[o11c]

No, the `least` typedefs are irrelevant aliases for the exact type these days (except supposedly some 32-bit-only DSPs exist though. But 9-bit computing has been obsolete for longer than most of us have been alive, despite talking about it).

The `fast` typedefs are effectively programmer-opted-in to promotion to register size or something. But compiler optimizations often do the same thing on a per-operation level (signed overflow is UB, unsigned overflow masking can be deferred for addition/subtraction/multiplication and bitwise ops (though some can change the mask)).