[Bug middle-end/78879] -fprofile-generate causes undefined reference to `____ilog2_NaN'

[coolypf at qq dot com]

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=78879

--- Comment #8 from Yuan Pengfei <coolypf at qq dot com> ---
I have sent a patch that fixes this bug. Please review it. Thanks!

https://gcc.gnu.org/ml/gcc-patches/2016-12/msg01824.html