(** 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 n => Int.eq (Int.sign_ext 12 n) n
  | Olongconst n => Int64.eq (Int64.sign_ext 12 n) n
  | Oaddrstack _ => true
  | _ => false
  end.(** Operations that depend on the memory state. *)

Definition op_depends_on_memory (op: operation) : bool :=
  match op with
  | Ocmp (Ccompu _) => negb Archi.ptr64
  | Ocmp (Ccompuimm _ _) => negb Archi.ptr64
  | Ocmp (Ccomplu _) => Archi.ptr64
  | Ocmp (Ccompluimm _ _) => Archi.ptr64
  | _ => false
  end.

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.