Convert internal representation of irange to wide_ints.

Convert internal representation of irange to wide_ints.

gcc/ChangeLog:

	* range-op.cc (update_known_bitmask): Adjust for irange containing
	wide_ints internally.
	* tree-ssanames.cc (set_nonzero_bits): Same.
	* tree-ssanames.h (set_nonzero_bits): Same.
	* value-range-storage.cc (irange_storage::set_irange): Same.
	(irange_storage::get_irange): Same.
	* value-range.cc (irange::operator=): Same.
	(irange::irange_set): Same.
	(irange::irange_set_1bit_anti_range): Same.
	(irange::irange_set_anti_range): Same.
	(irange::set): Same.
	(irange::verify_range): Same.
	(irange::contains_p): Same.
	(irange::irange_single_pair_union): Same.
	(irange::union_): Same.
	(irange::irange_contains_p): Same.
	(irange::intersect): Same.
	(irange::invert): Same.
	(irange::set_range_from_nonzero_bits): Same.
	(irange::set_nonzero_bits): Same.
	(mask_to_wi): Same.
	(irange::intersect_nonzero_bits): Same.
	(irange::union_nonzero_bits): Same.
	(gt_ggc_mx): Same.
	(gt_pch_nx): Same.
	(tree_range): Same.
	(range_tests_strict_enum): Same.
	(range_tests_misc): Same.
	(range_tests_nonzero_bits): Same.
	* value-range.h (irange::type): Same.
	(irange::varying_compatible_p): Same.
	(irange::irange): Same.
	(int_range::int_range): Same.
	(irange::set_undefined): Same.
	(irange::set_varying): Same.
	(irange::lower_bound): Same.
	(irange::upper_bound): Same.