Definition must_return (ek: exitkind) : bool :=
match ek with EK_return => true | _ => false end.

Lemma eliminate_extra_return:
forall Espec {cs: compspecs} Delta P c ty Q Post,
quickflow c must_return = true ->
Post = (function_body_ret_assert ty Q) ->
@semax cs Espec Delta P c Post ->
@semax cs Espec Delta P (Ssequence c (Sreturn None)) Post.