I'm not entirely sure how that is an example I asked for. In this case, it seems like the compiler in both cases was able to see that the loop always terminates

I'm not entirely sure how that is an example I asked for. In this case, it seems like the compiler in both cases was able to see that the loop always terminates, either by hitting 0 directly, or by wrapping around and then hitting 0, or by simply assuming integer underflow to be UB.