Tweaks to ranger cache

Tweaks to ranger cache

Add some bounds checking to ssa_block_ranges, and privatize the
ranges block cache and global cache, adding API points for accessing them.

	* gimple-range-cache.h (block_range_cache): Add new entry point.
	(ranger_cache): Privatize global abnd block cache members.
	* gimple-range-cache.cc (ssa_block_ranges::set_bb_range): Add bounds
	check.
	(ssa_block_ranges::set_bb_varying): Ditto.
	(ssa_block_ranges::get_bb_range): Ditto.
	(ssa_block_ranges::bb_range_p): Ditto.
	(block_range_cache::get_block_ranges): Fix formatting.
	(block_range_cache::query_block_ranges): New.
	(block_range_cache::get_bb_range): Use Query_block_ranges.
	(block_range_cache::bb_range_p): Ditto.
	(ranger_cache::dump): New.
	(ranger_cache::get_global_range): New.
	(ranger_cache::set_global_range): New.
	* gimple-range.cc (gimple_ranger::range_of_expr): Use new API.
	(gimple_ranger::range_of_stmt): Ditto.
	(gimple_ranger::export_global_ranges): Ditto.
	(gimple_ranger::dump): Ditto.