(** Correctness of [add_branch]. *)

Lemma add_branch_correct:
forall lbl c k s f tf sp ls m,
transf_function f = OK tf ->
is_tail k tf.(fn_code) ->
find_label lbl tf.(fn_code) = Some c ->
plus step tge (State s tf sp (add_branch lbl k) ls m)
E0 (State s tf sp c ls m).