From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id ; Fri, 24 May 2002 13:55:28 -0400 Received: (majordomo@vger.kernel.org) by vger.kernel.org id ; Fri, 24 May 2002 13:55:27 -0400 Received: from gateway-1237.mvista.com ([12.44.186.158]:18173 "EHLO hermes.mvista.com") by vger.kernel.org with ESMTP id ; Fri, 24 May 2002 13:55:26 -0400 Subject: Re: Compiling 2.2.19 with -O3 flag From: Robert Love To: Christoph Hellwig Cc: Marcus Meissner , linux-kernel@vger.kernel.org In-Reply-To: <20020524184402.A24780@infradead.org> Content-Type: text/plain Content-Transfer-Encoding: 7bit X-Mailer: Ximian Evolution 1.0.3 (1.0.3-6) Date: 24 May 2002 10:55:20 -0700 Message-Id: <1022262920.956.258.camel@sinai> Mime-Version: 1.0 Sender: linux-kernel-owner@vger.kernel.org X-Mailing-List: linux-kernel@vger.kernel.org On Fri, 2002-05-24 at 10:44, Christoph Hellwig wrote: > -Os implies -O2 + additional size-reducing features: > > [hch@sb hch]$ grep -r optimize_size /work/people/hch/gcc/gcc | wc -l > 250 > [hch@sb hch]$ > > A bunch of matches are in ChangeLog and most are target-specific, > but I guess you got the point.. I know this...maybe I am not being clear. I realize -Os is a derivate of -O2, but is it not an interesting note if -Os can be as fast (or faster) than -O2 and still generate smaller binaries? That is my point. If -Os is equivalent in speed to -O2 but also generates smaller objects, then why have -O2? If it does not generate smaller objects (which is what my testing has shown) then it is worthless. Unless it is faster than -O2, like Alan said, in which case then the two options need to rethink themselves ;-) Robert Love