Actually that made me think... you might be right. I just saw this opinion in earlier threads and repeated it but upon second inspection I either remembered it wrongly, or it is a wrong theory.

I think the issue is more the side effects than the panic message. I have tried making a side effect free loop like for i in 0..44 { v[i]; } but it compiled down to a "if array length is larger than limit X, then call panic_bounds_check". On the other hand, if you replace the v[i] with soon-stable black_box(v[i]), you see that the loop remains. It doesn't know what black_box is doing so it has to run the code. The optimizer is in this case very happy if you have a check before the loop.

https://rust.godbolt.org/z/5x46edeTb