From: Jarkko Hietaniemi <jhi@iki.fi>
Date: Sat, 13 Nov 1999 19:43:37 +0000 (+0000)
Subject: Integrate with Sarathy.
X-Git-Url: http://git.shadowcat.co.uk/gitweb/gitweb.cgi?a=commitdiff_plain;h=374d691e102e2975cdf0ae9698b9f6e2ad73d91c;p=p5sagit%2Fp5-mst-13.2.git

Integrate with Sarathy.

p4raw-id: //depot/cfgperl@4576
---

374d691e102e2975cdf0ae9698b9f6e2ad73d91c
diff --cc regexec.c
index fa891c8,fa891c8..e3f0cb4
--- a/regexec.c
+++ b/regexec.c
@@@ -254,6 -254,6 +254,9 @@@ S_cache_re(pTHX_ regexp *prog
      PL_reg_re = prog;    
  }
  
++static char *find_byclass(regexp * prog, regnode *c, char *s, char *strend,
++			  char *startpos, I32 norun);
++
  /* 
   * Need to implement the following flags for reg_anch:
   *
@@@ -275,6 -275,6 +278,13 @@@
  
  /* XXXX We assume that strpos is strbeg unless sv. */
  
++/* 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.) */
++
  /* 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
@@@ -285,10 -285,10 +295,14 @@@
  	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', multiline-part of 'c', and try to find a position in the
++   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.
   */
  
++/* 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. */
++
  char *
  Perl_re_intuit_start(pTHX_ regexp *prog, SV *sv, char *strpos,
  		     char *strend, U32 flags, re_scream_pos_data *data)
@@@ -301,7 -301,7 +315,8 @@@
      char *t;
      I32 ml_anch;
      char *tmp;
--    register char *other_last = Nullch;
++    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
@@@ -432,6 -432,6 +447,8 @@@
      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)) );
  
