From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (qmail 8482 invoked by alias); 25 Jan 2011 19:06:17 -0000 Received: (qmail 8431 invoked by uid 22791); 25 Jan 2011 19:06:16 -0000 X-SWARE-Spam-Status: No, hits=-2.9 required=5.0 tests=ALL_TRUSTED,AWL,BAYES_00 X-Spam-Check-By: sourceware.org Received: from localhost (HELO gcc.gnu.org) (127.0.0.1) by sourceware.org (qpsmtpd/0.43rc1) with ESMTP; Tue, 25 Jan 2011 19:06:08 +0000 From: "dominiq at lps dot ens.fr" To: gcc-bugs@gcc.gnu.org Subject: [Bug lto/44334] rnflow.f90 ~27% slower with -fwhole-program -flto after revision 159852 X-Bugzilla-Reason: CC X-Bugzilla-Type: changed X-Bugzilla-Watch-Reason: None X-Bugzilla-Product: gcc X-Bugzilla-Component: lto X-Bugzilla-Keywords: X-Bugzilla-Severity: normal X-Bugzilla-Who: dominiq at lps dot ens.fr X-Bugzilla-Status: WAITING X-Bugzilla-Priority: P3 X-Bugzilla-Assigned-To: unassigned at gcc dot gnu.org X-Bugzilla-Target-Milestone: --- X-Bugzilla-Changed-Fields: Message-ID: In-Reply-To: References: X-Bugzilla-URL: http://gcc.gnu.org/bugzilla/ Auto-Submitted: auto-generated Content-Type: text/plain; charset="UTF-8" MIME-Version: 1.0 Date: Tue, 25 Jan 2011 19:40:00 -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 X-SW-Source: 2011-01/txt/msg02706.txt.bz2 http://gcc.gnu.org/bugzilla/show_bug.cgi?id=44334 --- Comment #47 from Dominique d'Humieres 2011-01-25 19:06:04 UTC --- > I sorted out increasing large function growth ratio as most safe way > to deal with (easier half of) this problem. Unlike the parameters for > inline limits it won't cause code size issues. It just allow somewhat > bigger functions and thus stress more the backend on its linearity. Well, the choice is not '-finline-limit' versus '--param large-function-growth': some polyhedron tests are sensitive to some value of '-finline-limit' (ac, channel, fatigue, ...) and for most of them '--param large-function-growth' does not change anything. fatigue is quite peculiar in that there is a big speed-up with -fwhole-program for -finline-limit>=322and an additional small speed-up for --param large-function-growth>=132. In addition the later prevent a bad choice with -flto (this should probably be discussed in pr 45810 and this pr closed as fixed). Note that I am not interested by fine tuning, but to find some acceptable values of the default parameters that give good results for all (most;-) fortran codes).