From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (qmail 7126 invoked by alias); 9 Aug 2010 14:58:48 -0000 Received: (qmail 7110 invoked by uid 22791); 9 Aug 2010 14:58:46 -0000 X-SWARE-Spam-Status: No, hits=-1.4 required=5.0 tests=AWL,BAYES_00,T_RP_MATCHES_RCVD X-Spam-Check-By: sourceware.org Received: from ausxippc101.us.dell.com (HELO ausxippc101.us.dell.com) (143.166.85.207) by sourceware.org (qpsmtpd/0.43rc1) with ESMTP; Mon, 09 Aug 2010 14:58:09 +0000 X-Loopcount0: from 10.152.240.141 Subject: Re: The speed of the compiler, was: Re: Combine four insns Mime-Version: 1.0 (Apple Message framework v1081) Content-Type: text/plain; charset=us-ascii From: Paul Koning In-Reply-To: <4C601691.1000303@moene.org> Date: Mon, 09 Aug 2010 15:00:00 -0000 Cc: gcc-patches Content-Transfer-Encoding: quoted-printable Message-Id: <51F8745A-F66E-4653-B701-0A343695A8EC@dell.com> References: <4C5C20D0.5020105@codesourcery.com> <4C5C8F7C.6010509@codesourcery.com> <201008071010.53419.ebotcazou@adacore.com> <4C5FEF18.7010504@codesourcery.com> <4C6011F7.5040904@moene.org> <4C601691.1000303@moene.org> To: Toon Moene Mailing-List: contact gcc-patches-help@gcc.gnu.org; run by ezmlm Precedence: bulk List-Id: List-Archive: List-Post: List-Help: Sender: gcc-patches-owner@gcc.gnu.org X-SW-Source: 2010-08/txt/msg00675.txt.bz2 >> ... >=20 > OK, lets get serious then on the (improvement of) the speed of compilatio= n. >=20 > By far the most examples I have seen over the last decade, speed of compi= lation is a concern when developers are in the compile->fix bug->compile cy= cle. >=20 > Most of these "compiles" are -O0 -g compiles, for obvious reasons (why sp= end time on optimization when you don't even know the code is correct ?) Actually, I tend to use -O1 for debug compiles, for two reasons. (1) a numb= er of useful gcc warnings don't appear unless optimization is used; (2) if = I have to step instructions it's a whole lot more efficient. paul