@@@ -447,7 -447,7 +464,7 @@@
  	/* Take into account the "other" substring. */
  	/* XXXX May be hopelessly wrong for UTF... */
  	if (!other_last)
--	    other_last = strpos - 1;
++	    other_last = strpos;
  	if (check == prog->float_substr) {
  	  do_other_anchored:
  	    {
@@@ -465,8 -465,8 +482,8 @@@
  		else
  		    t = strpos;
  		t += prog->anchored_offset;
--		if (t <= other_last)
--		    t = other_last + 1;
++		if (t < other_last)	/* These positions already checked */
++		    t = other_last;
  		PL_bostr = tmp;
  		last2 = last1 = strend - prog->minlen;
  		if (last < last1)
@@@ -495,7 -495,7 +512,7 @@@
  			", trying floating at offset %ld...\n",
  			(long)(s1 + 1 - i_strpos)));
  		    PL_regeol = strend;			/* Used in HOP() */
--		    other_last = last1 + prog->anchored_offset;
++		    other_last = last1 + prog->anchored_offset + 1;
  		    s = HOPc(last, 1);
  		    goto restart;
  		}
@@@ -503,7 -503,7 +520,7 @@@
  		    DEBUG_r(PerlIO_printf(Perl_debug_log, " at offset %ld...\n",
  			  (long)(s - i_strpos)));
  		    t = s - prog->anchored_offset;
--		    other_last = s - 1;
++		    other_last = s + 1;
  		    s = s1;
  		    if (t == strpos)
  			goto try_at_start;
@@@ -520,8 -520,8 +537,8 @@@
  		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 + 1;
++		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,
@@@ -546,7 -546,7 +563,7 @@@
  		    DEBUG_r(PerlIO_printf(Perl_debug_log,
  			", trying anchored starting at offset %ld...\n",
  			(long)(s1 + 1 - i_strpos)));
--		    other_last = last;
++		    other_last = last + 1;
  		    PL_regeol = strend;			/* Used in HOP() */
  		    s = HOPc(t, 1);
  		    goto restart;
@@@ -554,7 -554,7 +571,7 @@@
  		else {
  		    DEBUG_r(PerlIO_printf(Perl_debug_log, " at offset %ld...\n",
  			  (long)(s - i_strpos)));
--		    other_last = s - 1;
++		    other_last = s + 1;
  		    s = s1;
  		    if (t == strpos)
  			goto try_at_start;
@@@ -652,6 -652,6 +669,72 @@@
  	    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().  */
++	char *endpos = (prog->anchored_substr || ml_anch)
++		? s + (prog->minlen? 1 : 0)
++		: (prog->float_substr ? check_at - start_shift + 1
++				      : strend) ;
++	char *startpos = sv ? strend - SvCUR(sv) : s;
++
++	t = s;
++        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;
++	    }
++	    /* Contradict one of substrings */
++	    if (prog->anchored_substr) {
++		DEBUG_r( PerlIO_printf(Perl_debug_log,
++				"This position contradicts STCLASS...\n") );
++		if (prog->anchored_substr == check) {
++		    DEBUG_r( what = "anchored" );
++		  hop_and_restart:
++		    PL_regeol = strend;	/* Used in HOP() */
++		    s = HOPc(t, 1);
++		    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 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;
++	    }
++	    /* Check is floating subtring. */
++	  retry_floating_check:
++	    t = check_at - start_shift;
++	    DEBUG_r( what = "floating" );
++	    goto hop_and_restart;
++	}
++	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") );
++    }
      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;
@@@ -983,7 -983,7 +1066,7 @@@ Perl_regexec_flags(pTHX_ register regex
  			 && (ln == 1 || (OP(c) == EXACTF
  					 ? ibcmp(s, m, ln)
  					 : ibcmp_locale(s, m, ln)))
--			 && regtry(prog, s) )
++			 && (norun || regtry(prog, s)) )
  			goto got_it;
  		    s++;
  		}
@@@ -993,7 -993,7 +1076,7 @@@
  			 && (ln == 1 || (OP(c) == EXACTF
  					 ? ibcmp(s, m, ln)
  					 : ibcmp_locale(s, m, ln)))
--			 && regtry(prog, s) )
++			 && (norun || regtry(prog, s)) )
  			goto got_it;
  		    s++;
  		}
@@@ -1003,32 -1003,32 +1086,24 @@@
  	    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 = (I32)(s != startpos) ? utf8_to_uv(reghop((U8*)s, -1), 0) : '\n';
  	    tmp = ((OP(c) == BOUND ? isALNUM_uni(tmp) : isALNUM_LC_uni(tmp)) != 0);
  	    while (s < strend) {
  		if (tmp == !(OP(c) == BOUND ?
@@@ -1036,60 -1036,60 +1111,54 @@@
  			     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++;
++	    if (prog->minlen)
  		strend = reghop_c(strend, -1);
--	    }
--	    tmp = (I32)(s != startpos) ? utf8_to_uv(reghop((U8*)s, -1), 0) : PL_regprev;
++	    tmp = (I32)(s != startpos) ? utf8_to_uv(reghop((U8*)s, -1), 0) : '\n';
  	    tmp = ((OP(c) == NBOUND ? isALNUM_uni(tmp) : isALNUM_LC_uni(tmp)) != 0);
  	    while (s < strend) {
  		if (tmp == !(OP(c) == NBOUND ?
  			     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;
@@@ -1102,7 -1102,7 +1171,7 @@@
  	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;
@@@ -1116,7 -1116,7 +1185,7 @@@
  	    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;
@@@ -1130,7 -1130,7 +1199,7 @@@
  	    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;
