综合后遇到【shape builder 18-138】 cannot obey LUTNM/HLUTNM constrain for instances rx_agc_din[5]_i_29 and rx_agc_din[5]_i_34. Reason: for bel A5LUT Element SLICE_X2Y0. A6LUT is not routable as there as 6 input pins and A6 cannot be used of A5LUT usage..这个critical warning,但在布局布线的时候会报错,请问这是怎么回事?谢谢