On Aug 23, 2005, at 9:53 AM, Richard Henderson wrote:
On Tue, Aug 23, 2005 at 09:28:50AM -0600, Roger Sayle wrote:
Good catch. This is indeed a -ffast-math (or more precisely a
flag_unsafe_math_optimizations) transformation. I'd prefer to
keep these transformations with -ffast-math, as Jan described them
as significantly helping SPEC's mesa when they were added.
Are you sure it was "(float)floor(d)"->"floorf((float)d)" that
helped mesa and not "(float)floor((double)f)"->"floorf(f)" ?
All the floor calls in mesa seem to be of the form (int)floor((double)f)
or (f - floor((double)f)). (the casts to double are implicit,
actually.)
It wouldn't bother me if the first transformation went away
even for -ffast-math. It seems egregeously wrong.
I think I'd prefer this, given that it is not useful in mesa. Will put
together a patch.
