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Re: Activate -mrecip with -ffast-math?
- From: Uros Bizjak <ubizjak at gmail dot com>
- To: GCC <gcc at gcc dot gnu dot org>
- Cc: Giovanni Bajo <rasky at develer dot com>, Bradley Lucier <lucier at math dot purdue dot edu>, Roger Sayle <roger at eyesopen dot com>
- Date: Sun, 17 Jun 2007 20:20:36 +0200
- Subject: Re: Activate -mrecip with -ffast-math?
Hello!
I was wondering if there are objects to automatically activating Uros'
new -mrecip flag when -ffast-math is specified. It looks like a good
match since -mrecip is exactly about fast non-precise mathematics.
There is a discussion in gcc-patches@ mailing list about this topic, in
"Re: [PATCH, middle-end, i386]: reciprocal rsqrt pass + full recip x86
backend support" thread [1]. The main problem is, that one of the
polyhedron tests segfaults with this patch (not the problem of the recip
patch, but usage of questionable FP equivalence tests and FP indexes in
the array).
Uros.
[1]: http://gcc.gnu.org/ml/gcc-patches/2007-06/msg01146.html