"don't recompile pattern" check: account for UTF8

When recompiling a pattern (e.g. for $x (x,y) { /$x/ }),
it tests whether the new pattern string matches the old one, and if so
skips recompiling it. However, it doesn't take account of the UTF8ness of
the old and new patterns, so can falsely skip recompiling. Now fixed.

Also, there is a feature in re_op_compile() that may abort a pattern
compilation, upgrade the pattern to UTF8, then begin the compile again.
I've added a second check for whether the pattern matches the old pattern,
against the upgraded string. I can't see a way to test this, since its
just an optimisation.  Arguably I could add a BEGIN in an embedded code
block to see if it gets compiled twice, but soon I'm going to make it so
that embedded code blocks always get recompiled anyway.

1 files changed, 1 insertions, 1 deletions

diff --git a/proto.h b/proto.h
index ccab428804..3db372433d 100644
--- a/proto.h
+++ b/proto.h
@@ -3150,7 +3150,7 @@ PERL_CALLCONV SV*	Perl_re_intuit_string(pTHX_ REGEXP  *const r)
 #define PERL_ARGS_ASSERT_RE_INTUIT_STRING	\
 	assert(r)
 
-PERL_CALLCONV REGEXP*	Perl_re_op_compile(pTHX_ SV ** const patternp, int pat_count, OP *expr, const regexp_engine* eng, REGEXP *old_re, int *is_bare_re, U32 flags);
+PERL_CALLCONV REGEXP*	Perl_re_op_compile(pTHX_ SV ** const patternp, int pat_count, OP *expr, const regexp_engine* eng, REGEXP *VOL old_re, int *is_bare_re, U32 flags);
 PERL_CALLCONV Malloc_t	Perl_realloc(Malloc_t where, MEM_SIZE nbytes)
 			__attribute__malloc__
 			__attribute__warn_unused_result__;