From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (qmail 1401 invoked by alias); 3 Jan 2011 20:32:04 -0000 Received: (qmail 1392 invoked by uid 22791); 3 Jan 2011 20:32:04 -0000 X-SWARE-Spam-Status: No, hits=-2.9 required=5.0 tests=ALL_TRUSTED,AWL,BAYES_00 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; Mon, 03 Jan 2011 20:31:59 +0000 From: "rguenth at gcc dot gnu.org" To: gcc-bugs@gcc.gnu.org Subject: [Bug tree-optimization/46781] [4.6 Regression] Missing optimization 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: missed-optimization X-Bugzilla-Severity: normal X-Bugzilla-Who: rguenth at gcc dot gnu.org X-Bugzilla-Status: NEW X-Bugzilla-Priority: P3 X-Bugzilla-Assigned-To: unassigned at gcc dot gnu.org X-Bugzilla-Target-Milestone: 4.6.0 X-Bugzilla-Changed-Fields: Message-ID: In-Reply-To: References: X-Bugzilla-URL: http://gcc.gnu.org/bugzilla/ Auto-Submitted: auto-generated Content-Type: text/plain; charset="UTF-8" MIME-Version: 1.0 Date: Mon, 03 Jan 2011 20:32:00 -0000 Mailing-List: contact gcc-bugs-help@gcc.gnu.org; run by ezmlm Precedence: bulk List-Id: List-Archive: List-Post: List-Help: Sender: gcc-bugs-owner@gcc.gnu.org X-SW-Source: 2011-01/txt/msg00184.txt.bz2 http://gcc.gnu.org/bugzilla/show_bug.cgi?id=46781 --- Comment #4 from Richard Guenther 2011-01-03 20:31:55 UTC --- (In reply to comment #3) > Comment on attachment 22612 [details] > Code produced by GCC 4.6.0 > > (In reply to comment #2) > > Where did you get this testcase from? > > May I know why do you ask? To see if the change indeed causes important regressions in real-world code. The change was done to be less surprising when doing TBAA based disambiguations as people regularly expect void * to be similar to char * and also do not really handle multiple-indirect pointers the correct way. Thus, we now miscompile less not strictly conforming programs. > IIRC, it was distilled from some large program. There was a difference when > compiling it with and without LTO, and I reported it as a bug 43201. Ah, that explains it (LTO did the pointer TBAA thing for a long time).