* genattrtab.c (simplify_test_exp_in_temp): New function.
        (simplify_test_exp): Avoid explicit use of temporary obstack.
        (simplify_cond, insert_right_side, evaluate_eq_attr,
        simplify_and_tree, simplify_or_tree, eliminate_known_true):
        Use simplify_test_exp_in_temp.
        (optimize_attrs): Iterate until expression stabilizes.

From-SVN: r44890