Ltac comput val :=
  let x := fresh in set val as x in *; vm_compute in x; subst x.Remark small_shift_amount_1:
  forall i,
  Int64.ltu i Int64.iwordsize = true ->
  Int.ltu (Int64.loword i) Int64.iwordsize' = true
  /\ Int64.unsigned i = Int.unsigned (Int64.loword i).Remark small_shift_amount_2:
  forall i,
  Int64.ltu i (Int64.repr 32) = true ->
  Int.ltu (Int64.loword i) Int.iwordsize = true.

Lemma small_shift_amount_3: forall i, Int.ltu i Int64.iwordsize' = true -> Int64.unsigned (Int64.repr (Int.unsigned i)) = Int.unsigned i.