From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (qmail 3706 invoked by alias); 14 Jul 2014 19:15:33 -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 Received: (qmail 3445 invoked by uid 48); 14 Jul 2014 19:15:22 -0000 From: "law at redhat dot com" To: gcc-bugs@gcc.gnu.org Subject: [Bug tree-optimization/61757] [4.10 Regression] genmodes failure with enable-checking Date: Mon, 14 Jul 2014 19:15:00 -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: 4.10.0 X-Bugzilla-Keywords: build X-Bugzilla-Severity: normal X-Bugzilla-Who: law at redhat dot com X-Bugzilla-Status: RESOLVED X-Bugzilla-Priority: P1 X-Bugzilla-Assigned-To: rguenth at gcc dot gnu.org X-Bugzilla-Target-Milestone: 4.10.0 X-Bugzilla-Flags: X-Bugzilla-Changed-Fields: Message-ID: In-Reply-To: References: 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: 2014-07/txt/msg00913.txt.bz2 https://gcc.gnu.org/bugzilla/show_bug.cgi?id=61757 --- Comment #32 from Jeffrey A. Law --- No, we don't have that information available in any reasonable form. That's one of the things I need to investigate. One of the possibilities is to flip things on their side a bit. The old code started recording equivalences it might need to invalidate when it traversed the backedge. Part of the problem with that scheme is some of the equivalences were already recorded by tree-ssa-dom.c, independent of the threading bits. We didn't have a way to find or invalidate those equivalences. One of the things I want to look at is whether or not we can start recording when we process a PHI with arguments that are the targets of backedges. I haven't prototyped any code around that and I'm not sure if we'll have a reasonable separation between DOM and the threading code, but that's the first thing I want to look at once I deal with Teresa's changes.