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 <gentoo-user+bounces-131722-garchives=archives.gentoo.org@lists.gentoo.org>) id 1RV745-0006vf-GC for garchives@archives.gentoo.org; Mon, 28 Nov 2011 19:40:33 +0000 Received: from pigeon.gentoo.org (localhost [127.0.0.1]) by pigeon.gentoo.org (Postfix) with SMTP id BAB9021C226; Mon, 28 Nov 2011 19:40:13 +0000 (UTC) Received: from out3.smtp.messagingengine.com (out3.smtp.messagingengine.com [66.111.4.27]) by pigeon.gentoo.org (Postfix) with ESMTP id EB1F721C063 for <gentoo-user@lists.gentoo.org>; Mon, 28 Nov 2011 19:38:13 +0000 (UTC) Received: from compute6.internal (compute6.nyi.mail.srv.osa [10.202.2.46]) by gateway1.nyi.mail.srv.osa (Postfix) with ESMTP id A3F50204F1 for <gentoo-user@lists.gentoo.org>; Mon, 28 Nov 2011 14:38:13 -0500 (EST) Received: from frontend2.nyi.mail.srv.osa ([10.202.2.161]) by compute6.internal (MEProxy); Mon, 28 Nov 2011 14:38:13 -0500 DKIM-Signature: v=1; a=rsa-sha1; c=relaxed/relaxed; d=binarywings.net; h=message-id:date:from:mime-version:to:subject:references :in-reply-to:content-type; s=mesmtp; bh=FZHLAGGQ59wIGCxuqVxSW6xT oAM=; b=oHjf+2Pe/bF6cbAeLkogOTe80PeY9OGfmf9pnf2BErSxVq8p69JpYHcg hWOsmZ1MMNH6ibfD0pmh9pJUBdUekgitfeb/6ZhqGZVyq9CYKf0KSTnMgimV+pUV BUP2xn+nE/QHae3KKeoVFaZiOzjhIlC4sQuhPYyCsOCdVDjSXXk= DKIM-Signature: v=1; a=rsa-sha1; c=relaxed/relaxed; d= messagingengine.com; h=message-id:date:from:mime-version:to :subject:references:in-reply-to:content-type; s=smtpout; bh=FZHL AGGQ59wIGCxuqVxSW6xToAM=; b=N+r3q+tjSddqiZkv8Q5NNVhfUZYmK0k+lvsK x/xcQdCiwN4Fku6bpvsv3MdbilVZEbCaboiH0wnpnbzO8CZPjd9bkcWP89keaO1l cP/gZLP6cmXQJjuWL8BZxmjXaYaI+R0N3K6qrhlS7eU9JweBNOGqkzGC0pdcrcGS keemqQ8= X-Sasl-enc: fRRBX0x4WgPvZ0O8DiBW9l9pK2cpCNqQIaPwW9tRkyqX 1322509090 Received: from [192.168.5.18] (serv.binarywings.net [83.169.5.6]) by mail.messagingengine.com (Postfix) with ESMTPSA id 45BEC482534 for <gentoo-user@lists.gentoo.org>; Mon, 28 Nov 2011 14:38:07 -0500 (EST) Message-ID: <4ED3E30C.8060302@binarywings.net> Date: Mon, 28 Nov 2011 20:37:48 +0100 From: Florian Philipp <lists@binarywings.net> User-Agent: Mozilla/5.0 (X11; Linux x86_64; rv:7.0.1) Gecko/20111031 Thunderbird/7.0.1 Precedence: bulk List-Post: <mailto:gentoo-user@lists.gentoo.org> List-Help: <mailto:gentoo-user+help@lists.gentoo.org> List-Unsubscribe: <mailto:gentoo-user+unsubscribe@lists.gentoo.org> List-Subscribe: <mailto:gentoo-user+subscribe@lists.gentoo.org> List-Id: Gentoo Linux mail <gentoo-user.gentoo.org> X-BeenThere: gentoo-user@lists.gentoo.org Reply-to: gentoo-user@lists.gentoo.org MIME-Version: 1.0 To: gentoo-user@lists.gentoo.org Subject: Re: Devs and rice flags (Was: Re: [gentoo-user] emerge -j, make -j and make -l ) References: <CA+czFiDmbKRjj28ej5zBjb41ZJ8uCLthj6vt7LKLWTa_rAerOw@mail.gmail.com> <CAA2qdGV4QzD-WJyU2rpu3t377eXt1EYgzKp3dwWVQffo0m=N7w@mail.gmail.com> <CA+czFiBKSn0k9Mux_Rq9HXCbY3iT9OcXuFczQ8ifD_UXy2yh-A@mail.gmail.com> <4ED3D954.8040904@binarywings.net> <CA+czFiBtR0i_paeJw_Co1mCDbP7boxfy0QasQWNe74cv_9xO-Q@mail.gmail.com> In-Reply-To: <CA+czFiBtR0i_paeJw_Co1mCDbP7boxfy0QasQWNe74cv_9xO-Q@mail.gmail.com> X-Enigmail-Version: 1.4a1pre Content-Type: multipart/signed; micalg=pgp-sha1; protocol="application/pgp-signature"; boundary="------------enig0602C7F3316C118B28B3EF6B" X-Archives-Salt: 6eb466c6-733e-4471-bbf5-8bb206597b8f X-Archives-Hash: 9c345967c1ff218cd951d7bf3bbfd046 This is an OpenPGP/MIME signed message (RFC 2440 and 3156) --------------enig0602C7F3316C118B28B3EF6B Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: