* ira.h (ira_conflicts_p): New external definition.
* ira-conflicts.c (build_conflict_bit_table): Do not build too big
table. Report this. Return result of building.
(ira_build_conflicts): Use ira_conflicts_p. Check result of
building conflict table.
* ira-color.c (fast_allocation): Use num instead of
ira_allocnos_num.
(ira_color): Use ira_conflicts_p.
* global.c: Include ira.h.
(pseudo_for_reload_consideration_p, build_insn_chain): Use
ira_conflicts_p.
* Makefile.in (global.o): Add ira.h.
* ira-build.c (mark_all_loops_for_removal,
propagate_some_info_from_allocno): New.
(remove_unnecessary_allocnos): Call
propagate_some_info_from_allocno.
(remove_low_level_allocnos): New.
(remove_unnecessary_regions): Add parameter. Call
mark_all_loops_for_removal and remove_low_level_allocnos. Pass
parameter to remove_unnecessary_regions.
(ira_build): Remove all regions but root if the conflict table was
not built. Update conflict hard regs for allocnos crossing calls.
* ira.c (ira_conflicts_p): New global.
(ira): Define and use ira_conflicts_p.