(** Correctness of [labels_branched_to]. *)
Definition instr_branches_to (i: instruction) (lbl: label) : Prop :=
match i with
| Lgoto lbl' => lbl = lbl'
| Lcond cond args lbl' => lbl = lbl'
| Ljumptable arg tbl => In lbl tbl
| _ => False
end.
Remark add_label_branched_to_incr:
forall ls i, Labelset.Subset ls (add_label_branched_to ls i).
Remark add_label_branched_to_contains:
forall ls i lbl,
instr_branches_to i lbl ->
Labelset.In lbl (add_label_branched_to ls i).

(* Specifications: *)
Lemma labels_branched_to_correct:
forall c i lbl,
In i c -> instr_branches_to i lbl -> Labelset.In lbl (labels_branched_to c).