regcomp.c: Use latin1 folding in synthetic start class

This is because the pattern may not specify unicode semantics, but if
the target matching string is in utf8, then unicode semantics may be
needed nonetheless.  So to avoid the regexec optimizer rejecting the
match, we need to allow for a possible false positive.

diff --git a/regcomp.c b/regcomp.c
index 79623d2..392b075 100644 (file)
--- a/regcomp.c
+++ b/regcomp.c
@@ -3073,11 +3073,18 @@ S_study_chunk(pTHX_ RExC_state_t *pRExC_state, regnode **scanp,
                /* Check whether it is compatible with what we know already! */
                int compat = 1;
 
+
+               /* If compatibile, we or it in below.  It is compatible if is
+                * in the bitmp and either 1) its bit or its fold is set, or 2)
+                * it's for a locale.  Even if there isn't unicode semantics
+                * here, at runtime there may be because of matching against a
+                * utf8 string, so accept a possible false positive for
+                * latin1-range folds */
                if (uc >= 0x100 ||
                    (!(data->start_class->flags & (ANYOF_CLASS | ANYOF_LOCALE))
                    && !ANYOF_BITMAP_TEST(data->start_class, uc)
                    && (!(data->start_class->flags & ANYOF_FOLD)
-                       || !ANYOF_BITMAP_TEST(data->start_class, (UNI_SEMANTICS) ? PL_fold_latin1[uc] : PL_fold[uc])))
+                       || !ANYOF_BITMAP_TEST(data->start_class, PL_fold_latin1[uc])))
                     )
                    compat = 0;
                ANYOF_CLASS_ZERO(data->start_class);
@@ -3119,12 +3126,13 @@ S_study_chunk(pTHX_ RExC_state_t *pRExC_state, regnode **scanp,
            if (flags & SCF_DO_STCLASS_AND) {
                /* Check whether it is compatible with what we know already! */
                int compat = 1;
-
                if (uc >= 0x100 ||
-                   (!(data->start_class->flags & (ANYOF_CLASS | ANYOF_LOCALE))
-                   && !ANYOF_BITMAP_TEST(data->start_class, uc)
-                    && !ANYOF_BITMAP_TEST(data->start_class, (UNI_SEMANTICS) ? PL_fold_latin1[uc] : PL_fold[uc])))
+                (!(data->start_class->flags & (ANYOF_CLASS | ANYOF_LOCALE))
+                 && !ANYOF_BITMAP_TEST(data->start_class, uc)
+                 && !ANYOF_BITMAP_TEST(data->start_class, PL_fold_latin1[uc])))
+               {
                    compat = 0;
+               }
                ANYOF_CLASS_ZERO(data->start_class);
                ANYOF_BITMAP_ZERO(data->start_class);
                if (compat) {
@@ -3136,13 +3144,11 @@ S_study_chunk(pTHX_ RExC_state_t *pRExC_state, regnode **scanp,
                    }
                    else {
 
-                       /* Also set the other member of the fold pair.  Can't
-                        * do this for locale, because not known until runtime
-                        */
-                       ANYOF_BITMAP_SET(data->start_class,
-                                        (OP(scan) == EXACTFU)
-                                                   ? PL_fold_latin1[uc]
-                                                   : PL_fold[uc]);
+                       /* Also set the other member of the fold pair.  In case
+                        * that unicode semantics is called for at runtime, use
+                        * the full latin1 fold.  (Can't do this for locale,
+                        * because not known until runtime */
+                       ANYOF_BITMAP_SET(data->start_class, PL_fold_latin1[uc]);
                    }
                }
            }
@@ -3158,9 +3164,7 @@ S_study_chunk(pTHX_ RExC_state_t *pRExC_state, regnode **scanp,
                              * can't do that in locale because not known until
                              * run-time */
                             ANYOF_BITMAP_SET(data->start_class,
-                                            (OP(scan) == EXACTFU)
-                                                        ? PL_fold_latin1[uc]
-                                                        : PL_fold[uc]);
+                                            PL_fold_latin1[uc]);
                         }
                    }
                    data->start_class->flags &= ~ANYOF_EOS;