This paper presents a novel placement algorithm for timing optimization based on a new and powerful concept, which we term differential timing analysis. Recognizing that accurate optimization requires timing information from a signoff static timing analyzer, we propose an incremental placement algorithm that uses timing information from a signoff static timing engine. We propose a set of differential timing analysis equations that accurately capture the effect of placement perturbations on changes in timing from the signoff timer. We have fotmutated an incremental placement optimization problem based on differential timing analysis as a single linear programming (LP) problem which is solved to generate thc new timing-optimized placement.Our experiments show that the worst negative slack (WNS) improves by an average of 30% and the total negative slack (TNS) improves by 33% on average for a set of circuits from a 3.0 GHz microprocessor that were already synthesized and placed by a leading industrial physical synthesis tool. We also show that multiple iterations of our engine give further TNS improvements an average improvement of 5 1 %, which implies that our placer will significantly speed up timing convergence.

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