(** Operations that are so cheap to recompute that CSE should not factor them out. *)

Definition is_trivial_op (op: operation) : bool :=
  match op with
  | Omove => true
  | Ointconst _ => true
  | Oaddrsymbol _ _ => true
  | Oaddrstack _ => true
  | _ => false
  end.(** Operations that depend on the memory state. *)

Definition op_depends_on_memory (op: operation) : bool :=
  match op with
  | Ocmp (Ccompu _) => true
  | Ocmp (Ccompuimm _ _) => true
  | Ocmp (Ccomplu _) => Archi.ppc64
  | Ocmp (Ccompluimm _ _) => Archi.ppc64
  | _ => false
  end.

(* Specifications: *)
Lemma op_depends_on_memory_correct: forall (F V: Type) (ge: Genv.t F V) sp op args m1 m2, op_depends_on_memory op = false -> eval_operation ge sp op args m1 = eval_operation ge sp op args m2.