Definition unary_constructor_sound (cstr: expr -> expr) (sem: val -> val) : Prop :=
  forall le a x,
  eval_expr ge sp e m le a x ->
  exists v, eval_expr ge sp e m le (cstr a) v /\ Val.lessdef (sem x) v.Definition binary_constructor_sound (cstr: expr -> expr -> expr) (sem: val -> val -> val) : Prop :=
  forall le a x b y,
  eval_expr ge sp e m le a x ->
  eval_expr ge sp e m le b y ->
  exists v, eval_expr ge sp e m le (cstr a b) v /\ Val.lessdef (sem x y) v.Definition partial_unary_constructor_sound (cstr: expr -> expr) (sem: val -> option val) : Prop :=
  forall le a x y,
  eval_expr ge sp e m le a x ->
  sem x = Some y ->
  exists v, eval_expr ge sp e m le (cstr a) v /\ Val.lessdef y v.Definition partial_binary_constructor_sound (cstr: expr -> expr -> expr) (sem: val -> val -> option val) : Prop :=
  forall le a x b y z,
  eval_expr ge sp e m le a x ->
  eval_expr ge sp e m le b y ->
  sem x y = Some z ->
  exists v, eval_expr ge sp e m le (cstr a b) v /\ Val.lessdef z v.

Lemma eval_modl_aux: forall divop semdivop, (forall sp x y m, eval_operation ge sp divop (x :: y :: nil) m = semdivop x y) -> forall le a b x y z, eval_expr ge sp e m le a x -> eval_expr ge sp e m le b y -> semdivop x y = Some z -> eval_expr ge sp e m le (modl_aux divop a b) (Val.subl x (Val.mull z y)).