(*  Lemma Int64_eq_repr_unsigned32_nonzero: forall i, Int.eq i Int.zero = false -> Int64.eq (Int64.repr (Int.unsigned i)) Int64.zero = false. *)

Lemma Int64_eq_repr_int_nonzero:
forall s i, i <> Int.zero ->
cast_int_long s i <> Int64.zero.