“Provenance” is about the object that a pointer refers to. In your example, i and j are different objects and the language does not permit you to modify j using a pointer derived from i.

Your comparison with parallel loops is interesting because in the case of big arrays, all the pointers refer to the same object, so the compiler can’t use provenance or strict aliasing to prove that they don’t overlap. So you have to use the pragmas to give the compiler permission to treat them as non-aliasing.