From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from pigeon.gentoo.org ([208.92.234.80] helo=lists.gentoo.org) by finch.gentoo.org with esmtp (Exim 4.60) (envelope-from ) id 1Lw5k2-0002v1-Vr for garchives@archives.gentoo.org; Tue, 21 Apr 2009 02:29:47 +0000 Received: from pigeon.gentoo.org (localhost [127.0.0.1]) by pigeon.gentoo.org (Postfix) with SMTP id 681C2E052C; Tue, 21 Apr 2009 02:29:45 +0000 (UTC) Received: from rv-out-0708.google.com (rv-out-0708.google.com [209.85.198.244]) by pigeon.gentoo.org (Postfix) with ESMTP id 368E3E052C for ; Tue, 21 Apr 2009 02:29:45 +0000 (UTC) Received: by rv-out-0708.google.com with SMTP id b17so1043268rvf.46 for ; Mon, 20 Apr 2009 19:29:44 -0700 (PDT) Precedence: bulk List-Post: List-Help: List-Unsubscribe: List-Subscribe: List-Id: Gentoo Linux mail X-BeenThere: gentoo-user@lists.gentoo.org Reply-to: gentoo-user@lists.gentoo.org MIME-Version: 1.0 Received: by 10.114.125.15 with SMTP id x15mr3666209wac.217.1240280984779; Mon, 20 Apr 2009 19:29:44 -0700 (PDT) In-Reply-To: <20090421080816.7e5c9f2f@coercion> References: <955d685d0904201720h414b7a5v72782e548e9edb85@mail.gmail.com> <20090421080816.7e5c9f2f@coercion> Date: Tue, 21 Apr 2009 12:29:44 +1000 Message-ID: <955d685d0904201929p1dd87d90jac51ce045b8375a9@mail.gmail.com> Subject: Re: [gentoo-user] gcc and -match=native From: Beau Henderson To: gentoo-user@lists.gentoo.org Content-Type: text/plain; charset=ISO-8859-1 Content-Transfer-Encoding: quoted-printable X-Archives-Salt: 7631ea52-d388-404d-878e-fd0f5516b42b X-Archives-Hash: e05f5b98c3e33dcdfe160d71d96630ab On Tue, Apr 21, 2009 at 12:08 PM, Mike Kazantsev wrote: > On Tue, 21 Apr 2009 10:20:34 +1000 > Beau Henderson wrote: > >> I was playing around with a few non-essential packages the other day >> using -march=3Dnative -v on my core2 duo ( configured with >> CHOST=3D"i686-pc-linux-gnu" ) and noticed that GCC set the -march=3Dcore= 2 >> rather than what is typically suggested on the 3rd party wiki ( which >> is to use prescott ). According to the GCC docs, the core2 option >> includes instructions for x86_64 but would this be ultimately ignored >> seeing as the CHOST is set to i686 or would these instructions bloat >> the =A0resulting binaries or could they result in conflicts of some sort >> down the line ? > > AFAIK they should be harmlessly ignored - if produced machine code will > contain them, it'll just break as soon as cpu gets down to them. > > Besides, they are useless for program which works with 32-bit registers > and data, so there should be no point to insert them anywhere in x86 > binary. > > -- > Mike Kazantsev // fraggod.net > So is GCC ignoring the fact that the systems CHOST is i686 or is this truly optimized for my situation ? --=20 Beau Dylan Henderson "No human being should be denied the fundamental right to educate themselves or indulge their curiosities. To deny any person the right to do so, for whatever reason, is nothing more than the safeguarding of ignorance to ensure that enlightenment does not become a threat. For nothing in this world is more dangerous than an open mind." -- Matthew Good