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

[jakub at gcc dot gnu.org]

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

--- Comment #9 from Jakub Jelinek <jakub at gcc dot gnu.org> ---
(In reply to Sanjay Patel from comment #8)
> 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.

That is because one kind of these intrinsics originates from AMD (support for
AMD BMI is what went into GCC first) and the other from ICC which chose to
provide different names.  So, for backwards compatibility we need both sets.