Polyhedron tests on Intel Darwin8/9

[Tim Prince]

Dorit Nuzman wrote:
>> Janne Blomqvist wrote:

>>> Now, I suppose one could argue that Fortran != IEEE 754, and that
>>> Fortran allows mathematically equivalent transformations, so by default
>>> gfortran should be a little bit looser than gcc (not as loose as
>>> everything in -ffast-math though). However, there has been discussion
>>> about FP optimization in gcc in general, so perhaps gfortran should
> wait
>>> for some kind of consensus there before doing any drastic changes. See
>>>
>>> http://gcc.gnu.org/wiki/FP_BOF
>>>
>>> http://gcc.gnu.org/wiki/GeertBosch
>>>
>>> http://gcc.gnu.org/wiki/Math_Optimization_Flags
>>>
>> One of those URLs asks about dot product optimization, but doesn't
>> mention that it happens now for sse vectorized platforms only under
>> -mfpmath=sse -ffast-math.  There was an announcement of a flag which
>> would enable this outside of -ffast-math, but I couldn't find any
>> evidence of implementation.
> 
> maybe you mean -fassociative-math. The vectorizer now relies on
> -fassociative-math instead of -ffast-math when considering vectorization of
> fp reduction.
> 
Yes, I see that -fassociative-math is working to promote vectorization,
at least for gcc-4.3  snapshots in the last month.  I'd still like to be
assured that it does not involve needless violation of parentheses.
Thanks.