From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (qmail 27282 invoked by alias); 3 Dec 2008 21:29:39 -0000 Received: (qmail 26900 invoked by uid 48); 3 Dec 2008 21:28:14 -0000 Date: Wed, 03 Dec 2008 21:29:00 -0000 Message-ID: <20081203212814.26899.qmail@sourceware.org> X-Bugzilla-Reason: CC References: Subject: [Bug target/38306] [4.4 Regression] 15% slowdown w.r.t. 4.3 of computational kernel on some architectures In-Reply-To: Reply-To: gcc-bugzilla@gcc.gnu.org To: gcc-bugs@gcc.gnu.org From: "hjl dot tools at gmail dot com" 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: 2008-12/txt/msg00343.txt.bz2 ------- Comment #8 from hjl dot tools at gmail dot com 2008-12-03 21:28 ------- (In reply to comment #5) > (In reply to comment #4) > > 4.3: > > -O3 -march=native -funroll-loops -ffast-math ==> 4.376 > > -O3 -march=native -funroll-loops -ffast-math -fschedule-insns ==> 3.372 > > strangely: > > http://gcc.gnu.org/onlinedocs/gcc-4.3.2/gcc/Optimize-Options.html#Optimize-Options > suggests -fschedule-insns is enabled by default at -O3 ? > This may be related to PR 37565. i386.c has void optimization_options (int level, int size ATTRIBUTE_UNUSED) { /* For -O2 and beyond, turn off -fschedule-insns by default. It tends to make the problem with not enough registers even worse. */ #ifdef INSN_SCHEDULING if (level > 1) flag_schedule_insns = 0; #endif -- http://gcc.gnu.org/bugzilla/show_bug.cgi?id=38306