From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (qmail 7007 invoked by alias); 30 Apr 2004 16:59:57 -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 7000 invoked from network); 30 Apr 2004 16:59:56 -0000 Received: from unknown (HELO mail.codesourcery.com) (65.74.133.5) by sources.redhat.com with SMTP; 30 Apr 2004 16:59:56 -0000 Received: (qmail 22038 invoked from network); 30 Apr 2004 16:59:52 -0000 Received: from taltos.codesourcery.com (zack@66.92.218.83) by mail.codesourcery.com with DES-CBC3-SHA encrypted SMTP; 30 Apr 2004 16:59:52 -0000 Received: by taltos.codesourcery.com (sSMTP sendmail emulation); Fri, 30 Apr 2004 09:59:51 -0700 To: "Dave Korn" Cc: "'gcc_mailing_list'" Subject: Re: optimization issue about -O2 and -Os References: From: Zack Weinberg Date: Fri, 30 Apr 2004 19:12:00 -0000 In-Reply-To: (Dave Korn's message of "Fri, 30 Apr 2004 17:24:45 +0100") Message-ID: <87y8odiepk.fsf@egil.codesourcery.com> User-Agent: Gnus/5.110002 (No Gnus v0.2) Emacs/21.3 (gnu/linux) MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii X-SW-Source: 2004-04/txt/msg01461.txt.bz2 "Dave Korn" writes: > > Ah, I stand corrected. Would it be accurate to say that they are _both_ > shorthand for a set of -f options _and_ _also_ control a set of other > behaviours, which entail enabling, disabling, or fine-tuning the parameters > of other optimisations that do not correspond directly to -f options ? Yeah, that's pretty accurate. You can look through the source code for instances of the global flags "optimize" and "optimize_size". Anything you can do to improve the documentation in this regard would be much appreciated. It would probably be a good move to deemphasize all those -f switches; they tend not to be all that useful; I consider their primary purpose to be working around bugs in specific optimizations, using -On -fno-. zw