Design.routeSites() unable to route Carry8 DI0 to site pin.

[haydenc-amd]

I am trying to route an adder/subtractor DCP using RWRoute. However, it is failing in the Design.routeSites() function, saying it is unable to route a Carry8 DI0 to a site pin.

Here is my code:

package com.xilinx.rapidwright.llm;

import com.xilinx.rapidwright.design.Design;
import com.xilinx.rapidwright.rwroute.RWRoute;

public class RippleCarryTest {
    public static void main(String[] args) {
        Design d = Design.readCheckpoint("ripple_carry_sub_add-0.dcp");
        d.routeSites();
        d=RWRoute.routeDesignFullNonTimingDriven(d);
        d.writeCheckpoint("ripple_carry_sub_add-0.routed.dcp");
    }
}

Here is the corresponding DCP (renamed to .zip): ripple_carry_sub_add-0.zip