https://gcc.gnu.org/bugzilla/show_bug.cgi?id=71842
--- Comment #2 from joseph at codesourcery dot com <joseph at codesourcery dot
com> ---
On Mon, 11 Jul 2016, glisse at gcc dot gnu.org wrote:
> double f(double x, double y){ return fma(x, y, 0.); }
Would require -fno-signed-zeroes to be valid to optimize to x*y.
> double g(double x, double y){ return fma(0., x, y); }
Would require -ffinite-math-only -fno-signed-zeroes to be valid to
optimize to y.
Also the cases that might overflow / underflow / involve domain errors
from infinities have issues with errno setting, though GCC currently
ignores the possibility of fma setting errno.
