https://gcc.gnu.org/bugzilla/show_bug.cgi?id=99621
--- Comment #23 from Jakub Jelinek <jakub at gcc dot gnu.org> --- Which is why I was talking about excess precision, depending on the optimizations if something needs to be spilled from the FPU stack where it is computed in 80-bit precision to stack where the spilling then rounds it to double precision. With -fexcess-precision=standard one gets the excess precision predictably everywhere, with -mfpmath=sse -msse2 there is no excess precision, double is supported naturally.
