core.simd woes

[F i L]

Manu wrote:
> std.simd already does have a mammoth mess of static if(arch & 
> compiler).
> The thing about std.simd is that it's designed to be portable, 
> so it
> doesn't make sense to expose the low-level sse intrinsics 
> directly there.

Well, that's not really what I was suggesting. I was saying maybe 
eventually matching the agnostic gdc builtins in a separate 
module:

     // core.builtins

     import core.simd;

     version (GNU)
       import gcc.builtins;

     void madd(ref float4 r, float4 a, float4 b)
     {
       version (X86_OR_X64)
       {
         version (DigitalMars)
         {
           r = __simd(XMM.PMADDWD, a, b);
         }
         else version (GNU)
         {
           __builtin_ia32_fmaddpd(r, a, b)
         }
       }
     }

then std.simd can just use a single function (madd) and forget 
about all the compiler-specific switches. This may be more work 
than it's worth and std.simd should just contain all the platform 
specific switches... idk, i'm just throwing out ideas.