[jforberg]

That sounds reasonable. I agree that overflow is often a bug (and in GCC can use -ftrapv to enforce that view). But overflow is also frequently what you want in algorithms that deal with counters or differences of sums. Maybe point out that there are well-defined operators available in Zig as well?

I'm not immediately seeing how non-wrapping arithmetic can enable significant optimisation. What could be faster than an integer add? If you have an example, I would be very interested (the classic "infinite loop" example is not particularly meaningful in my view).

I always assumed that C left this undefined mostly to support non-two's complement machines, which should probably not be a concern anymore. That's the only explanation I can come up with that explains why unsigned arithmetic is well-defined, but not signed arithmetic.