[jjnoakes]

I disagree.

If I write a routine which walks an array one element at a time, in order, up to some max index N, and also stops early when it reaches some other condition (like an element equal to zero), then I am allowed to pass in memory which is only 3 elements long, and an N greater than 3, if I know that there is a zero in the first 3 elements. The function must not be optimized to read past the zero element, regardless of the N passed in, so removing the early exit would be an invalid optimization.

There's no undefined behavior in the above that justifies that optimization.