sv.c: Convert to use is_utf8_invariant_string_loc

This inline function was added in the previous commit.

And the function has the potential to be sped up by using word-at-a-time
operations.

diff --git a/sv.c b/sv.c
index 2617eba..4df1224 100644 (file)
--- a/sv.c
+++ b/sv.c
@@ -3496,20 +3496,16 @@ Perl_sv_utf8_upgrade_flags_grow(pTHX_ SV *const sv, const I32 flags, STRLEN extr
         * incoming SV being well formed and having a trailing '\0', as certain
         * code in pp_formline can send us partially built SVs. */
 
-       while (t < e) {
-           const U8 ch = *t++;
-           if (NATIVE_BYTE_IS_INVARIANT(ch)) continue;
+       if (is_utf8_invariant_string_loc(s, SvCUR(sv), (const U8 **) &t)) {
 
-           t--;    /* t already incremented; re-point to first variant */
-           two_byte_count = 1;
-           goto must_be_utf8;
+            /* utf8 conversion not needed because all are invariants.  Mark as
+             * UTF-8 even if no variant - saves scanning loop */
+            SvUTF8_on(sv);
+            if (extra) SvGROW(sv, SvCUR(sv) + extra);
+            return SvCUR(sv);
        }
 
-       /* utf8 conversion not needed because all are invariants.  Mark as
-        * UTF-8 even if no variant - saves scanning loop */
-       SvUTF8_on(sv);
-       if (extra) SvGROW(sv, SvCUR(sv) + extra);
-       return SvCUR(sv);
+        two_byte_count = 1;
 
       must_be_utf8: