Fast floorplanning by look-ahead enabled recursive bipartitioning

A new paradigm is introduced for floorplanning any combination of fixed-shape and variable-shape blocks under tight fixed-outline area constraints and a wirelength objective. Dramatic improvement over traditional floor-planning methods is achieved by explicit construction of strictly legal layouts for every partition block at every level of a cutsize-driven, top-down hierarchy. By scalably incorporating legalization into the hierarchical flow, post-hoc legalization is successfully eliminated. For large floorplanning benchmarks, an implementation, called PATOMA, generates solutions with half the wirelength of state-of-the-art floorplanners in orders of magnitude less run time.