re PR tree-optimization/68541 (Path splitting causes if-conversion miss)

re PR tree-optimization/68541 (Path splitting causes if-conversion miss)

	PR tree-optimization/68541
	* gimple-ssa-split-paths.c: Include tree-cfg.h and params.h.
	(count_stmts_in_block): New function.
	(poor_ifcvt_candidate_code): Likewise.
	(is_feasible_trace): Add some heuristics to determine when path
	splitting is profitable.
	(find_block_to_duplicate_for_splitting_paths): Make sure the graph
	is a diamond with a single exit.

        PR tree-optimization/68541
	* gcc.dg/tree-ssa/split-path-2.c: New test.
	* gcc.dg/tree-ssa/split-path-3.c: New test.
	* gcc.dg/tree-ssa/split-path-4.c: New test.
	* gcc.dg/tree-ssa/split-path-5.c: New test.
	* gcc.dg/tree-ssa/split-path-6.c: New test.
	* gcc.dg/tree-ssa/split-path-7.c: New test.

From-SVN: r233191