From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (qmail 31670 invoked by alias); 13 Dec 2013 13:03:20 -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 31598 invoked by uid 48); 13 Dec 2013 13:03:09 -0000 From: "dominiq at lps dot ens.fr" To: gcc-bugs@gcc.gnu.org Subject: [Bug tree-optimization/59487] [4.9 Regression] When compiled with -fwhole-program rnflow.f90 runs up to 40% slower after r202826 Date: Fri, 13 Dec 2013 13:03:00 -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: 4.9.0 X-Bugzilla-Keywords: X-Bugzilla-Severity: normal X-Bugzilla-Who: dominiq at lps dot ens.fr X-Bugzilla-Status: UNCONFIRMED X-Bugzilla-Priority: P3 X-Bugzilla-Assigned-To: unassigned at gcc dot gnu.org X-Bugzilla-Target-Milestone: 4.9.0 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: 2013-12/txt/msg01158.txt.bz2 http://gcc.gnu.org/bugzilla/show_bug.cgi?id=59487 --- Comment #3 from Dominique d'Humieres --- > r202826 was fixed later by the fix for PR58656 (rnflow regression), > so your bisection converged on a bogus revision. OK! I was too focused on the -fwhole-program option. The slowdown after r202826 was with/without this option. r203377 fixed the regression without the option, but not with it: [Book15] lin/test% /opt/gcc/gcc4.9p-202825/bin/gfortran -Ofast -fwhole-program rnflow.f90 [Book15] lin/test% time a.out > /dev/null 12.843u 0.017s 0:12.86 99.9% 0+0k 0+0io 0pf+0w [Book15] lin/test% /opt/gcc/gcc4.9p-202825/bin/gfortran -Ofast rnflow.f90 [Book15] lin/test% time a.out > /dev/null 12.889u 0.022s 0:12.92 99.8% 0+0k 0+0io 41pf+0w [Book15] lin/test% /opt/gcc/gcc4.9p-202828/bin/gfortran -Ofast rnflow.f90 [Book15] lin/test% time a.out > /dev/null 17.891u 0.019s 0:17.91 99.9% 0+0k 0+0io 0pf+0w [Book15] lin/test% /opt/gcc/gcc4.9p-202828/bin/gfortran -Ofast -fwhole-program rnflow.f90 [Book15] lin/test% time a.out > /dev/null 17.985u 0.021s 0:18.01 99.9% 0+0k 4+0io 41pf+0w [Book15] lin/test% /opt/gcc/gcc4.9p-203250/bin/gfortran -Ofast rnflow.f90 [Book15] lin/test% time a.out > /dev/null 17.974u 0.020s 0:17.99 100.0% 0+0k 0+0io 0pf+0w [Book15] lin/test% /opt/gcc/gcc4.9p-203250/bin/gfortran -Ofast -fwhole-program rnflow.f90 [Book15] lin/test% time a.out > /dev/null 18.182u 0.021s 0:18.21 99.9% 0+0k 0+1io 38pf+0w [Book15] lin/test% /opt/gcc/gcc4.9p-203492/bin/gfortran -Ofast rnflow.f90 [Book15] lin/test% time a.out > /dev/null 12.856u 0.018s 0:12.87 99.9% 0+0k 0+0io 0pf+0w [Book15] lin/test% /opt/gcc/gcc4.9p-203492/bin/gfortran -Ofast -fwhole-program rnflow.f90 [Book15] lin/test% time a.out > /dev/null 18.253u 0.021s 0:18.28 99.9% 0+0k 0+0io 39pf+0w AFAICT the usual incantations ('large-function-growth', 'max-inline-insns-auto', or 'builtin-expect-probability') have no visible effect on this slowdown with -fwhole-program.