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 1FyVVY-00058q-Iv for garchives@archives.gentoo.org; Thu, 06 Jul 2006 15:11:13 +0000 Received: from robin.gentoo.org (localhost [127.0.0.1]) by robin.gentoo.org (8.13.7/8.13.6) with SMTP id k66F93jq008853; Thu, 6 Jul 2006 15:09:03 GMT Received: from MIUMMR0MT03.um.ced.h3g.it ([62.13.171.111]) by robin.gentoo.org (8.13.7/8.13.6) with ESMTP id k66F4bb4009647 for ; Thu, 6 Jul 2006 15:04:37 GMT Received: from c1358217.kevquinn.com (miumgu0vp03.um.ced.h3g.it [10.216.57.163]) by MIUMMR0MT03.um.ced.h3g.it (MOS 3.5.5-GR) with ESMTP id APE36372; Thu, 6 Jul 2006 17:04:31 +0200 (CEST) Date: Thu, 6 Jul 2006 17:13:55 +0200 From: "Kevin F. Quinn" To: gentoo-dev@lists.gentoo.org Subject: Re: [gentoo-dev] Replacing cpu-feature USE flags Message-ID: <20060706171355.67c089c3@c1358217.kevquinn.com> In-Reply-To: <20060706134939.6ecd7758@snowdrop.home> References: <200607061252.33028@enterprise.flameeyes.is-a-geek.org> <20060706131905.3ba12b49@snowdrop.home> <200607061429.39803@enterprise.flameeyes.is-a-geek.org> <20060706134939.6ecd7758@snowdrop.home> X-Mailer: Sylpheed-Claws 2.3.0 (GTK+ 2.8.12; i686-pc-linux-gnu) Precedence: bulk List-Post: List-Help: List-Unsubscribe: List-Subscribe: List-Id: Gentoo Linux mail X-BeenThere: gentoo-dev@gentoo.org Reply-to: gentoo-dev@lists.gentoo.org Mime-Version: 1.0 Content-Type: multipart/signed; boundary=Sig_CmVFuqQxpH5.GJp.MDDB7sd; protocol="application/pgp-signature"; micalg=PGP-SHA1 X-Archives-Salt: 90f1448e-41e4-4a86-bd64-a5f2792f6b66 X-Archives-Hash: c32c599bed9487d6bb3980a127bc676f --Sig_CmVFuqQxpH5.GJp.MDDB7sd Content-Type: text/plain; charset=ISO-8859-1 Content-Transfer-Encoding: quoted-printable On Thu, 6 Jul 2006 13:49:39 +0100 Ciaran McCreesh wrote: > On Thu, 6 Jul 2006 14:29:39 +0200 "Diego 'Flameeyes' Petten=F2" > wrote: > | On Thursday 06 July 2006 14:19, Ciaran McCreesh wrote: > | > Sounds rather flaky and unreliable... > | Sounds rather vague and without arguments. >=20 > Well, you're assuming that a) everyone's using a C compiler, > b) that gcc has the slightest clue what it's doing, We're mostly talking about specially-written assembler code, not stuff like vectorisation or the intrinsics (which very few packages use, if any). > c) that the user has no > problem using nasty hacks to regain control, Control is easy. Specify the relevant -march in CFLAGS. > d) that this information is only needed at compile time, Where a package does run-time detection, there's no need for any conditional compilation as they build for everything anyway, so such packages wouldn't use mmx/sse/sse2 etc USE flags anyway. > e) that various gcc internal definitions won't change... Unlikely for these macros, as that would break a lot of existing code regardless what we do. > You're adding a lot of complexity, and > thus room for very weird breakages, to something that doesn't need it. I'd argue the current approach is the more complex approach, involving the user having to discover the relationship between their processor (which they've already set via -march in CFLAGS) and the various bits that their processor has. There are relatively few packages affected (<1%), so I think it's worth a try. In the end it may be that a few packages need to deal with stuff manually like with the current USE flags, but they'd be local USE flags at that point. --=20 Kevin F. Quinn --Sig_CmVFuqQxpH5.GJp.MDDB7sd Content-Type: application/pgp-signature; name=signature.asc Content-Disposition: attachment; filename=signature.asc -----BEGIN PGP SIGNATURE----- Version: GnuPG v1.4.4 (GNU/Linux) iD8DBQFErSi39G2S8dekcG0RAtkjAKCayV8Y9UU8UhO+26JOAMtIot97CwCgkZDM smILH1uYOGbcYhMLegkNATo= =fuuQ -----END PGP SIGNATURE----- --Sig_CmVFuqQxpH5.GJp.MDDB7sd-- -- gentoo-dev@gentoo.org mailing list