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Re: gcc/gcc config.gcc config/sparc/linux.h config ...
- From: Toon Moene <toon at moene dot indiv dot nluug dot nl>
- To: Brad Lucier <lucier at math dot purdue dot edu>
- Cc: "David S. Miller" <davem at redhat dot com>, gcc-patches at gcc dot gnu dot org
- Date: Thu, 04 Apr 2002 20:48:45 +0200
- Subject: Re: gcc/gcc config.gcc config/sparc/linux.h config ...
- Organization: Moene Computational Physics, Maartensdijk, The Netherlands
- References: <200204040151.g341pSY27434@banach.math.purdue.edu>
Brad Lucier wrote:
> Also, this is a performance increase of about a factor of 100, and it seems
> to be extremely simple and clean; should it not also be installed on the
> 3.1 branch?
Are you sure you really *want* underflow-flushed-to-zero ? [ You're one
of our (i.e., gcc testers') IEEE-conformant users - at least so I
thought ]
I got about 40 % speedup on our Numerical Weather Forecasting code [on
Alpha], but that's because underflows are (naturally) very rare in such
code (it's not impossible, given enough careful programming effort, to
eradicate them completely) ...
I noticed that this improvement (for IA-64 and Alpha) is not mentioned
yet on the gcc-3.1/changes.html page under the header "optimization
improvements"; perhaps it should be.
--
Toon Moene - mailto:toon@moene.indiv.nluug.nl - phoneto: +31 346 214290
Saturnushof 14, 3738 XG Maartensdijk, The Netherlands
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