type range = {mutable rbegin : int;mutable rend : int;
}type t = {mutable reg : Reg.t;mutable ibegin : int;mutable iend : int;mutable ranges : range list;
}type result = {intervals : t list;fixed_intervals : t list;
}val overlap : t -> t -> boolval is_live : t -> int -> boolval remove_expired_ranges : t -> int -> unit