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I wouldn't be too sure about that. Rust gives more compile-time guarantees, allowing the compiler not to emit code for otherwise plausible conditions (see eg. pointer aliasing); on the other hand, C compilers typically rely on undefined behaviour to apply optimisations, whereas Rust may not have as much undefined behaviour due to its safety.

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Safe Rust has no UB, outside of some bugs, to be clear.

That said, optimization is all about guarantees: this broad of a claim (UB vs info) because both are about what's guaranteed, and what's not. That is, they play similar roles, so you'd have to be comparing how much of each is in what amount in what code.

We generally expect Rust to be roughly as fast as C, sometimes faster, sometimes slower. Modulo optimizer bugs in each case, of course.

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