[Bug target/60847] [4.9/4.10 Regression] x86 BMI intrinsics not recognized

[spatel at rotateright dot com]

http://gcc.gnu.org/bugzilla/show_bug.cgi?id=60847

--- Comment #8 from Sanjay Patel <spatel at rotateright dot com> ---
Thanks, Jakub. 

I see that the fix duplicates all of the intrinsics with a
double-leading-underscore variant. Why do we need that? AFAIK, no other x86
intrinsics have this kind of duplication.