(* This is a rather vacuous lemma, since the premise is simply True *)
(* Lemma Int64_eq_repr_signed32_nonzero: forall i, Int.eq i Int.zero = false -> Int64.eq (Int64.repr (Int.signed i)) Int64.zero = false. *)
(*  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, Int.eq i Int.zero = false -> Int64.eq (cast_int_long s i) Int64.zero = false. *)

Lemma Ptrofs_to_of64_lemma:
Archi.ptr64 = false ->
forall i, Ptrofs.to_int (Ptrofs.of_int64 i) = Int.repr (Int64.unsigned i).