Hello, this is the compiler calling back at you. I am very sorry that I cannot write efficient SIMD code but neither can you. If we can work together, we will outperform our individual selves as a team.

So you go ahead and write clever SIMD code but please use the SIMD intrinsics I can understand, not inline assembler which I cannot do anything with. You are very good in expressing algorithms in a SIMD friendly way and do a decent job in instruction selection.

You, however, are not very good in doing instruction scheduling and register allocation, so let me handle that and we can achieve a result that can keep the CPU pipelines busy. When you make the tiniest change to the program, I can re-do instruction scheduling and register allocation in an instant, when that would take you hours to rewrite the whole algorithm to use different registers.

my point: SIMD intrinsics + a smart C compiler produces a lot better code than a programmer writing assembly. Clang + vector extensions in particular is very good at it.