quoted-printable Am 28.11.2011 20:14, schrieb Michael Mol: > On Mon, Nov 28, 2011 at 1:56 PM, Florian Philipp <lists@binarywings.net= > wrote: >> Am 28.11.2011 18:56, schrieb Michael Mol: >>> On Mon, Nov 28, 2011 at 11:46 AM, Pandu Poluan <pandu@poluan.info> wr= ote: >>> No, you've got some ugly flags in there. -fexcess-precision and >>> -funsafe-math-optimizations, in particular. (I must have been talking= >>> to someone else last week; sorry, I'm terrible with names.) >>> >> >> I doubt -fexcess-precision=3Dfast does anything at all. Pandu uses an >> AMD64 system, right? Then you have -mfpmath=3Dsse set per default and = SSE >> does not have excess precision issues (that's just for the old x87 FPU= ). >> Even if you used that, is redundant because of your other flags. To >> quote `man gcc`: >> "-fexcess-precision=3Dstandard is not implemented for languages other = than >> C, and has no effect if -funsafe-math-optimizations or -ffast-math is >> specified." <-- Therefore you always have ..=3Dfast anyway. >> >> -funsafe-math-optimizations is really terrible. Either you us floating= >> point arithmetic, then you have to rely on it because it is hard enoug= h >> already to gain necessary precision with it, or you don't, then you >> don't need that flag because it doesn't improve performance. >=20 > I didn't know (or forgot) what arch he was using. >=20 >>> -fomit-frame-pointer shouldn't cause any headaches unless you're >>> feeding a gdb stack trace, and you're not adding any debugging data, >>> so your stack traces would be pretty useless, anyway. >>> >> >> If you are on an AMD64 system, this flag is implied because it doesn't= >> affect stack traces on x86_64 anymore. >=20 > AMD64 puts the requisite data in its own register, right? >=20 I guess so. Never actually looked up how stack traces are produced. I just reproduced what `man gcc` tells me :) > Yeah, it sounds like Pandu's setup CFLAGS can use some cleanup. >=20 I wonder how many CPU cycles you save by reducing the number of parameters emerge has to pass to gcc. ;) >>> I don't know about -floop-interchange, -floop-strip-mine or >>> -floop-block. I recognize at least one of them from the discussion of= >>> graphite the other day. >>> >> >> These definitely need graphite to have any effect. Then they should be= >> reasonably safe (as far as anything relying on experimental compiler >> frameworks can be considered safe). >=20 > Upstream devs might take issue with them, but I'm still not sure they > should affect bug reports of build-time failures. I would *hope* > upstream gcc is doing tests on its own build tools compiled with its > graphite optimizations. I don't know about make and autotools, though. >=20 Agreed. Even if upstream for failing package doesn't want to handle it, you can still redirect it to the gcc folks. Even a bug report flagged WONTFIX or INVALID is helpful for the next user who stumbles upon weird compile issues. Regards, Florian Philipp --------------enig0602C7F3316C118B28B3EF6B Content-Type: application/pgp-signature; name="signature.asc" Content-Description: OpenPGP digital signature Content-Disposition: attachment; filename="signature.asc" -----BEGIN PGP SIGNATURE----- Version: GnuPG v2.0.17 (GNU/Linux) Comment: Using GnuPG with Mozilla - http://enigmail.mozdev.org/ iEYEARECAAYFAk7T4xEACgkQqs4uOUlOuU8cnwCfeI4k4Txwn5yBR8pvW3mhL8tM 8eUAn3zugXRl3tgFCn+e90oMdWijxI8S =qfbV -----END PGP SIGNATURE----- --------------enig0602C7F3316C118B28B3EF6B--