[perl #45337] utf8 + "[a]a{2}" + /$.../ = panic: sv_len_utf8 cache

when shrinking an SV, shrink the sv_len_utf8 cache too!

p4raw-id: //depot/perl@31867

1 files changed, 1 insertions, 1 deletions

diff --git a/regcomp.c b/regcomp.c
index 358ac8ef07..441d762e6e 100644
--- a/regcomp.c
+++ b/regcomp.c
@@ -3297,7 +3297,7 @@ S_study_chunk(pTHX_ RExC_state_t *pRExC_state, regnode **scanp,
 					SvUTF8(sv) && SvMAGICAL(sv) ?
 					mg_find(sv, PERL_MAGIC_utf8) : NULL;
 				    if (mg && mg->mg_len >= 0)
-					mg->mg_len += CHR_SVLEN(last_str);
+					mg->mg_len += CHR_SVLEN(last_str) - l;
 				}
 				data->last_end += l * (mincount - 1);
 			    }