tree-ssa-threadupdate.c (THREAD_TARGET): define.

	* tree-ssa-threadupdate.c (THREAD_TARGET): define.
	(remove_ctrl_stmt_and_useless_edges): Clear AUX field of outgoing edges.
	(craete_edge_and_update_destination_phis): Use THREAD_TARGET rather
	than accessing AUX field directly.  Free the AUX field before			clearing it.
	(thread_block, thread_through_loop_header): Likewise.
	(thread_single_edge, mark_threaded_blocks): Likewise.
	(redirect_edges): Delay clearing the AUX field.  Free the AUX field.
	(register_jump_thread): Do not attempt to thread to a NULL edge.

From-SVN: r173305