From owner-freebsd-hackers Sat Apr 8 14:18:50 2000 Delivered-To: freebsd-hackers@freebsd.org Received: from freefall.freebsd.org (freefall.FreeBSD.ORG [204.216.27.21]) by hub.freebsd.org (Postfix) with ESMTP id CE62937B7AC; Sat, 8 Apr 2000 14:18:48 -0700 (PDT) (envelope-from kris@FreeBSD.org) Received: from localhost (kris@localhost) by freefall.freebsd.org (8.9.3/8.9.2) with ESMTP id OAA74181; Sat, 8 Apr 2000 14:18:48 -0700 (PDT) (envelope-from kris@FreeBSD.org) X-Authentication-Warning: freefall.freebsd.org: kris owned process doing -bs Date: Sat, 8 Apr 2000 14:18:47 -0700 (PDT) From: Kris Kennaway To: "Alexey N. Dokuchaev" Cc: freebsd-hackers@freebsd.org Subject: Re: What are the best gcc optimization options for Pentium 200 MMX In-Reply-To: Message-ID: MIME-Version: 1.0 Content-Type: TEXT/PLAIN; charset=US-ASCII Sender: owner-freebsd-hackers@FreeBSD.ORG Precedence: bulk X-Loop: FreeBSD.ORG On Sat, 8 Apr 2000, Alexey N. Dokuchaev wrote: > AFAIK, Linux Mandrake has it's kernel and userland highly optimized for > Pentium architecture. However, they have additional gcc optimization > flags turned on by default, including -O3 and -mfast_math. Can you say "gimmick"? :-) gcc often produces demonstrably broken code for optimisation levels higher than -O. Probably the only useful and safe option apart from -O is the -march=pentium/pentiumpro/pentiumii/etc option for using processor-specific opcodes and instruction scheduling. By all means, compile your own system the way you want, but be sure to recompile with nothing but -O before submitting any bug reports. Kris ---- In God we Trust -- all others must submit an X.509 certificate. -- Charles Forsythe To Unsubscribe: send mail to majordomo@FreeBSD.org with "unsubscribe freebsd-hackers" in the body of the message