_LC(c))  ||
+           (ANYOF_CLASS_TEST(p, ANYOF_NPRINT)  && !isPRINT_LC(c))  ||
+           (ANYOF_CLASS_TEST(p, ANYOF_PUNCT)   &&  isPUNCT_LC(c))  ||
+           (ANYOF_CLASS_TEST(p, ANYOF_NPUNCT)  && !isPUNCT_LC(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))
+           ) /* How's that for a conditional? */
        {
            match = TRUE;
        }
@@ -2811,7 +3587,7 @@ reginclass(register char *p, register I32 c)
 }
 
 STATIC bool
-reginclassutf8(regnode *f, U8 *p)
+S_reginclassutf8(pTHX_ regnode *f, U8 *p)
 {                                           
     dTHR;
     char flags = ARG1(f);
@@ -2833,23 +3609,13 @@ reginclassutf8(regnode *f, U8 *p)
            match = TRUE;
     }
 
-    if (!match && (flags & ANYOF_ISA)) {
-       PL_reg_flags |= RF_tainted;
-
-       if (((flags & ANYOF_ALNUML)  && isALNUM_LC_utf8(p))  ||
-           ((flags & ANYOF_NALNUML) && !isALNUM_LC_utf8(p)) ||
-           ((flags & ANYOF_SPACEL)  && isSPACE_LC_utf8(p))  ||
-           ((flags & ANYOF_NSPACEL) && !isSPACE_LC_utf8(p)))
-       {
-           match = TRUE;
-       }
-    }
+    /* UTF8 combined with ANYOF_CLASS is ill-defined. */
 
     return (flags & ANYOF_INVERT) ? !match : match;
 }
 
 STATIC U8 *
-reghop(U8 *s, I32 off)
+S_reghop(pTHX_ U8 *s, I32 off)
 {                               
     dTHR;
     if (off >= 0) {
@@ -2871,7 +3637,7 @@ reghop(U8 *s, I32 off)
 }
 
 STATIC U8 *
-reghopmaybe(U8* s, I32 off)
+S_reghopmaybe(pTHX_ U8* s, I32 off)
 {
     dTHR;
     if (off >= 0) {
@@ -2897,3 +3663,24 @@ reghopmaybe(U8* s, I32 off)
     }
     return s;
 }
+
+#ifdef PERL_OBJECT
+#include "XSUB.h"
+#endif
+
+static void
+restore_pos(pTHXo_ void *arg)
+{
+    dTHR;
+    if (PL_reg_eval_set) {
+       if (PL_reg_oldsaved) {
+           PL_reg_re->subbeg = PL_reg_oldsaved;
+           PL_reg_re->sublen = PL_reg_oldsavedlen;
+           RX_MATCH_COPIED_on(PL_reg_re);
+       }
+       PL_reg_magic->mg_len = PL_reg_oldpos;
+       PL_reg_eval_set = 0;
+       PL_curpm = PL_reg_oldcurpm;
+    }  
+}
+