(* The following two lemmas is not now used. but after deep embedded hoare logic (SL_as_Logic) is ported, the frame does not need to be quantified in the semantic definition of semax. Then, these two lemmas can replace the other two afterwards. *)

Lemma rguard_except_0:
forall {Espec: OracleKind} ge Delta (F: environ -> pred rmap) Q k,
rguard Espec ge Delta (frame_ret_assert Q F) k =
rguard Espec ge Delta (frame_ret_assert (except_0_ret_assert Q) F) k.