Signed wrapping behavior is well-defined in the machine language for every architecture that ever existed (or at least, that I've ever heard of). If the assemb

Signed wrapping behavior is well-defined in the machine language for every architecture that ever existed (or at least, that I've ever heard of). If the assembly code depends on the wrapping behavior and you translated that to C, you'd get C code that depends on the behavior of signed overflow, which the compiler is free to completely remove, no matter your target. This is a somewhat extreme case, as code that depends on the behavior of signed overflow is rare, but there's a lot of things that are perfectly well specified by the architecture, but that C leaves undefined.