* lcm.c (optimize_mode_switching): Do not rebuild liveness information
when no changes has been made.
* gcse.c (reg_set_bitmap): Turn into reg_set.
(modify_mem_list_set, canon_modify_mem_list_set)
(clear_modify_mem_tables, free_modify_mem_tables): New.
(gcse_main); Use free_modify_mem_tables.
(free_gcse_mem): Likewise; free the bitmaps.
(alloc_gcse_main): Initialize the bitmaps.
(canon_list_insert): Set canon_modify_mem_list_set.
(record_last_mem_set_info): Likewise; set modify_mem_list_set.
(compute_hash_table): Use clear_modify_mem_tables.
(reset_opr_set_tables): Likewise.
(oprs_not_set_p): reg_set_bitmap is regset.
(mark_set, mark_clobber): Likewise.
* df.h (DF_EQUIV_NOTES): New constant.
(df_insn_refs_record): Record uses inside or REG_EQUIV/EQUAL notes
when asked for.
* sched-rgn.c (CHECK_DEAD_NOTES): New constant.
(init_regions, schedule_insns): Conditionalize the checking
code by CHECK_DEAD_NOTES; avoid multiple calls to update_life_info.
From-SVN: r46634
