From owner-freebsd-alpha Thu Mar 23 11:24: 7 2000 Delivered-To: freebsd-alpha@freebsd.org Received: from duke.cs.duke.edu (duke.cs.duke.edu [152.3.140.1]) by hub.freebsd.org (Postfix) with ESMTP id 7EC2937BE11; Thu, 23 Mar 2000 11:23:54 -0800 (PST) (envelope-from gallatin@cs.duke.edu) Received: from grasshopper.cs.duke.edu (grasshopper.cs.duke.edu [152.3.145.30]) by duke.cs.duke.edu (8.9.3/8.9.3) with ESMTP id OAA06427; Thu, 23 Mar 2000 14:23:42 -0500 (EST) Received: (from gallatin@localhost) by grasshopper.cs.duke.edu (8.9.3/8.9.1) id OAA09970; Thu, 23 Mar 2000 14:23:12 -0500 (EST) (envelope-from gallatin@cs.duke.edu) From: Andrew Gallatin MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Transfer-Encoding: 7bit Date: Thu, 23 Mar 2000 14:23:12 -0500 (EST) To: Charles Cox Cc: Cy Schubert - ITSD Open Systems Group , Andrew Gallatin , obrien@FreeBSD.ORG, Howard Leadmon , freebsd-alpha@FreeBSD.ORG, freebsd-stable@FreeBSD.ORG Subject: Re: Compiler problems with -O2 (was Re: CVS Trouble, even under 4.0-RELEASE (alpha) HELP!) In-Reply-To: References: <200003231425.GAA01222@cwsys.cwsent.com> X-Mailer: VM 6.43 under 20.4 "Emerald" XEmacs Lucid Message-ID: <14554.28033.439748.801349@grasshopper.cs.duke.edu> Sender: owner-freebsd-alpha@FreeBSD.ORG Precedence: bulk X-Loop: FreeBSD.org Charles Cox writes: > I would like to add that some of us who do a lot of numerically intensive > programming, and that need to squeeze every last available cycle out of > our CPU's would really appreciate having -O2 available for userland > programs. To me, getting rid of the -O2+ switch would be like outlawing > cars because someone had a really bad car accident. Just like driving a > car, using gcc and the -O2 switch safely are the USER's > responsibility. Having said this though, I do fully support having > comments in make.conf, and documentation elsewhere that cautions against > compiling a kernel with -O2. > > CC You're missing the point almost entirely. FreeBSD's stock gcc -O2 is demonstrably __broken__ on the alpha. You cannot trust code it outputs. If you want to obtain results as quickly as possible & do not care if they are correct, it would be much faster to read them from /dev/zero. ;-) ------------------------------------------------------------------------------ Andrew Gallatin, Sr Systems Programmer http://www.cs.duke.edu/~gallatin Duke University Email: gallatin@cs.duke.edu Department of Computer Science Phone: (919) 660-6590 To Unsubscribe: send mail to majordomo@FreeBSD.org with "unsubscribe freebsd-alpha" in the body of the message