cfganal.c (pre_and_rev_post_order_compute_fn): Use an auto_bb_flag instead of an sbitmap for visited handling.

2019-11-21  Richard Biener  <rguenther@suse.de>

	* cfganal.c (pre_and_rev_post_order_compute_fn): Use an
	auto_bb_flag instead of an sbitmap for visited handling.
	* lra.c (lra_insn_recog_data_pool): New.
	(free_insn_recog_data): Adjust.
	(finish_insn_recog_data): Release lra_insn_recog_data_pool.
	(lra_set_insn_recog_data): Allocate from lra_insn_recog_data_pool.
	* tree-ssa-structalias.c (equiv_class_hasher): Change to nofree.
	(equiv_class_obstack): New.
	(equiv_class_lookup_or_add): Allocate from equiv_class_obstack.
	(perform_var_substitution): Initialize equiv_class_obstack.
	(free_var_substitution_info): Free equiv_class_obstack.

From-SVN: r278543