(** ** Properties of [agree_locs] *)
(** Preservation under assignment of machine register. *)

Lemma agree_locs_undef_regs:
forall ls0 regs ls,
agree_locs ls ls0 ->
(forall r, In r regs -> mreg_within_bounds b r) ->
agree_locs (LTL.undef_regs regs ls) ls0.