fix accidental pessimization in RE optimizer (from Ilya Zakharevich)

p4raw-id: //depot/perl@6151

diff --git a/regexec.c b/regexec.c
index cd3df47..60a5f6c 100644 (file)
--- a/regexec.c
+++ b/regexec.c
@@ -599,9 +599,10 @@ Perl_re_intuit_start(pTHX_ regexp *prog, SV *sv, char *strpos,
          find_anchor:
            while (t < strend - prog->minlen) {
                if (*t == '\n') {
-                   if (t < s - prog->check_offset_min) {
+                   if (t < check_at - prog->check_offset_min) {
                        if (prog->anchored_substr) {
-                           /* We definitely contradict the found anchored
+                           /* Since we moved from the found position,
+                              we definitely contradict the found anchored
                               substr.  Due to the above check we do not
                               contradict "check" substr.
                               Thus we can arrive here only if check substr
@@ -612,12 +613,17 @@ Perl_re_intuit_start(pTHX_ regexp *prog, SV *sv, char *strpos,
                                PL_colors[0],PL_colors[1], (long)(strpos - i_strpos), (long)(strpos - i_strpos + prog->anchored_offset)));
                            goto do_other_anchored;
                        }
+                       /* We don't contradict the found floating substring. */
+                       /* XXXX Why not check for STCLASS? */
                        s = t + 1;
                        DEBUG_r(PerlIO_printf(Perl_debug_log, "Found /%s^%s/m at offset %ld...\n",
                            PL_colors[0],PL_colors[1], (long)(s - i_strpos)));
                        goto set_useful;
                    }
-                   DEBUG_r(PerlIO_printf(Perl_debug_log, "Found /%s^%s/m, restarting at offset %ld...\n",
+                   /* Position contradicts check-string */
+                   /* XXXX probably better to look for check-string
+                      than for "\n", so one should lower the limit for t? */
+                   DEBUG_r(PerlIO_printf(Perl_debug_log, "Found /%s^%s/m, restarting lookup for check-string at offset %ld...\n",
                        PL_colors[0],PL_colors[1], (long)(t + 1 - i_strpos)));
                    strpos = s = t + 1;
                    goto restart;