* tree-ssa-threadedge.c (thread_across_edge): Make path a pointer to
	a vec.  Only delete the path if we create one without successfully
	registering a jump thread.
	* tree-ssa-threadupdate.h (register_jump_thread): Pass in path vector
	as a pointer.
	* tree-ssa-threadupdate.c (threaded_edges): Remove.  No longer used
	(paths): New vector of jump threading paths.
	(THREAD_TARGET, THREAD_TARGET2): Remove accessor macros.
	(THREAD_PATH): New accessor macro for the entire thread path.
	(lookup_redirection_data): Get intermediate and final outgoing edge
	from the thread path.
	(create_edge_and_update_destination_phis): Copy the threading path.
	(ssa_fix_duplicate_block_edges): Get edges and block types from the
	jump threading path.
	(ssa_redirect_edges): Get edges and block types from the jump threading
	path.  Free the path vector.
	(thread_block): Get edges from the jump threading path.  Look at the
	entire path to see if we thread to a loop exit.  If we cancel a jump
	thread request, then free the path vector.
	(thread_single_edge): Get edges and block types from the jump threading
	path.  Free the path vector.
	(thread_through_loop_header): Get edges and block types from the jump
	threading path.  Free the path vector.
	(mark_threaded_blocks): Iterate over the vector of paths and store
	the path on the appropriate edge.  Get edges and block types from the
	jump threading path.
	(mark_threaded_blocks): Get edges and block types from the jump
	threading path.  Free the path vector.
	(thread_through_all_blocks): Use the vector of paths rather than
	a vector of 3-edge sets.
	(register_jump_thread): Accept pointer to a path vector rather
	than the path vector itself.  Store the path vector for later use.
	Simplify.

From-SVN: r203061