re PR rtl-optimization/69609 (block reordering consumes an inordinate amount of time...

re PR rtl-optimization/69609 (block reordering consumes an inordinate amount of time, REE consumes much memory)

2016-02-17  Richard Biener  <rguenther@suse.de>

	PR rtl-optimization/69609
	* bb-reorder.c (struct bbro_basic_block_data): Add priority member.
	(find_traces_1_round): When ending a trace update cached priority
	of successors.
	(bb_to_key): Use cached priority when available.
	(copy_bb): Initialize cached priority.
	(reorder_basic_blocks_software_trace_cache): Likewise.

From-SVN: r233498