From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from lists.gentoo.org ([140.105.134.102] helo=robin.gentoo.org) by nuthatch.gentoo.org with esmtp (Exim 4.60) (envelope-from ) id 1GIkae-0001yc-B0 for garchives@archives.gentoo.org; Thu, 31 Aug 2006 11:20:08 +0000 Received: from robin.gentoo.org (localhost [127.0.0.1]) by robin.gentoo.org (8.13.8/8.13.6) with SMTP id k7VBHj4L009057; Thu, 31 Aug 2006 11:17:45 GMT Received: from wx-out-0506.google.com (wx-out-0506.google.com [66.249.82.235]) by robin.gentoo.org (8.13.8/8.13.6) with ESMTP id k7VBF9Nl008121 for ; Thu, 31 Aug 2006 11:15:09 GMT Received: by wx-out-0506.google.com with SMTP id r21so648794wxc for ; Thu, 31 Aug 2006 04:15:08 -0700 (PDT) DomainKey-Signature: a=rsa-sha1; q=dns; c=nofws; s=beta; d=gmail.com; h=received:message-id:date:from:sender:to:subject:in-reply-to:mime-version:content-type:content-transfer-encoding:content-disposition:references:x-google-sender-auth; b=fy5YzcL/d1RaN+XOvxS6u4zBVPif9lIadURK2a9d0bmlY/+RGEdVQ/0N0E4OGbMTQ17kBmNb+QlIIdDP6opDnMSUXtppffznYU4RpupxA5TLtTPaX7+ceG8et7pDdiKGSjerxFS9PzyGAzmKYBww9CpBJQWU+AHoHCEQDZ3MkxI= Received: by 10.70.74.1 with SMTP id w1mr329802wxa; Thu, 31 Aug 2006 04:15:08 -0700 (PDT) Received: by 10.70.110.1 with HTTP; Thu, 31 Aug 2006 04:15:08 -0700 (PDT) Message-ID: <7573e9640608310415t2cf020afr7c6bfdb752dcb728@mail.gmail.com> Date: Thu, 31 Aug 2006 04:15:08 -0700 From: "Richard Fish" Sender: richard.j.fish@gmail.com To: gentoo-user@lists.gentoo.org Subject: Re: [gentoo-user] How to properly change CFLAGS ? In-Reply-To: <1156978378.17760.22.camel@scarlatti.leonora.org> Precedence: bulk List-Post: List-Help: List-Unsubscribe: List-Subscribe: List-Id: Gentoo Linux mail X-BeenThere: gentoo-user@gentoo.org Reply-to: gentoo-user@lists.gentoo.org MIME-Version: 1.0 Content-Type: text/plain; charset=ISO-8859-1; format=flowed Content-Transfer-Encoding: 7bit Content-Disposition: inline References: <44EA1CDF.1000304@xunil.at> <20060821221616.3de2f7eb@hactar.digimed.co.uk> <44EA2532.9040606@xunil.at> <7573e9640608212006l31d2fb5dyb54d53861aad9d42@mail.gmail.com> <1156978378.17760.22.camel@scarlatti.leonora.org> X-Google-Sender-Auth: 9c57dd7451edf75a X-Archives-Salt: 71c0b61c-3eb5-41ff-8f15-465473d72fcc X-Archives-Hash: 0cf0ae25bb51f002e80036f08f2b7cdb On 8/30/06, Vladimir G. Ivanovic wrote: > On Mon, 2006-08-21 at 20:06 -0700, Richard Fish wrote: > > -Os seems to take much less time and memory to compile than -O2 or -O3. And being a > > ~arch user, time-to-compile is a nice thing to reduce. > > It is possible that one of my usual CFLAGS options (-Wall -march=k8 > -msse3 -pipe -O2 -ffast-math) overwhelms any -Os/-O2 execution time Well it looks like I'll have to retract that statement in relation to -Os/-O2. My current tests with -march=pentium4 -fweb -pipe -fomit-frame-pointer for my laptop or -march=athlon64 -fweb -pipe for my AMD box show a <5% difference in compile time between -Os and -O2. I think there was a bigger difference in previous versions of gcc, but I can't seem to find any notes or anything to support that belief... Cheers, -Richard -- gentoo-user@gentoo.org mailing list