re PR middle-end/19698 (Infinite loop in update_life_info)

re PR middle-end/19698 (Infinite loop in update_life_info)

	PR middle-end/19698
	* function.h (struct function): New field `max_loop_depth'.
	* cfgloop.c (establish_preds): Update maximum loop depth seen so far.
	(flow_loops_find): Reset the max loop depth count before finding loops.
	* flow.c (MAX_LIVENESS_ROUNDS): New constant.
	(update_life_info_in_dirty_blocks): Remove 2002-05-28 workaround.
	(calculate_global_regs_live): Make sure the loop will terminate
	when the initial sets are not empty.

From-SVN: r95299