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Re: P4 support question (-> FAQ?)
- To: tprince at computer dot org
- Subject: Re: P4 support question (-> FAQ?)
- From: Will Menninger <william dot l dot menninger at boeing dot com>
- Date: Tue, 29 May 2001 06:52:43 -0700 (PDT)
- Cc: gcc at gcc dot gnu dot org
Tim,
Can you reveal what compilers you are testing and when/where you might
be publishing the results? My experience is that on Pentium-III's,
Intel's C compiler (v4.x) beats gcc (2.7, 2.8, 2.95) by 10%-40% margins
(largely double precision floating point codes). But I also have a
finite element field-solving C++ code where gcc beats Intel and MS VC by
more than a factor of two. I have noticed that the Intel compiler seems
to do a better job of aligning local variables on the stack to optimize
performance (the P-III apparently likes 16-byte alignments(?)).
-Will
"Tim Prince" writes:
>>[...beginning of thread deleted for brevity...]
>
>I don't expect any changes in scheduling to make major differences in
>performance on P4; gcc already does quite well when P-II optimizations are
>selected. I'm in the middle of a comparison of efficiency of code
>sequences generated by various compilers; while SSE code is required in
>many situations to make the best of P4, there are situations where gcc
>generates P-II compatible code which is faster than that available from
>commercial compilers.