gimple-low.c (struct lower_data): Replace the_return_label and one_return_stmt with return_statements.

        * gimple-low.c (struct lower_data): Replace the_return_label and
        one_return_stmt with return_statements.
        (lower_function_body): Process the entire list of return_statements.
        (lower_return_expr): Check source value before unifying return_exprs.
        * gimplify.c (gimplify_return_expr): Force the use of a temporary
        for !aggregate_value_p.
        * tree-gimple.c: Update RETURN_EXPR grammer.

From-SVN: r82768