@@@ -1143,7 -1143,7 +1212,7 @@@
  	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;
@@@ -1156,7 -1156,7 +1225,7 @@@
  	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;
@@@ -1170,7 -1170,7 +1239,7 @@@
  	    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;
@@@ -1184,7 -1184,7 +1253,7 @@@
  	    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;
@@@ -1197,7 -1197,7 +1266,7 @@@
  	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;
@@@ -1210,7 -1210,7 +1279,7 @@@
  	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;
@@@ -1224,7 -1224,7 +1293,7 @@@
  	    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;
@@@ -1238,7 -1238,7 +1307,7 @@@
  	    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;
@@@ -1251,7 -1251,7 +1320,7 @@@
  	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;
@@@ -1264,7 -1264,7 +1333,7 @@@
  	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;
@@@ -1278,7 -1278,7 +1347,7 @@@
  	    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;
@@@ -1292,7 -1292,7 +1361,7 @@@
  	    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;
@@@ -1305,7 -1305,7 +1374,7 @@@
  	case DIGIT:
  	    while (s < strend) {
  		if (isDIGIT(*s)) {
--		    if (tmp && regtry(prog, s))
++		    if (tmp && (norun || regtry(prog, s)))
  			goto got_it;
  		    else
  			tmp = doevery;
@@@ -1318,7 -1318,7 +1387,7 @@@
  	case DIGITUTF8:
  	    while (s < strend) {
  		if (swash_fetch(PL_utf8_digit,(U8*)s)) {
--		    if (tmp && regtry(prog, s))
++		    if (tmp && (norun || regtry(prog, s)))
  			goto got_it;
  		    else
  			tmp = doevery;
@@@ -1332,7 -1332,7 +1401,7 @@@
  	    PL_reg_flags |= RF_tainted;
  	    while (s < strend) {
  		if (isDIGIT_LC(*s)) {
--		    if (tmp && regtry(prog, s))
++		    if (tmp && (norun || regtry(prog, s)))
  			goto got_it;
  		    else
  			tmp = doevery;
@@@ -1346,7 -1346,7 +1415,7 @@@
  	    PL_reg_flags |= RF_tainted;
  	    while (s < strend) {
  		if (isDIGIT_LC_utf8((U8*)s)) {
--		    if (tmp && regtry(prog, s))
++		    if (tmp && (norun || regtry(prog, s)))
  			goto got_it;
  		    else
  			tmp = doevery;
@@@ -1359,7 -1359,7 +1428,7 @@@
  	case NDIGIT:
  	    while (s < strend) {
  		if (!isDIGIT(*s)) {
--		    if (tmp && regtry(prog, s))
++		    if (tmp && (norun || regtry(prog, s)))
  			goto got_it;
  		    else
  			tmp = doevery;
@@@ -1372,7 -1372,7 +1441,7 @@@
  	case NDIGITUTF8:
  	    while (s < strend) {
  		if (!swash_fetch(PL_utf8_digit,(U8*)s)) {
--		    if (tmp && regtry(prog, s))
++		    if (tmp && (norun || regtry(prog, s)))
  			goto got_it;
  		    else
  			tmp = doevery;
@@@ -1386,7 -1386,7 +1455,7 @@@
  	    PL_reg_flags |= RF_tainted;
  	    while (s < strend) {
  		if (!isDIGIT_LC(*s)) {
--		    if (tmp && regtry(prog, s))
++		    if (tmp && (norun || regtry(prog, s)))
  			goto got_it;
  		    else
  			tmp = doevery;
@@@ -1400,7 -1400,7 +1469,7 @@@
  	    PL_reg_flags |= RF_tainted;
  	    while (s < strend) {
  		if (!isDIGIT_LC_utf8((U8*)s)) {
--		    if (tmp && regtry(prog, s))
++		    if (tmp && (norun || regtry(prog, s)))
  			goto got_it;
  		    else
  			tmp = doevery;
@@@ -1414,6 -1414,6 +1483,270 @@@
  	    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],
++		      (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;
++		    s = re_intuit_start(prog, sv, s + 1, strend, flags, NULL);
++		    if (!s)
++			goto phooey;
++		}		
++	    } else {
++		if (s > startpos)
++		    s--;
++		while (s < end) {
++		    if (*s++ == '\n') {	/* don't need PL_utf8skip here */
++			if (regtry(prog, s))
++			    goto got_it;
++		    }
++		}		
++	    }
++	}
++	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 == ch) {
++		    if (regtry(prog, s)) goto got_it;
++		    s += UTF8SKIP(s);
++		    while (s < strend && *s == ch)
++			s += UTF8SKIP(s);
++		}
++		s += UTF8SKIP(s);
++	    }
++	}
++	else {
++	    while (s < strend) {
++		if (*s == ch) {
++		    if (regtry(prog, s)) goto got_it;
++		    s++;
++		    while (s < strend && *s == ch)
++			s++;
++		}
++		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);
++	    }
++	    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);
++		}
++	    }
++	    else {
++		while (s <= last1) {
++		    if (regtry(prog, s))
++			goto got_it;
++		    s++;
++		}
++	    }
++	}
++	goto phooey;
++    }
++    else if (c = prog->regstclass) {
++	if (minlen)		/* 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;
diff --cc t/op/re_tests
index d72a0f7,d72a0f7..f866385
--- a/t/op/re_tests
+++ b/t/op/re_tests
@@@ -742,3 -742,3 +742,5 @@@ tt+$	xxxtt	y	-	
  ([[:digit:]-z]+)	=0-z=	y	$1	0-z
  ([[:digit:]-[:alpha:]]+)	=0-z=	y	$1	0-z
  \GX.*X	aaaXbX	n	-	-
++(\d+\.\d+)	3.1415926	y	$1	3.1415926
++(\ba.{0,10}br)	have a web browser	y	$1	a web br