https://gcc.gnu.org/bugzilla/show_bug.cgi?id=63780
--- Comment #2 from Jonathan Wakely <redi at gcc dot gnu.org> ---
This is nothing to do with libstdc++:
int main() {
int n;
double x = 3419, m = 360;
double y = __builtin_remainder(x, m);
double z = __builtin_remquo(x, m, &n);
__builtin_printf("result %.0f %.0f %d\n", y, z, n);
}
With optimisation GCC inlines its own definitions that give the right answer,
so this looks like a glibc bug.
