Date: Mon, 7 May 2001 15:53:22 -0700 From: Kris Kennaway <kris@obsecurity.org> To: Nuno Teixeira <nuno.mailinglists@pt-quorum.com> Cc: freebsd-stable@FreeBSD.ORG Subject: Re: CFLAGS Optimization Message-ID: <20010507155322.A69703@xor.obsecurity.org> In-Reply-To: <20010507230417.F508-100000@gateway.bogus>; from nuno.mailinglists@pt-quorum.com on Mon, May 07, 2001 at 11:36:31PM %2B0100 References: <20010507230417.F508-100000@gateway.bogus>
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--XsQoSWH+UP9D9v3l Content-Type: text/plain; charset=us-ascii Content-Disposition: inline Content-Transfer-Encoding: quoted-printable On Mon, May 07, 2001 at 11:36:31PM +0100, Nuno Teixeira wrote: > Hello to all, >=20 > I came from Linux and at that time I used CFLAGS to optimize general > programs and linux kernel. >=20 > For example: >=20 > [i686]: > CFLAGS=3D'-O9 -funroll-loops -ffast-math -malign-double -mcpu=3Dpentiumpro > -march=3Dpentiumpro -fomit-frame-pointer -fno-exceptions' This ridiculous level of optimization *will* give you problems (BTW, what exactly do you think -O9 is supposed to do in gcc? Nothing more than -O3, I think you'll find). You can only safely use this kind of optimization in individual programs which you have tested continue to work when compiled that way; gcc is just too broken for this to work in general. For a general compiler setting, -O is the most you should go if you don't want your binaries to break; the FreeBSD mailing lists are full of documented cases where this has been demonstrated. > Can I use CFLAGS on FreeBSD too? If I put the CFLAGS on > /etc/defaults/make.conf, the kernel is affected by it? > Does CFLAGS can optimize programs and kernel on FreeBSD OS? It's all documented in /etc/defaults/make.conf -- come back if you still have questions. Kris --XsQoSWH+UP9D9v3l Content-Type: application/pgp-signature Content-Disposition: inline -----BEGIN PGP SIGNATURE----- Version: GnuPG v1.0.5 (FreeBSD) Comment: For info see http://www.gnupg.org iD8DBQE69ydhWry0BWjoQKURAr3OAKCHEWDH5tleDQ+uA1MVuUtTbMQE+ACeKRZT tprrfK+dCICqjp+ZmZE1EbA= =A8qw -----END PGP SIGNATURE----- --XsQoSWH+UP9D9v3l-- To Unsubscribe: send mail to majordomo@FreeBSD.org with "unsubscribe freebsd-stable" in the body of the message
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