From mboxrd@z Thu Jan  1 00:00:00 1970
Return-Path: <gcc-bugs-return-439729-listarch-gcc-bugs=gcc.gnu.org@gcc.gnu.org>
Received: (qmail 24861 invoked by alias); 9 Jan 2014 09:34:03 -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
Received: (qmail 24823 invoked by uid 48); 9 Jan 2014 09:34:00 -0000
From: "rguenth at gcc dot gnu.org" <gcc-bugzilla@gcc.gnu.org>
To: gcc-bugs@gcc.gnu.org
Subject: [Bug tree-optimization/59387] [4.9 Regression] wrong code (hangs) at -Os on x86_64-linux-gnu
Date: Thu, 09 Jan 2014 09:34:00 -0000
X-Bugzilla-Reason: CC
X-Bugzilla-Type: changed
X-Bugzilla-Watch-Reason: None
X-Bugzilla-Product: gcc
X-Bugzilla-Component: tree-optimization
X-Bugzilla-Version: 4.9.0
X-Bugzilla-Keywords: wrong-code
X-Bugzilla-Severity: normal
X-Bugzilla-Who: rguenth at gcc dot gnu.org
X-Bugzilla-Status: NEW
X-Bugzilla-Priority: P1
X-Bugzilla-Assigned-To: unassigned at gcc dot gnu.org
X-Bugzilla-Target-Milestone: 4.9.0
X-Bugzilla-Flags:
X-Bugzilla-Changed-Fields:
Message-ID: <bug-59387-4-MmK4T72wkb@http.gcc.gnu.org/bugzilla/>
In-Reply-To: <bug-59387-4@http.gcc.gnu.org/bugzilla/>
References: <bug-59387-4@http.gcc.gnu.org/bugzilla/>
Content-Type: text/plain; charset="UTF-8"
Content-Transfer-Encoding: 7bit
X-Bugzilla-URL: http://gcc.gnu.org/bugzilla/
Auto-Submitted: auto-generated
MIME-Version: 1.0
X-SW-Source: 2014-01/txt/msg00871.txt.bz2

http://gcc.gnu.org/bugzilla/show_bug.cgi?id=59387

--- Comment #8 from Richard Biener <rguenth at gcc dot gnu.org> ---
(In reply to Jakub Jelinek from comment #7)
> Unfortunately it triggers (sccp no longer optimizes) on quite a few
> testcases:
> 
> gcc.c-torture/execute/pr58277-1.c
> gcc.c-torture/execute/pr58831.c
> gcc.c-torture/execute/pr59387.c
> gcc.dg/pr58010.c
> gcc.dg/torture/pr55481.c
> gcc.dg/torture/pr56366.c
> gcc.dg/torture/pr59058.c
> gcc.dg/torture/pr59245.c
> gcc.dg/tree-ssa/loop-32.c
> gcc.dg/tree-ssa/loop-33.c
> gcc.dg/tree-ssa/loop-35.c
> gcc.dg/tree-ssa/scev-6.c
> 
> (the first test only for -m64, all the rest both -m32 and -m64, the last
> even FAILs because of that).  Couldn't we just transform that somehow into
> an unsigned type computation instead in that case, at least for simple cases?

You could leverage the code I added to LIM ... in the case where SCEV folded
casts, of course.