From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (qmail 18194 invoked by alias); 25 Jun 2005 00:06:17 -0000 Mailing-List: contact gcc-help@gcc.gnu.org; run by ezmlm Precedence: bulk List-Archive: List-Post: List-Help: Sender: gcc-owner@gcc.gnu.org Received: (qmail 18183 invoked by uid 22791); 25 Jun 2005 00:06:14 -0000 Received: from x93.infopact.nl (HELO x93.infopact.nl) (212.29.160.93) by sourceware.org (qpsmtpd/0.30-dev) with ESMTP; Sat, 25 Jun 2005 00:06:14 +0000 Received: from 63-66-dsl.ipact.nl (63-66-dsl.ipact.nl [84.35.66.63]) by x93.infopact.nl (8.12.10/8.12.10) with ESMTP id j5P066Wv019171; Sat, 25 Jun 2005 02:06:06 +0200 From: Steven Bosscher To: gcc@gcc.gnu.org Subject: Re: [RFH] - Less than optimal code compiling 252.eon -O2 for x86 Date: Sat, 25 Jun 2005 00:06:00 -0000 User-Agent: KMail/1.7.1 Cc: fjahanian , Andrew Pinski References: <91fc834a41b6161b507a2a714c7b867a@physics.uc.edu> In-Reply-To: MIME-Version: 1.0 Content-Type: text/plain; charset="iso-8859-1" Content-Transfer-Encoding: 7bit Content-Disposition: inline Message-Id: <200506250206.23245.stevenb@suse.de> X-Spam-Score: undef - spam-scanning disabled X-SW-Source: 2005-06/txt/msg01029.txt.bz2 On Saturday 25 June 2005 01:48, fjahanian wrote: > On Jun 24, 2005, at 3:16 PM, Andrew Pinski wrote: > > I wonder why combine can do the simplification though which is why > > still > > produce good code for the simple testcase: > > void f1(double *d,float *f2) > > { > > *f2 = 0.0; > > *d = 0.0; > > } > > It is hard to reproduce the simple test case, exhibiting the same > problem (-O1 producing better code than -O2). Yes, small test cases > move the desired simplification to other phases. It often helps if you know what function your poorer code is in. You could e.g. try to make the .optimized dump of that function compilable and see if the problem shows up there again. Then work your way down to something small. Gr. Steven