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Re: SSE2 benchmarks
- To: Jan Hubicka <jh at suse dot cz>
- Subject: Re: SSE2 benchmarks
- From: Paolo Carlini <pcarlini at unitus dot it>
- Date: Mon, 02 Jul 2001 12:04:12 +0200
- CC: gcc at gcc dot gnu dot org, tprince at computer dot org
- References: <3B3CA9C2.42FB2E9B@unitus.it> <004b01c101a6$dce6b2b0$9865fea9@timayum4srqln4> <20010702113847.C3390@atrey.karlin.mff.cuni.cz>
Hi all, hi Jan, hi Tim, and thanks for your feedback.
In the meanwhile, I have downloaded the original flops.c code and tried
compiling and running it.
If you are interested I may post the results for my PII (no SSE or SSE2,
unfortunately).
Anyway, what do you (people knowing well GCC's x86 backend) expect? I mean, in
those simple float loops how GCC is supposed to compare to other widespread
compilers?
I'm asking this because some *preliminary* results seem to indicate that VC6
(under Windoze98) is appreciably better than both 2.95.x and 3.0 ;-)
Cheers,
Paolo.
Jan Hubicka wrote:
> Hi from the vacantion :)
> > That article scoffs at loops involving branches, but it happens that the
> > gcc-3.1 -msse2 option is doing extremely well on certain cases involving
> > comparison and branches, as well as on some cases involving sum
> > reductions. More than one person has jumped into assuming that
> > gcc -msse2 includes vectorization, but up to now it uses only serial
> > sse2 instructions.
> Ineed, this is confusing. I will send the patch for docs explicitly
> mentioning that sse don't equal to autovectorization.
>
> Honza
> >