From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (qmail 19027 invoked by alias); 28 Nov 2011 09:14:10 -0000 Received: (qmail 19016 invoked by uid 22791); 28 Nov 2011 09:14:09 -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, 28 Nov 2011 09:13:54 +0000 From: "jakub at gcc dot gnu.org" To: gcc-bugs@gcc.gnu.org Subject: [Bug tree-optimization/50078] [4.6/4.7 Regression] combine wrong code: volatile accesses optimized out Date: Mon, 28 Nov 2011 09:49:00 -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-Keywords: wrong-code X-Bugzilla-Severity: normal X-Bugzilla-Who: jakub at gcc dot gnu.org X-Bugzilla-Status: ASSIGNED X-Bugzilla-Priority: P2 X-Bugzilla-Assigned-To: jakub at gcc dot gnu.org X-Bugzilla-Target-Milestone: 4.6.3 X-Bugzilla-Changed-Fields: AssignedTo 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 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: 2011-11/txt/msg02628.txt.bz2 http://gcc.gnu.org/bugzilla/show_bug.cgi?id=50078 Jakub Jelinek changed: What |Removed |Added ---------------------------------------------------------------------------- AssignedTo|matz at gcc dot gnu.org |jakub at gcc dot gnu.org --- Comment #10 from Jakub Jelinek 2011-11-28 09:12:39 UTC --- Created attachment 25929 --> http://gcc.gnu.org/bugzilla/attachment.cgi?id=25929 gcc47-pr50078.patch IMHO it is a forwprop bug, which changes a MEM_REF in this case into an ARRAY_REF (with MEM_REF operand), but copies TREE_THIS_VOLATILE from the original MEM_REF not to the ARRAY_REF, but to the inner MEM_REF.