2009-04-20  Jan Beulich  <jbeulich@novell.com>

	* expr.c (operand): Call md_need_index_operator() and
	md_operator() if defined. Add unary label.
	(operator): Call md_operator() if defined.
	(expr): Adjust assertions on range and rank of op_left and
	op_right. Don't abort on unhandled operators when reducing
	expressions with both operands being constant.
	(expr_set_rank): New.
	* expr.h (expr_set_rank): Declare.