https://lists.isocpp.org/std-proposals/2023/08/7587.php gives one example where it does. Rust defines what happens for a case that is clearly nonsense, thus rust needs check for that case (on processors where the CPU does something different) even though if you get into it you have a bug in your code.

[–] words_number@programming.dev 2 points 1 year ago

I don't doubt that you can easily craft micro benchmarks out of very specific cases. My point was, that in real world applications, the advantages outweigh the disadvantages easily! And in a very tight loop of performance critical code where this might not be the case, you can still use unsafe and disable checks very carefully where you control the invariants yourself.

[–] words_number@programming.dev 1 points 1 year ago

And, even more importantly: Depending on the use case, that work is not wasted! "You have a bug in your code" is very possible (more unlikely in rust due to its design, but still). If that bug triggers UB, chances are high you habe an exploitable security problem there. If it instead triggers a panic due to rusts checks, the app stopps in a clean way with a decent message and without a security vulnerability.