https://gcc.gnu.org/bugzilla/show_bug.cgi?id=115374
--- Comment #10 from Mario Hros <k3x-devel at outlook dot com> --- That _.265t.optimized posted matches my observation. So the call into glibc fmod() is made to set errno eventually, ok. But shouldn't the returned value from the glibc call be used instead of returning NaN? I am not the one to decide. If that works as expected, then it is not a bug and this issue can be closed.
