fixes for mortalization bug in xsubpp, other efficiency tweaks

	Message-Id: <H00000e500086fb3@MHS>
	Subject: [PATCH _69] sv_2mortal fix

p4raw-id: //depot/perl@1306

1 files changed, 1 insertions, 1 deletions

diff --git a/pp_hot.c b/pp_hot.c
index 7234f15fdd..6218f85514 100644
--- a/pp_hot.c
+++ b/pp_hot.c
@@ -673,7 +673,7 @@ PP(pp_aassign)
 	default:
 	    if (SvTHINKFIRST(sv)) {
 		if (SvREADONLY(sv) && curcop != &compiling) {
-		    if (sv != &sv_undef && sv != &sv_yes && sv != &sv_no)
+		    if (!SvIMMORTAL(sv))
 			DIE(no_modify);
 		    if (relem <= lastrelem)
 			relem++;