From: Rafael Garcia-Suarez <rgarciasuarez@gmail.com>
Date: Tue, 20 Jan 2009 08:11:18 +0000 (+0100)
Subject: Optimize away calls to empty DESTROY methods
X-Git-Url: http://git.shadowcat.co.uk/gitweb/gitweb.cgi?a=commitdiff_plain;h=fbb3ee5af3d;p=p5sagit%2Fp5-mst-13.2.git

Optimize away calls to empty DESTROY methods
---

diff --git a/sv.c b/sv.c
index d944e2f..ae728b1 100644
--- a/sv.c
+++ b/sv.c
@@ -5655,7 +5655,11 @@ Perl_sv_clear(pTHX_ register SV *const sv)
 		CV* destructor;
 		stash = SvSTASH(sv);
 		destructor = StashHANDLER(stash,DESTROY);
-		if (destructor) {
+		if (destructor
+			/* Don't bother calling an empty destructor */
+			&& (CvISXSUB(destructor)
+			|| CvSTART(destructor)->op_next->op_type != OP_LEAVESUB))
+		{
 		    SV* const tmpref = newRV(sv);
 	            SvREADONLY_on(tmpref);   /* DESTROY() could be naughty */
 		    ENTER;