pcmpxstrx is a lot more powerful than rep cmps.
I'm lukewarm on pcmpxstrx too, but for a different reason: I'd prefer the effort to go into more general purpose, highly flexible SIMD instructions (which is thankfully happening now with AVX 512).
I'm lukewarm on pcmpxstrx too, but for a different reason: I'd prefer the effort to go into more general purpose, highly flexible SIMD instructions (which is thankfully happening now with AVX 512).
At least the latter claims code compiled once is compatible with all possible hardware configurations, from the start (by way of giving the CPU a "remaining iterations count" and having it reply with how many it can do for the chosen vector lane shapes).
IMO, if it does end up working that well in practice, it does put all of the various incompatible versions of packed SIMD extensions in a pretty awkward spot - could we have skipped all of MMX, SSE, AVX, NEON, etc. versions with technology that has been around for almost half a century?