From: Steffen Mueller <smueller@cpan.org>
Date: Mon, 10 Feb 2014 10:40:31 +0000 (+0100)
Subject: pp_concat: Only call SvPV_force_nolen when needed
X-Git-Tag: upstream/5.20.0~446
X-Git-Url: http://review.tizen.org/git/?a=commitdiff_plain;h=18ea7bf2cf79c90c0c3162783e5a0f30fbf0c026;p=platform%2Fupstream%2Fperl.git

pp_concat: Only call SvPV_force_nolen when needed

If we just did an sv_setpvs on it, the SvPV_force_nolen should not do
anything useful, so let's not.

Side note: s/TARG/left/ in the enclosing block because they are the same
pointer, so why use a define that needs grokking by the reader of the
code if the local variable is guaranteed to be the same?
---

diff --git a/pp_hot.c b/pp_hot.c
index beb9649..79b77ab 100644
--- a/pp_hot.c
+++ b/pp_hot.c
@@ -278,16 +278,18 @@ PP(pp_concat)
 	else
 	    SvUTF8_off(TARG);
     }
-    else { /* $l .= $r */
-	if (!SvOK(TARG)) {
+    else { /* $l .= $r   and   left == TARG */
+	if (!SvOK(left)) {
 	    if (left == right && ckWARN(WARN_UNINITIALIZED)) /* $l .= $l */
 		report_uninit(right);
 	    sv_setpvs(left, "");
 	}
-	SvPV_force_nomg_nolen(left);
+        else {
+            SvPV_force_nomg_nolen(left);
+        }
 	lbyte = !DO_UTF8(left);
 	if (IN_BYTES)
-	    SvUTF8_off(TARG);
+	    SvUTF8_off(left);
     }
 
     if (!rcopied) {