> This code only makes people's lives better if many languages and frameworks that translates latin-1 to utf8 are updated to have this new faster implementation.
Except CPUs evolve and what was once a fast way of doing things may no longer be very fast. And with ASM you got no compiler to generate better targeted instructions.
I've seen many instances where significant performance was gained by swapping out and old hand-written ASM routine with a plain language version.
If you ever add some optimized ASM to your code, do a performance check at startup or similar, and have the plain language version as a fallback.
I'm talking about which instructions and idioms are optimal. AFAIK, with intrinsics the compiler won't completely change what you've written.
Back in the days REP MOVSB was the fastes way to copy bytes, then Pentium came and rolling your own loop was better. Then CPUs improved and REP MOVSB was suddenly better again[1], for those CPUs. And then it changed again...
Similar story for other idioms where implementation details on CPUs change. Compilers can respond and target your exact CPU.
Except CPUs evolve and what was once a fast way of doing things may no longer be very fast. And with ASM you got no compiler to generate better targeted instructions.
I've seen many instances where significant performance was gained by swapping out and old hand-written ASM routine with a plain language version.
If you ever add some optimized ASM to your code, do a performance check at startup or similar, and have the plain language version as a fallback.