from_utf8 = DO_UTF8(fromstr);
if (from_utf8) {
aend = aptr + fromlen;
- fromlen = sv_len_utf8(fromstr);
+ fromlen = sv_len_utf8_nomg(fromstr);
} else aend = NULL; /* Unused, but keep compilers happy */
GROWING(utf8, cat, start, cur, (fromlen+2) / 3 * 4 + (fromlen+len-1)/len * 2);
while (fromlen > 0) {