Definition modlu (v w: aval) :=
  match w, v with
  | L i2, L i1 =>
      if Int64.eq i2 Int64.zero
      then if va_strict tt then Vbot else ntop
      else L (Int64.modu i1 i2)
  | _, _ => ntop2 v w
  end.

Lemma modlu_sound: forall v w u x y, vmatch v x -> vmatch w y -> Val.modlu v w = Some u -> vmatch u (modlu x y).