From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (qmail 15781 invoked by alias); 26 Mar 2003 21:16:00 -0000 Mailing-List: contact gcc-prs-help@gcc.gnu.org; run by ezmlm Precedence: bulk List-Archive: List-Post: List-Help: Sender: gcc-prs-owner@gcc.gnu.org Received: (qmail 15764 invoked by uid 71); 26 Mar 2003 21:16:00 -0000 Date: Wed, 26 Mar 2003 21:27:00 -0000 Message-ID: <20030326211600.15763.qmail@sources.redhat.com> To: nobody@gcc.gnu.org Cc: gcc-prs@gcc.gnu.org, From: Alexander Leidinger Subject: Re: optimization/10189: pentium4 breaks suns libm code for __ieee754_pow(double x, double y) Reply-To: Alexander Leidinger X-SW-Source: 2003-03/txt/msg01837.txt.bz2 List-Id: The following reply was made to PR optimization/10189; it has been noted by GNATS. From: Alexander Leidinger To: gcc-gnats@gcc.gnu.org Cc: ljrittle@gcc.gnu.org, freebsd-current@freebsd.org, gcc-bugs@gcc.gnu.org, gcc-prs@gcc.gnu.org, nobody@gcc.gnu.org, till@f111.hadiko.de Subject: Re: optimization/10189: pentium4 breaks suns libm code for __ieee754_pow(double x, double y) Date: Wed, 26 Mar 2003 22:09:34 +0100 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