1. Warning 297: Some blocks are impossible to connect in this architecture.
  2. Cannot route from BLK_TL-PLB.o_sp4_v_b[44] (rr_node: 4294 type: SOURCE ptc: 614 xlow: 3 ylow: 2) to BLK_TL-PLB.carry_in[0] (rr_node: 3680 type: SINK ptc: 0 xlow: 3 ylow: 2) to -- no possible path
  3. Failed to route connection from '$auto$alumacc.cc:474:replace_alu$5.slice[1].carry' to '$auto$alumacc.cc:474:replace_alu$5.slice[1].carry' for net 'counter[0]'
  4. Routing failed.