From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (qmail 28222 invoked by alias); 21 Oct 2014 11:15:12 -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 28175 invoked by uid 48); 21 Oct 2014 11:15:08 -0000 From: "rguenth at gcc dot gnu.org" To: gcc-bugs@gcc.gnu.org Subject: [Bug tree-optimization/61515] [4.9/5 Regression] Extremely long compile time for generated code Date: Tue, 21 Oct 2014 11:19:00 -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: 5.0 X-Bugzilla-Keywords: compile-time-hog X-Bugzilla-Severity: normal X-Bugzilla-Who: rguenth at gcc dot gnu.org X-Bugzilla-Status: NEW X-Bugzilla-Priority: P2 X-Bugzilla-Assigned-To: law at redhat dot com X-Bugzilla-Target-Milestone: 4.9.2 X-Bugzilla-Flags: X-Bugzilla-Changed-Fields: attachments.created 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: 2014-10/txt/msg01593.txt.bz2 https://gcc.gnu.org/bugzilla/show_bug.cgi?id=61515 --- Comment #20 from Richard Biener --- Created attachment 33766 --> https://gcc.gnu.org/bugzilla/attachment.cgi?id=33766&action=edit non-working patch Of course this still walks all SSA names (but only once per BB), so it isn't really removing the quadraticness. Moreover the patch (see attachment) I was testing fails to bootstrap on the 4.9 branch, seemingly miscompiling stage2 gcc (and crashing in building stage2 libgcc in swap_tree_comparison called from IVOPTs). Eventually record_temporary_equivalences_from_stmts_at_dest depends on the exact ordering of record_temporary_equivalence calls (I do the invaldiate ones late). Jeff? As this is a regression from 4.9.0 appearing in 4.9.1 it's quite bad that this is now still unfixed given we are about to release 4.9.2. I'm out of here again ;)