CBTune: Contextual Bandit Tuning for Logic Synthesis

Logic synthesis pre-optimization involves applying a sequence of transformations called synthesis flow to reduce the circuit's Boolean logic graph, like AIG. However, the challenge lies in selecting and arranging these transformations due to the exponentially expanding solution space. In this work, we propose CBTune, a novel online learning framework that utilizes a contextual bandit algorithm to explore the solution space and generate synthesis flows efficiently. We develop the Syn-LinUCB algorithm as the agent, which incorporates circuit characteristics and leverages long-term payoffs to guide decision-making, thus ef-fectively preventing getting trapped in local optima. Experimental results show that our framework achieves the optimal synthesis flow with a lower time cost, substantially reducing the number of AIG nodes and 6-LUTs compared to SOTA approaches.