Right, but I had thought that clang would have done something involving deducing the bounds of n, which could be used to avoid overflow in later optimizations.

Right, but I had thought that clang would have done something involving deducing the bounds of n, which could be used to avoid overflow in later optimizations. Now that I think about it, though, they key there is "could" - overflow could be avoided by deducing bounds, but if said deduction can't occur then what you describe sounds like the most natural action to take as long as there aren't other issues.