* rtl.h (subrtx_p): Renamed to rtx_referenced_p.
(rtx_pair): Added new element update_label_nuses, renamed to
replace_label_data.
* cfgcleanup.c (outgoing_edges_match, try_crossjump_to_edge): Use
replace_label_data instead of rtx_pair.
* loop.c (load_mems): Likewise.
* rtlanal.c (replace_label): Replace label in pool constants and in
INSN_LIST (in REG_LABEL note).
(subrtx_p): Renamed to rtx_referenced_p.
(subrtx_p_1): Renamed to rtx_referenced_p_1, compare the interior of
LABEL_REF with CODE_LABEL, traverse constants from pool.