From owner-freebsd-current@FreeBSD.ORG Wed Mar 26 13:09:52 2003 Return-Path: Delivered-To: freebsd-current@freebsd.org Received: from mx1.FreeBSD.org (mx1.freebsd.org [216.136.204.125]) by hub.freebsd.org (Postfix) with ESMTP id 5B8DB37B404 for ; Wed, 26 Mar 2003 13:09:52 -0800 (PST) Received: from mailout01.sul.t-online.com (mailout01.sul.t-online.com [194.25.134.80]) by mx1.FreeBSD.org (Postfix) with ESMTP id D0DA343F75 for ; Wed, 26 Mar 2003 13:09:48 -0800 (PST) (envelope-from Alexander@Leidinger.net) Received: from fwd09.sul.t-online.de by mailout01.sul.t-online.com with smtp id 18yI9b-0008VN-04; Wed, 26 Mar 2003 22:09:47 +0100 Received: from Andro-Beta.Leidinger.net (520065502893-0001@[80.131.122.51]) by fmrl09.sul.t-online.com with esmtp id 18yI9R-1uC0KeC; Wed, 26 Mar 2003 22:09:37 +0100 Received: from Magelan.Leidinger.net (Magelan [192.168.1.1]) h2QL9ZOq067328; Wed, 26 Mar 2003 22:09:35 +0100 (CET) (envelope-from Alexander@Leidinger.net) Received: from Magelan.Leidinger.net (netchild@localhost [127.0.0.1]) by Magelan.Leidinger.net (8.12.7/8.12.7) with SMTP id h2QL9YL9003252; Wed, 26 Mar 2003 22:09:35 +0100 (CET) (envelope-from Alexander@Leidinger.net) Date: Wed, 26 Mar 2003 22:09:34 +0100 From: Alexander Leidinger To: gcc-gnats@gcc.gnu.org Message-Id: <20030326220934.398c7455.Alexander@Leidinger.net> In-Reply-To: <20030326130118.8374.qmail@sources.redhat.com> References: <20030326130118.8374.qmail@sources.redhat.com> X-Mailer: Sylpheed version 0.8.9claws (GTK+ 1.2.10; i386-portbld-freebsd5.0) Mime-Version: 1.0 Content-Type: text/plain; charset=US-ASCII Content-Transfer-Encoding: 7bit X-Sender: 520065502893-0001@t-dialin.net X-Spam-Status: No, hits=-24.9 required=5.0 tests=EMAIL_ATTRIBUTION,IN_REP_TO,QUOTED_EMAIL_TEXT, RCVD_IN_NJABL,REFERENCES,REPLY_WITH_QUOTES,X_NJABL_DIALUP autolearn=ham version=2.50 X-Spam-Level: X-Spam-Checker-Version: SpamAssassin 2.50 (1.173-2003-02-20-exp) cc: freebsd-current@freebsd.org cc: gcc-bugs@gcc.gnu.org cc: gcc-prs@gcc.gnu.org cc: nobody@gcc.gnu.org cc: ljrittle@gcc.gnu.org Subject: Re: optimization/10189: pentium4 breaks suns libm code for __ieee754_pow(double x, double y) X-BeenThere: freebsd-current@freebsd.org X-Mailman-Version: 2.1.1 Precedence: list List-Id: Discussions about the use of FreeBSD-current List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , X-List-Received-Date: Wed, 26 Mar 2003 21:09:55 -0000 On 26 Mar 2003 13:01:18 -0000 ljrittle@gcc.gnu.org wrote: > Synopsis: pentium4 breaks suns libm code for __ieee754_pow(double x, double y) [...] > FreeBSD src tree; and (c) that really cares about building FreeBSD > src with special CPU settings (do you guys really see enough speedup > to warrant this extra nightmare? ;-) Without knowing anything about the FreeBSD related PRs in the gcc PR database I just comment on the last part of the quoted sentence... The official "allowed" optimization is "-O". But it is as easy as setting 'CFLAGS=-my-special-optim' in /etc/make.conf and start "make buildworld" in /usr/src to rebuild the userland with new optimizations. And trust me, as long as gcc ships with a description of other optimizations beneath "-O" there will be (clueless or smart... does it really matter here?) people which will try those optimizations on everything (after I managed to convince the Linux version of icc to generate FreeBSD object files and committed a port into our ports collection one of the first questions was "Are we are able to build the userland/kernel with it?", and now after icc is also able to link files without the help of gcc they ask "How much does it gain us to build the userland/kernel with icc?", even if it isn't possible to use icc to build the entire (or even large parts of the) kernel/userland yet). So it isn't a matter of "does it improve things if I do it this way" or "is it possible to do it this way", it's a matter of "how many PRs does it generate when -march=pentium4 breaks something but other -march=pentiumX optimizations don't"... Thanks for your insightful mail, Alexander. -- 0 and 1. Now what could be so hard about that? http://www.Leidinger.net Alexander @ Leidinger.net GPG fingerprint = C518 BC70 E67F 143F BE91 3365 79E2 9C60 B006 3FE7