is in VISITED_BBs

	PR tree-optimization/68013
	* tree-ssa-threadbackward.c
	(fsm_find_control_statement_thread_paths): Make sure the first block
	in the path is in VISITED_BBs.

	PR tree-optimization/68013
	* gcc.c-torture/compile/pr68013.c: New test.

From-SVN: r229375