* tree-flow.h (thread_through_all_blocks): Prototype moved into
	tree-ssa-threadupdate.h.
	(register_jump_thread): Similarly.
	* tree-ssa-threadupdate.h: New header file.
	* tree-ssa-dom.c: Include tree-ssa-threadupdate.h.
	* tree-vrp.c: Likewise.
	* tree-ssa-threadedge.c: Include tree-ssa-threadupdate.h.
	(thread_around_empty_blocks): Change type of path vector argument to
	an edge,type pair from just an edge.  Initialize both elements when
	appending to a jump threading path.  Tweak references to elements
	appropriately.
	(thread_across_edge): Similarly.  Release memory for the elements
	as needed.
	* tree-ssa-threadupdate.c: Include tree-ssa-threadupdate.h.
	(dump_jump_thread_path): New function broken out from
	register_jump_thread.
	(register_jump_thread): Use dump_jump_thread_path.  Change type of
	path vector entries.  Search the path for NULL edges and dump
	the path if one is found.  Tweak the conversion of path to 3-edge
	form to use the block copy type information embedded in the path.

	* gcc.dg/tree-ssa/ssa-dom-thread-3.c: Update expected output.

git-svn-id: svn+ssh://gcc.gnu.org/svn/gcc/trunk@202933 138bc75d-0d04-0410-961f-82ee72b054a4