PR tree-optimization/69196

	PR tree-optimization/69196
	PR tree-optimization/68398
	* tree-ssa-threadupdate.h (enum bb_dom_status): Moved here from
	tree-ssa-threadupdate.c.
	(determine_bb_domination_status): Prototype
	* tree-ssa-threadupdate.c (enum bb_dom_status): Remove
	(determine_bb_domination_status): No longer static.
	(valid_jump_thread_path): Remove code to detect characteristics
	of the jump thread path not associated with correctness.
	* tree-ssa-threadbackward.c (fsm_find_control_statment_thread_paths):
	Correct test for thread path length.  Count PHIs for real operands as
	statements that need to be copied.  Do not count ASSERT_EXPRs.
	Look at all the blocks in the thread path.  Compute and selectively
	filter thread paths based on threading through the latch, threading
	a multiway branch or crossing a multiway branch.

	PR tree-optimization/69196
	PR tree-optimization/68398
	* gcc.dg/tree-ssa/pr66752-3.c: Update expected output
	* gcc.dg/tree-ssa/pr68198.c: Likewise.

git-svn-id: svn+ssh://gcc.gnu.org/svn/gcc/trunk@232802 138bc75d-0d04-0410-961f-82ee72b054a4