The key methodologies of modern logic synthesis techniques are conducted on multi-level technology-independent representations such as And-Inverter-Graphs (AIGs) of the digital logic via directed-acyclic-graph (DAGs) traversal based structural rewriting, resubstitution, and refactoring. Existing state-of-the-art DAG-aware logic synthesis algorithms are all designed to perform stand-alone optimizations during a single DAG traversal. However, we empirically identify and demonstrate that these algorithms are limited in quality-of-results and runtime complexity due to this design concept. This work proposes Synthesis Orchestration, which orchestrates stand-alone operations within the single traversal of AIG. Thus, orchestration method explores more optimization opportunities and results in better performance. Our experimental results are comprehensively conducted on all 104 designs collected from ISCAS'85/89/99, VTR, and EPFL benchmark suites, with consistent logic minimization improvements over rewriting, resubstitution, refactoring, leading to an average of 4% more node reduction with improved runtime efficiency for the single optimization. Moreover, we evaluate orchestration as a plug-in algorithm in resyn and resyn3 flows in ABC, which demonstrates consistent logic minimization improvements (3.8% and 10.9% more node reduction on average). The runtime analysis demonstrates the orchestration outperforms stand-alone algorithms in both AIG minimization and runtime efficiency. Finally, we integrate the orchestration into OpenROAD for end-to-end performance evaluation. Our results demonstrate the advantages of the orchestration optimization technique, even after technology mapping and post-routing in the design flow have been conducted.

翻译：现代逻辑综合技术的核心方法基于数字逻辑的与非门图（AIG）等多级技术无关表示，通过有向无环图（DAG）遍历的结构重写、重新代入和重构进行优化。现有最先进的DAG感知逻辑综合算法均设计为在单次DAG遍历期间执行独立优化。然而，我们通过实验发现并证明，这种设计理念限制了算法的结果质量与运行时间复杂度。本文提出综合编排（Synthesis Orchestration），在单次AIG遍历中协调独立操作，从而探索更多优化机会并实现更优性能。我们对ISCAS'85/89/99、VTR和EPFL基准测试套件中的所有104个设计进行了全面实验，结果表明：与重写、重新代入和重构相比，该编排方法在单次优化中实现了平均4%的额外节点缩减，同时提升了运行效率。进一步地，我们将编排作为插件算法集成到ABC工具的重综合和重综合3流程中，持续展现出逻辑最小化改进（平均节点缩减分别提升3.8%和10.9%）。运行时间分析表明，该编排方法在AIG最小化和运行效率两方面均优于独立算法。最后，我们将编排技术集成至OpenROAD进行端到端性能评估，结果表明即使在设计流程完成技术映射和后布线后，该优化技术仍具有显著优势。