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RE: Big differences on SpecFP results for gcc and icc
- From: "Menezes, Evandro" <evandro dot menezes at amd dot com>
- To: "Robert Dewar" <dewar at adacore dot com>, "Uros Bizjak" <uros at kss-loka dot si>
- Cc: gcc at gcc dot gnu dot org, "Scott Robert Ladd" <scott dot ladd at coyotegulch dot com>
- Date: Mon, 13 Jun 2005 11:27:27 -0500
- Subject: RE: Big differences on SpecFP results for gcc and icc
Robert,
> > I know that these graphs don't show the results of most aggresive
> > optimization options for gcc, but that is also the case
> with icc (only
> > -O2). However, it looks that gcc and icc are not even in the same
> > class regarding FP performance. Perhaps there is some critical
> > optimizations, that are not present in gcc?
>
> Or perhaps icc has spent much more effort in optimizing the
> spec tests specifically.
>
> > I think I'm not the only person, that finds these results rather
> > "dissapointing". As Scott is currently writing a paper on gcc's FP
> > performance, perhaps someone has an explanation, why gcc's
> results are
> > so low on Pentium4 for these tests?
>
> I suggest doing more general benchmarks than just the spec
> tests, which are rather notorious targets for targetted optimization.
I agree with you. Each HPC application tends to be unlike others, making it difficult to optimize GCC for an elusive typical FP application. Not that there isn't room for improvement though.
--
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Evandro Menezes AMD Austin, TX