tree-ssa-threadedge.c: Remove include of tree-ssa-threadbackward.h.

	* tree-ssa-threadedge.c: Remove include of tree-ssa-threadbackward.h.
	(thread_across_edge): Remove calls to find_jump_threads_backwards.
	* passes.def: Add jump threading passes before DOM/VRP.
	* tree-ssa-threadbackward.c (find_jump_threads_backwards): Change
	argument to a basic block from an edge.  Remove tests which are
	handled elsewhere.
	(pass_data_thread_jumps, class pass_thread_jumps): New.
	(pass_thread_jumps::gate, pass_thread_jumps::execute): New.
	(make_pass_thread_jumps): Likewise.
	* tree-pass.h (make_pass_thread_jumps): Declare.

	* gcc.dg/tree-ssa/pr21417.c: Update expected output.
	* gcc.dg/tree-ssa/pr66752-3.c: Likewise.
	* gcc.dg/tree-ssa/pr68198.c: Likewise.
	* gcc.dg/tree-ssa/pr69196-1.c: Likewise.
	* gcc.dg/tree-ssa/pr69270-3.c: Likewise.
	* gcc.dg/tree-ssa/ssa-dom-thread-2b.c: Likewise.
	* gcc.dg/tree-ssa/ssa-dom-thread-2g.c: Likewise.
	* gcc.dg/tree-ssa/ssa-dom-thread-2h.c: Likewise.
	* gcc.dg/tree-ssa/ssa-dom-thread-6.c: Likewise.
	* gcc.dg/tree-ssa/ssa-dom-thread-7.c: Likewise.
	* gcc.dg/tree-ssa/ssa-dom-thread-12.c: Likewise.
	* gcc.dg/tree-ssa/ssa-dom-thread-13.c: Likewise.
	* gcc.dg/tree-ssa/vrp56.c: Likewise.

From-SVN: r236831