optimization request: (-a)*(-b) => a*b

[N8TM@aol.com]

In a message dated 3/4/99 2:48:36 AM Pacific Standard Time,
Sylvain.Pion@sophia.inria.fr writes:

<< I also think the following kind of tests can be optimized:
 (-a)>0  => a<0 >>
Many compilers lump such transformations in to their equivalent of gnu's
option -ffast-math.  The transformation is valid if we exclude the behavior of
NaN values.  I have avoided using such options because of the occasional bad
effects, and because I have never been able to measure a performance
improvement on this account.