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Re: GCC trunk SPEC2000 performance
- From: Jan Hubicka <jh at suse dot cz>
- To: Richard Henderson <rth at redhat dot com>,David Edelsohn <dje at watson dot ibm dot com>,Mark Mitchell <mark at codesourcery dot com>, gcc at gcc dot gnu dot org
- Date: Thu, 20 Jun 2002 20:26:13 +0200
- Subject: Re: GCC trunk SPEC2000 performance
- References: <200206200243.WAA23358@makai.watson.ibm.com> <20020620111650.B16657@redhat.com>
> On Wed, Jun 19, 2002 at 10:43:40PM -0400, David Edelsohn wrote:
> > 2) "peak" (-O3 -funroll-all-loops -fprefetch=loop-arrays) produces slower
> > code than base (-O2) for many tests.
>
> Peak cannot be considered "peak" with -funroll-all-loops
> as opposed to -funroll-loops. That forces the compiler
> to unroll a loop against its better judgement.
Yes, it is not meant to give best perofmrance, as the code is bloated
seriously. I like it to point out the code issue problems anyway.
It is nice to see that GCC generated code is getting smaller gradulary,
that was not the case with older releases.
Honza
>
> It's good for correctness testing, however.
>
>
> r~