But even integer overflow is undefined.

It's practically impossible to find a program without UB.

I think this is not really true. Or rather, it depends on the UB you are talking about. There is UB which is simply UB because it is out-of-scope for the C standard, and there is UB such as signed integer overflow that can cause issues. It is realistic to deal with the later, e.g. by converting them to traps with a compiler flags.

	▲	zephen 13 minutes ago \| parent [-]
		> I think this is not really true. Or rather, it depends on the UB you are talking about. I mean, if you're going to argue that a compiler can do anything with any UB, then by all means make that argument. Otherwise, then no, I don't think it's reasonable for a compiler to cause an infinite loop inside a function simply because that function itself doesn't return a value.