[PATCH] Introduce arm_acle.h supporting existing LLVM builtin intrinsics

[Reid Kleckner]

This sounds very similar to the immintrin.h etc headers that Intel
provides, which IMO are great.  We don't have to implement everything as a
builtin in the compiler.  We can insulate ourselves with a header layer.

GCC's __builtins aren't standard, so having a real document seems like a
step forward.

-- from a peanut gallery somewhere

http://reviews.llvm.org/D4296