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Re: GCC beaten by ICC in stupid trig test!
- From: Toon Moene <toon at moene dot indiv dot nluug dot nl>
- To: Roger Sayle <roger at eyesopen dot com>
- Cc: Robert Dewar <dewar at gnat dot com>, Bradley Lucier <lucier at math dot purdue dot edu>,Scott Robert Ladd <coyote at coyotegulch dot com>, gcc at gcc dot gnu dot org, gcc-patches at gcc dot gnu dot org
- Date: Thu, 25 Mar 2004 22:35:35 +0100
- Subject: Re: GCC beaten by ICC in stupid trig test!
- Organization: Moene Computational Physics, Maartensdijk, NL
- References: <Pine.LNX.4.44.0403250430380.28065-100000@www.eyesopen.com>
Roger Sayle wrote:
> Toon does numerical weather
forecasting, and he seems happy with -ffast-math.
Indeed, and perhaps the incongruous rambling on "erroneous floating
point approximations" is entirely the fault of the group that uses (and
by any theoretical analysis is allowed to use) -ffast-math (or whatever
the option might be called on a compiler from one of our competitors.
For me, it's very simple: If -ffast-math leads to answers that are less
accurate (in the verification-against-observation-sense) or unphysical
(against theoretical limit analysis), then I'll inspect my Fortran code
and repair the formulation (either a single expression or the layout of
loop code) that is responsible for the mayhem.
Under no circumstances I will give up using -ffast-math.
--
Toon Moene - mailto:toon@moene.indiv.nluug.nl - phoneto: +31 346 214290
Saturnushof 14, 3738 XG Maartensdijk, The Netherlands
Maintainer, GNU Fortran 77: http://gcc.gnu.org/onlinedocs/g77_news.html
GNU Fortran 95: http://gcc.gnu.org/fortran/ (under construction)