* tree-ssa-threadupdate.c (threaded_edges): New VEC to
	hold edge pairs.
	(mark_threaded_blocks, register_jump_thread): New functions.
	(thread_through_all_blocks): Remove unwanted argument.  No
	longer rely on e->aux to communicate thread target info.
	Call mark_threaded_blocks.  Release the threaded_blocks
	bitmap and threaded_edges vector when complete.
	* tree-ssa-dom.c (struct edge_info): Remove redirection_target field.
	(threaded_blocks): Remove.
	(tree_ssa_dominator_optimize): Remove initialization and
	finalization of threaded_blocks.  Simplify call to
	thread_through_all_blocks.
	(thread_across_edge): Call register_jump_thread rather than
	storing thread information into e->aux.
	(free_all_edge_infos): Simplify now that e->aux is no longer
	used to communicate with thread_through_all_blocks.
	* tree-flow.h (thread_through_all_blocks): Update prototype.
	(register_jump_thread): Prototype.

From-SVN: r109602