Andrew Thomas Pinski wrote:
The fact is that Roger's patch introduced a regression (this word
should be clear enough here), in that some users now have their old
code broken, and they are forced to add the -frounding-math option
(after having lost some time finding about this non trivial issue).
This is a long term hindrance.
Actually before roger's patch the default is the same. Just there was no
way to turn it off.
Actually, there are 2 things controlled by -frounding-math :
1) constant propagation of FP operations
2) generic transformations like (-a)*b <-> -(a*b)
At the time Roger's patch went in, I believe that only 2) was concerned,
and GCC did not try to do anything special about 1).
And *this*, is the "regression" I'm complaining about.
Later, 1) started to be taken care of, and it was unfortunately
added under the control of the same -frounding-math option.
Which now, makes it harder to come back, since we want different
defaults for these two aspects.
I have already mentioned in a bugzilla PR that it could be nice
to have 2 options, but IIRC, I did not get any reply to this.
--
Sylvain Pion
INRIA Sophia-Antipolis
Geometrica Project-Team
CGAL, http://cgal.org/
