Fix undefined behaviour in combine.c:force_to_mode

Message ID	201207071230.q67CU9hN026246@d06av02.portsmouth.uk.ibm.com
State	Accepted
Headers	show Return-Path: <patch+caf_=linaro-patchwork=canonical.com@linaro.org> Received-SPF: pass (google.com: domain of uweigand@de.ibm.com designates 195.75.94.111 as permitted sender) client-ip=195.75.94.111; Gateway: Authorized Use Only! Violators will be prosecuted for <patches@linaro.org> from <uweigand@de.ibm.com>; Sat, 7 Jul 2012 13:30:13 +0100 Gateway: Authorized Use Only! Violators will be prosecuted; Sat, 7 Jul 2012 13:30:11 +0100 Message-Id: <201207071230.q67CU9hN026246@d06av02.portsmouth.uk.ibm.com> Subject: [PATCH] Fix undefined behaviour in combine.c:force_to_mode To: patches@linaro.org Date: Sat, 7 Jul 2012 14:30:09 +0200 (CEST) From: "Ulrich Weigand" <uweigand@de.ibm.com> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Transfer-Encoding: 7bit

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Message-Id: <201207071230.q67CU9hN026246@d06av02.portsmouth.uk.ibm.com>
Subject: [PATCH] Fix undefined behaviour in combine.c:force_to_mode
To: patches@linaro.org
Date: Sat, 7 Jul 2012 14:30:09 +0200 (CEST)
From: "Ulrich Weigand" <uweigand@de.ibm.com>
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Commit Message

Ulrich Weigand July 7, 2012, 12:30 p.m. UTC

http://gcc.gnu.org/ml/gcc-patches/2012-07/msg00246.html

ChangeLog:

	* combine.c (force_to_mode) [LSHIFTRT]: Avoid undefined behaviour
	due to negative shift amount.

=== modified file 'gcc/combine.c'
--- gcc/combine.c	2012-02-22 12:22:43 +0000
+++ gcc/combine.c	2012-07-03 19:46:18 +0000
@@ -8432,6 +8432,7 @@ 
 	 in OP_MODE.  */
 
       if (CONST_INT_P (XEXP (x, 1))
+	  && INTVAL (XEXP (x, 1)) >= 0
 	  && INTVAL (XEXP (x, 1)) < HOST_BITS_PER_WIDE_INT
 	  && HWI_COMPUTABLE_MODE_P (op_mode))
 	{

Fix undefined behaviour in combine.c:force_to_mode

Commit Message

Patch