remove double stringify-overload from $ovld .= foo

There was a piece of code in pp_concat who's job it was to determine the
UT8ness of the LHS, and it did it in a heavy-handed way to cope with the
special case of a regexp (which is an RV pointing to REGEXP which might
be UTF8)

1 files changed, 2 insertions, 3 deletions

diff --git a/pp_hot.c b/pp_hot.c
index 29928d7201..0e529215a3 100644
--- a/pp_hot.c
+++ b/pp_hot.c
@@ -255,14 +255,13 @@ PP(pp_concat)
 	    SvUTF8_off(TARG);
     }
     else { /* TARG == left */
-        STRLEN llen;
 	if (!SvOK(TARG)) {
 	    if (left == right && ckWARN(WARN_UNINITIALIZED))
 		report_uninit(right);
 	    sv_setpvs(left, "");
 	}
-	(void)SvPV_nomg_const(left, llen);    /* Needed to set UTF8 flag */
-	lbyte = !DO_UTF8(left);
+	lbyte = (SvROK(left) && SvTYPE(SvRV(left)) == SVt_REGEXP)
+		    ?  !DO_UTF8(SvRV(left)) : !DO_UTF8(left);
 	if (IN_BYTES)
 	    SvUTF8_off(TARG);
     }