type t = | Source| Parsetree| Typedtree| Shape| Match_comp| Raw_lambda| Lambda| Instr| Raw_clambda| Clambda| Raw_flambda| Flambda| Cmm| Selection| Combine| CSE| Live| Spill| Split| Interf| Prefer| Regalloc| Scheduling| Linear| Interval
val compare : t -> t -> intval of_string : string -> t optionval to_string : t -> string