From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (qmail 12661 invoked by alias); 2 May 2008 10:29:49 -0000 Received: (qmail 12482 invoked by uid 48); 2 May 2008 10:28:59 -0000 Date: Fri, 02 May 2008 10:29:00 -0000 Message-ID: <20080502102859.12481.qmail@sourceware.org> X-Bugzilla-Reason: CC References: Subject: [Bug tree-optimization/32921] [4.3/4.4 Regression] Revision 126326 causes 12% slowdown In-Reply-To: Reply-To: gcc-bugzilla@gcc.gnu.org To: gcc-bugs@gcc.gnu.org From: "rguenth at gcc dot gnu dot org" 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: 2008-05/txt/msg00084.txt.bz2 ------- Comment #48 from rguenth at gcc dot gnu dot org 2008-05-02 10:28 ------- Btw, on x86_64 leslie3d performance is now above that from before r126326. The differences you mention can be seen on x86_64 as well, but they are not related to aliasing or partitioning but due to differences in what IVOPTs produces. The first difference at all on the tree level is with mergephi2 that is able to remove a single forwarder BB if --param max-aliased-vops=10000 is _not_ specified. First real changes happen when DOM is able to CSE some loads with --param max-aliased-vops=10000 but not without: - D.1747_808 = D.1747_763; - D.1748_809 = D.1748_764; - D.1749_811 = D.1749_766; - D.1750_812 = D.1749_766 * D.1644_799; + D.1747_808 = pav.data; + D.1748_809 = (real(kind=8)[0:] *) D.1747_808; + D.1749_811 = pav.dim[0].stride; + D.1750_812 = D.1644_799 * D.1749_811; and as PRE itself is not alias-oracle aware as well further missed optimizations occur. -- http://gcc.gnu.org/bugzilla/show_bug.cgi?id=32921