Niche optimizations are trivial to automate in modern C++ if you wish. Many code bases automagically generate them.
The caveat is that niche optimizations are not perfectly portable, they can have edge cases. Strict portability is likely why the C++ standard makes niche optimization optional.
The caveat is that niche optimizations are not perfectly portable, they can have edge cases. Strict portability is likely why the C++ standard makes niche optimization optional.