Inductive transl_lblstmt_cont(cenv: compilenv) (xenv: exit_env): lbl_stmt -> cont -> cont -> Prop :=
| tlsc_default: forall k,
transl_lblstmt_cont cenv xenv LSnil k (Kblock (Kseq Sskip k))
| tlsc_case: forall i s ls k ts k',
transl_stmt cenv (switch_env (LScons i s ls) xenv) s = OK ts ->
transl_lblstmt_cont cenv xenv ls k k' ->
transl_lblstmt_cont cenv xenv (LScons i s ls) k (Kblock (Kseq ts k')).

Lemma switch_ascent:
forall f sp e m cenv xenv ls n ls',
lbl_stmt_tail ls n ls' ->
forall k k1,
transl_lblstmt_cont cenv xenv ls k k1 ->
exists k2,
star step tge (State f (Sexit n) k1 sp e m)
E0 (State f (Sexit O) k2 sp e m)
/\ transl_lblstmt_cont cenv xenv ls' k k2.