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.