MORPH: More Robust ASIC Placement for Hybrid Region Constraint Management

Modern ASIC placement tools encompass three categories of region constraints: default regions, fence regions, and guide regions. Region constraints pose significant challenges to existing placement algorithms, compromising the versatility and robustness required for diverse placement workloads. In this work, we propose MORPH, a more robust ASIC placer designed for hybrid region constraints. We integrate hybrid region constraints into a unified multi-electrostatic formulation that features a shared electrostatics model and a binary-lifting-based region pruning algorithm. We develop a more robust nonlinear placement framework that includes second-order information and a hybrid-region-aware legalization algorithm to address convergence issues. Experiments on the ISPD 2015 benchmark suite demonstrate 5.6-14.3% HPWL improvement and 10--24% overflow reduction compared to state-of-the-art region-aware placers. Further experiments on the ISPD 2015 benchmark suite and its variants show that the proposed techniques can achieve over 30% HPWL improvement and up to a twofold reduction in overflow with more stable convergence.