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Re: gcc300 benchmarks slower than gcc295.3?
- To: gcc at gcc dot gnu dot org
- Subject: Re: gcc300 benchmarks slower than gcc295.3?
- From: "Steven G. Johnson" <stevenj at ab-initio dot mit dot edu>
- Date: Tue, 17 Jul 2001 18:48:25 -0400 (EDT)
- Reply-To: "Steven G. Johnson" <stevenj at alum dot mit dot edu>
For a simple example of a code (for single-precision, so 8-byte
alignment is not an issue) that gcc 3.0 does significantly worse on than
2.95.3, with an analysis of the assembly output, see also:
http://gcc.gnu.org/ml/gcc-bugs/2001-06/msg01553.html
We've seen regressions elsewhere as well, and I think that the
optimization flaws in gcc 3.0 are real. Hopefully, this kind of
performance bug will see a rapid improvement to at least 2.95.3 levels in
upcoming gcc releases...
Cordially,
Steven G. Johnson