From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (qmail 32134 invoked by alias); 6 May 2010 14:24:11 -0000 Received: (qmail 32125 invoked by uid 22791); 6 May 2010 14:24:10 -0000 X-SWARE-Spam-Status: No, hits=-5.9 required=5.0 tests=AWL,BAYES_00,RCVD_IN_DNSWL_HI,T_RP_MATCHES_RCVD X-Spam-Check-By: sourceware.org Received: from cantor.suse.de (HELO mx1.suse.de) (195.135.220.2) by sourceware.org (qpsmtpd/0.43rc1) with ESMTP; Thu, 06 May 2010 14:24:06 +0000 Received: from relay1.suse.de (charybdis-ext.suse.de [195.135.221.2]) (using TLSv1 with cipher DHE-RSA-AES256-SHA (256/256 bits)) (No client certificate requested) by mx1.suse.de (Postfix) with ESMTP id 053A88D893 for ; Thu, 6 May 2010 16:24:04 +0200 (CEST) Date: Thu, 06 May 2010 14:24:00 -0000 From: Richard Guenther To: gcc@gcc.gnu.org Subject: [RFC] Introduce -Ofast Message-ID: User-Agent: Alpine 2.00 (LNX 1167 2008-08-23) MIME-Version: 1.0 Content-Type: TEXT/PLAIN; charset=US-ASCII 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: 2010-05/txt/msg00099.txt.bz2 This is a proposal to introduce an optimization level -Ofast that can collect (target specific) optimization flags that can affect runtime behavior such as -funsafe-math-optimizations or -mrecip. Currently none of the standard optimization levels have this kind of affect and we should not change that (people might argue that -funsafe-math-optimizations can go into -O3). For floating-point intensive programs people often disregard the various special (and target dependent) flags and/or do not know about -ffast-math. -Ofast on the other hand is recognized by many compilers and is widely known to affect program behavior in corner cases. I would initially propose to make -Ofast be -O3 -ffast-math and would strongly encourage target maintainers that consider adding to -Ofast make sure that popular benchmarks for their target still behave correctly when using -Ofast. Any comments or objections? After the discussion has died down I will propose a patch to gcc-patches. Thanks, Richard.