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Re: Draft "Unsafe fp optimizations" project description.


dewar@gnat.com wrote:

> First a question: Just how useful *is* -ffast-match "now", does anyone have
> measurements to contribute. And if there are programs where it helps
> significantly, are there any analyses of why and how.

It all depends on what you mean by "now".  -ffast-math (no c :-) enables
underflow-to-zero on ia64 and alpha.  On my alpha (I've never even seen
a ia64 workstation, but they seem to exist), forcing the processor to
treat underflow-as-zero meant an 1.8 times speed up on our Numerical
Weather Forecasting system.

-- 
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
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