tree-cfg.c (gimple_can_merge_blocks_p): Do more fine-grained check whether SSA form is not up-to-date.

2012-07-27  Richard Guenther  <rguenther@suse.de>

	* tree-cfg.c (gimple_can_merge_blocks_p): Do more fine-grained
	check whether SSA form is not up-to-date.
	* tree-flow.h (name_mappings_registered_p): Remove.
	* tree-into-ssa.c (struct repl_map_d): Remove.
	(repl_tbl): Likewise.
	(struct ssa_name_info): Add repl_set member.
	(update_ssa_obstack): New static global.
	(get_ssa_name_ann): Initialize repl_set.
	(clear_ssa_name_info): Assert age did not wrap.
	(repl_map_hash, repl_map_eq, repl_map_free): Remove.
	(names_replaced_by): Adjust.
	(add_to_repl_tbl): Likewise.
	(dump_tree_ssa_stats): Likewise.
	(init_update_ssa): Initialize update_ssa_obstack.
	(delete_update_ssa): Free update_ssa_obstack.
	(name_mappings_registered_p): Remove.
	(update_ssa): Adjust.

From-SVN: r189915