fold-const.c (combine_comparisons, [...]): Use constant_boolean_node where appropriate.

fold-const.c (combine_comparisons, [...]): Use constant_boolean_node where appropriate.

	* fold-const.c (combine_comparisons, optimize_bit_field_compare,
	range_binop, fold_truthop, fold_binary_op_with_conditional_arg,
	fold_mathfn_compare, fold_inf_compare, fold,
	fold_relational_hi_lo, nondestructive_fold_binary_to_constant):
	Use constant_boolean_node where appropriate.  Don't bother using
	fold_convert on the second argument to omit_one_operand.

From-SVN: r82468