https://gcc.gnu.org/bugzilla/show_bug.cgi?id=85957
--- Comment #17 from Rich Felker <bugdal at aerifal dot cx> ---
And indeed you're right that GCC does it wrong. This can be seen from a minimal
example:
double g(),h();
double f()
{
return g()+h();
}
where gcc emits fstpl/fldp around the second call rather than fstpt/fldt.
So this is all even more broken that I thought. It looks like the only way to
get deterministic behavior from GCC right now is to get the wrong deterministic
behavior via -ffloat-store.
Note that libfirm/cparser gets the right result, emitting fstpt/fldt.
