GRPlacer: improving routability and wire-length of global routing with circuit replacement

Placement profoundly impacts physical design owing to its role in determining the lower bound of a circuit wirelength, as well as the circuit routability. To close the gap between placement and routing, this study integrates global routing and placement to improve the wirelength estimation accuracy of placement. Two methods, called wirelength-reduced cell shifting and cell rearrangement by bipartite matching, are applied to minimize wirelength. Cell sorting based congestion reduction and pattern-prerouting based congestion-avoided cell shifting are proposed to reduce congestion. Experimental results demonstrate that the proposed placer improves total routed wirelength by 2% to ROOSTER on IBMv2 benchmarks. Moreover, the proposed GRPlacer resolves the original congested regions of the placements generated by ROOSTER. Compare with the detailed placer in ROOSTER, our work can reduce more routed wire length and remove more overflows.