> For example, if signed integer overflow yielded an unspecified result rather than causing undefined behavior, I wonder if any implementations would be adverse

> For example, if signed integer overflow yielded an unspecified result rather than causing undefined behavior, I wonder if any implementations would be adversely affected. Yes. There are several architectures where signed integer overflow traps, just like division by 0 on x86. (which is why division by 0 is UB) If a C compiler for those architectures was required to yield an unspecified result instead of trapping, every time the code performed a signed integer addition/subtraction, it would need to update a trap handler before and afterward to return an unspecified value instead of invoking the normal trap handler.