How about implementing SPMD on SIMD for D?

[solidstate1991]

I think fixing the SIMD support would be also great.

1) Make it compatible with Intel intrinsics.

2) Update it to work with AVX-512.

3) Add some preliminary support for ARM Neon.

4) Optional: Make SIMD to compile for all 32 bit targets, so I 
don't have to write long-ass assembly code for stuff. Once I even 
broke LDC with my code (see CPUblit).