Support the following intrinsics:
  _mm_cvtph_ps, _mm256_cvtph_ps, _mm_cvtps_ph, _mm256_cvtps_ph

rdar://12407875


git-svn-id: https://llvm.org/svn/llvm-project/cfe/trunk@165685 91177308-0d34-0410-b5e6-96231b3b80d8