[Bug c/82318] -fexcess-precision=standard has no effect on a libm function call

[vincent-gcc at vinc17 dot net]

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=82318

--- Comment #3 from Vincent Lefèvre <vincent-gcc at vinc17 dot net> ---
(In reply to Andrew Pinski from comment #1)
> This is interesting because log2 should have already done a rounding to
> double before returning.

I suppose that if the C library has been built with GCC without
-fexcess-precision=standard (explicitly or implied), then this rounding is not
done.

I've done my tests on a Debian/unstable machine (currently glibc 2.24).