Heh, you're right, good catch: https://godbolt.org/z/3cEfbqM51 https://godbolt.org/z/3cEfbqM51 Looks like their (Rust) main motivator was readability. Whereas

Heh, you're right, good catch: https://godbolt.org/z/3cEfbqM51 https://godbolt.org/z/3cEfbqM51 Looks like their (Rust) main motivator was readability. Whereas P3330R0 has that + performance on non-CAS hardware in mind. In any case, Rust's function could be optimized in the future, if they decide on it.