From mboxrd@z Thu Jan  1 00:00:00 1970
Return-Path: <gcc-bugs-return-358405-listarch-gcc-bugs=gcc.gnu.org@gcc.gnu.org>
Received: (qmail 15148 invoked by alias); 31 May 2011 08:44:28 -0000
Received: (qmail 15127 invoked by uid 22791); 31 May 2011 08:44:27 -0000
X-SWARE-Spam-Status: No, hits=-2.6 required=5.0	tests=ALL_TRUSTED,AWL,BAYES_00,TW_TM
X-Spam-Check-By: sourceware.org
Received: from localhost (HELO gcc.gnu.org) (127.0.0.1)    by sourceware.org (qpsmtpd/0.43rc1) with ESMTP; Tue, 31 May 2011 08:44:13 +0000
From: "rguenther at suse dot de" <gcc-bugzilla@gcc.gnu.org>
To: gcc-bugs@gcc.gnu.org
Subject: [Bug tree-optimization/49093] [4.6/4.7 Regression] ICE in vect_enhance_data_refs_alignment() with volatile inside peeled loop
X-Bugzilla-Reason: CC
X-Bugzilla-Type: changed
X-Bugzilla-Watch-Reason: None
X-Bugzilla-Product: gcc
X-Bugzilla-Component: tree-optimization
X-Bugzilla-Keywords:
X-Bugzilla-Severity: normal
X-Bugzilla-Who: rguenther at suse dot de
X-Bugzilla-Status: NEW
X-Bugzilla-Priority: P3
X-Bugzilla-Assigned-To: unassigned at gcc dot gnu.org
X-Bugzilla-Target-Milestone: 4.6.1
X-Bugzilla-Changed-Fields:
Message-ID: <bug-49093-4-pztBHC9V8V@http.gcc.gnu.org/bugzilla/>
In-Reply-To: <bug-49093-4@http.gcc.gnu.org/bugzilla/>
References: <bug-49093-4@http.gcc.gnu.org/bugzilla/>
X-Bugzilla-URL: http://gcc.gnu.org/bugzilla/
Auto-Submitted: auto-generated
Content-Type: text/plain; charset="UTF-8"
MIME-Version: 1.0
Date: Tue, 31 May 2011 08:54:00 -0000
Mailing-List: contact gcc-bugs-help@gcc.gnu.org; run by ezmlm
Precedence: bulk
List-Id: <gcc-bugs.gcc.gnu.org>
List-Archive: <http://gcc.gnu.org/ml/gcc-bugs/>
List-Post: <mailto:gcc-bugs@gcc.gnu.org>
List-Help: <mailto:gcc-bugs-help@gcc.gnu.org>
Sender: gcc-bugs-owner@gcc.gnu.org
X-SW-Source: 2011-05/txt/msg03072.txt.bz2

http://gcc.gnu.org/bugzilla/show_bug.cgi?id=49093

--- Comment #6 from rguenther at suse dot de <rguenther at suse dot de> 2011-05-31 08:43:39 UTC ---
On Tue, 31 May 2011, irar at il dot ibm.com wrote:

> http://gcc.gnu.org/bugzilla/show_bug.cgi?id=49093
> 
> --- Comment #5 from Ira Rosen <irar at il dot ibm.com> 2011-05-31 08:30:49 UTC ---
> (In reply to comment #4)
> 
> > I think that's reasonable for 4.6.  But we don't need to make
> > data-ref analysis fail just because of volatile references - we for
> > example can easily unroll a loop with volatile loads/stores.
> > 
> > Of course this case seems to be special - how do we deal with
> > stmts with no uses during vectorization?  Or do we assume
> > they don't happen because usually DCE gets rid of them?
> 
> We ignore them. But this is under the assumption that they don't have memory
> accesses.

Ah, I see.  Yes, I guess not vectorizing for volatiles is the way
to go then.

Richard.