[i386] Replace builtins with vector extensions

[Marc Glisse]

On Sun, 7 Apr 2013, Marc Glisse wrote:

>  extern __inline __m128i __attribute__((__gnu_inline__, __always_inline__,
> __artificial__))
>  _mm_slli_epi16 (__m128i __A, int __B)
>  {
> -  return (__m128i)__builtin_ia32_psllwi128 ((__v8hi)__A, __B);
> +  return (__m128i) ((__v8hi)__A << __B);
>  }

Actually, I believe I have to keep using the builtins for shifts, because 
the intrinsics have well defined behavior for large __B whereas << and >> 
don't.

-- 
Marc Glisse