re PR middle-end/54364 (Tail call jumps not threaded)

re PR middle-end/54364 (Tail call jumps not threaded)

	PR middle-end/54364
	* bb-reorder.c (connect_better_edge_p): New added.
	(find_traces_1_round): When optimizing for size, ignore edge frequency
	and probability, and handle all in one round.
	(bb_to_key): Use bb->index as key when optimizing for size.
	(better_edge_p): The bb with smaller index is better when optimizing
	for size.
	(connect_traces): When optimizing for size, connect block n with
	block n + 1; connect trace m with trace m + 1 if falling through.
	(gate_handle_reorder_blocks): Enable bbro when optimizing for -Os.

From-SVN: r191462