From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (qmail 15461 invoked by alias); 8 Sep 2011 08:47:57 -0000 Received: (qmail 15447 invoked by uid 22791); 8 Sep 2011 08:47:54 -0000 X-SWARE-Spam-Status: No, hits=-2.2 required=5.0 tests=AWL,BAYES_00,RP_MATCHES_RCVD,TW_AV X-Spam-Check-By: sourceware.org Received: from sunsite.ms.mff.cuni.cz (HELO sunsite.mff.cuni.cz) (195.113.15.26) by sourceware.org (qpsmtpd/0.43rc1) with ESMTP; Thu, 08 Sep 2011 08:47:41 +0000 Received: from sunsite.mff.cuni.cz (localhost [127.0.0.1]) by sunsite.mff.cuni.cz (8.14.5/8.14.5) with ESMTP id p888ldv6001410; Thu, 8 Sep 2011 10:47:39 +0200 Received: (from jj@localhost) by sunsite.mff.cuni.cz (8.14.5/8.14.5/Submit) id p888lcMx001409; Thu, 8 Sep 2011 10:47:38 +0200 Date: Thu, 08 Sep 2011 08:47:00 -0000 From: Jakub Jelinek To: Vladimir Makarov Cc: "gcc.gcc.gnu.org" Subject: Re: Comparison of GCC-4.6.1 and LLVM-2.9 on x86/x86-64 targets Message-ID: <20110908084738.GN27949@sunsite.ms.mff.cuni.cz> Reply-To: Jakub Jelinek References: <4E678A9B.3040303@redhat.com> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <4E678A9B.3040303@redhat.com> User-Agent: Mutt/1.5.21 (2010-09-15) Mailing-List: contact gcc-help@gcc.gnu.org; run by ezmlm Precedence: bulk List-Id: List-Archive: List-Post: List-Help: Sender: gcc-owner@gcc.gnu.org X-SW-Source: 2011-09/txt/msg00058.txt.bz2 On Wed, Sep 07, 2011 at 11:15:39AM -0400, Vladimir Makarov wrote: > This year I used -Ofast -flto -fwhole-program instead of > -O3 for GCC and -O3 -ffast-math for LLVM for comparison of peak > performance. I could improve GCC performance even more by using > other GCC possibilities (like support of AVX insns, Graphite optimizations > and even some experimental stuff like LIPO) but I wanted to give LLVM > some chances too. Probably an experienced user in LLVM could improve > LLVM performance too. So I think it is a fair comparison. -march=native in addition would be nice to see, that can make significant difference, especially on AVX capable CPUs. I guess LLVM equivalent would be -march=corei7 -mtune=corei7 and, if it works, -mavx too (though, the only time I've tried LLVM 2.9 it crashed on almost anything with -mavx). Jakub