From: Shenghou Ma <minux.ma@gmail.com>
Date: Wed, 13 Jun 2012 20:24:15 +0000 (-0400)
Subject: [release-branch.go1] cmd/cc: fix uint right shift in constant evaluation
X-Git-Tag: go1.0.2~60
X-Git-Url: http://www.git.cypherpunks.su/?a=commitdiff_plain;h=b260999d4cfd261ce077b1093c61eea7bd6faf57;p=gostls13.git

[release-branch.go1] cmd/cc: fix uint right shift in constant evaluation

««« backport aa2d2fa1e5a9
cmd/cc: fix uint right shift in constant evaluation
        Fixes #3664.

R=golang-dev, bradfitz, rsc
CC=golang-dev
https://golang.org/cl/6249048

»»»
---

diff --git a/src/cmd/cc/scon.c b/src/cmd/cc/scon.c
index 193331f774..f6031a5be7 100644
--- a/src/cmd/cc/scon.c
+++ b/src/cmd/cc/scon.c
@@ -175,7 +175,10 @@ evconst(Node *n)
 		break;
 
 	case OLSHR:
-		v = (uvlong)l->vconst >> r->vconst;
+		if(l->type->width != sizeof(uvlong))
+			v = ((uvlong)l->vconst & 0xffffffffULL) >> r->vconst;
+		else
+			v = (uvlong)l->vconst >> r->vconst;
 		break;
 
 	case OASHR: