[libcxx-commits] [libcxx] [libcxx] Use generic builtins for popcount, clz and ctz (PR #86563)

[Mark de Wever via libcxx-commits]

https://github.com/mordante commented:

Thanks for your patch. I like to only use the new builtin where it carries its weight.

Please explain in the commit message why this change is useful. 

https://github.com/llvm/llvm-project/pull/86563