From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (qmail 14624 invoked by alias); 10 Mar 2014 22:19:05 -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 14570 invoked by uid 48); 10 Mar 2014 22:18:59 -0000 From: "grosser at gcc dot gnu.org" To: gcc-bugs@gcc.gnu.org Subject: [Bug tree-optimization/59121] [4.8/4.9 Regression] endless loop with -O2 -floop-parallelize-all Date: Mon, 10 Mar 2014 22:19:00 -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: 4.8.1 X-Bugzilla-Keywords: compile-time-hog X-Bugzilla-Severity: normal X-Bugzilla-Who: grosser at gcc dot gnu.org X-Bugzilla-Status: NEW X-Bugzilla-Priority: P4 X-Bugzilla-Assigned-To: unassigned at gcc dot gnu.org X-Bugzilla-Target-Milestone: 4.8.3 X-Bugzilla-Flags: X-Bugzilla-Changed-Fields: cc 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: 2014-03/txt/msg00850.txt.bz2 http://gcc.gnu.org/bugzilla/show_bug.cgi?id=59121 Tobias Grosser changed: What |Removed |Added ---------------------------------------------------------------------------- CC| |grosser at gcc dot gnu.org --- Comment #16 from Tobias Grosser --- (In reply to Jeffrey A. Law from comment #15) > Mircea, thanks. I'm definitely looking forward to seeing Graphite in a > better state! With you on board at INRIA and working on Graphite, I will > not be calling for Graphite's removal after the 4.9 release. > > Thanks again, > jeff This bug is probably the perfect case to use isl's new compute out facility, which allows us to give up after a certain number of compute iterations. This will give us the assurance that we do not hang any more in the graphite dependence analysis, but that we instead bail out smoothly. We should probably also work on the efficiency of the analysis (and there is a lot that could be done), but in my opinion the number one priority is that we avoid unpredictable compile time. After this issue is fixed, we can address cases where we bail out as missed optimizations. Something, that is a lot less intrusive.