Handle simd intrinsics

[jrmuizel]

For example it would be nice to be able to handle the following code:

#include <xmmintrin.h>
#include <emmintrin.h>

void
unpack_128_2x128 (__m128i data, __m128i* data_lo, __m128i* data_hi)
{
    *data_lo = _mm_unpacklo_epi8 (data, _mm_setzero_si128 ());
    *data_hi = _mm_unpackhi_epi8 (data, _mm_setzero_si128 ());
}

[rinon]

Indeed. We decided a while back to put simd support off until someone needed it. Considering simd support is in stable now, we'll take another look at translating simd types and builtins. Assuming everything matches up well enough, we should be able to add this soon.

[ahomescu]

Translating the types and builtins directly to their Rust core::arch equivalents looks like the most straightforward approach.

[TheDan64]

SIMD support has been merged as of 78372fd. The translator should now translate all of the __m* types and most of the __mm* functions (rust is missing some small subset of instructions so we can't translate those)

If you find any other SIMD functions that go untranslated, and have rust equivalents (even if not stable), please feel free to reopen this issue!