64-bit and SSE

[bearophile]

dsimcha:
> Is SSE(2) inherently faster then (at least in real-world implementations) than
> x87, even when you don't vectorize?<

sqrt for example is fast, and there are other high level instructions (for video decoding cryptography, etc).
But you have to think how much time has passed from the design of C language. CPUs when C was designed were profoundly different from the ones available now. If D will have some success, future CPUs will be surely different from the current ones. I think SSE registers will be kind of obsolete when AVX will be out about next year. Do you need to change the ABI of D3 again for AVX?

Bye,
bearophile