Improving Netlist Transformation-Based Approximate Logic Synthesis Through Resynthesis

To address the challenges of efficient hardware design for error-tolerant applications, several techniques of applied approximate computing have been proposed. Pruning algorithms aim to approximate circuits with reduced design requirements at the cost of an acceptable degradation of their quality-of-result. In this letter, we present the effects of resynthesis, an iterative application of logic synthesis along with pruning algorithms, into a state-of-the-art approximate design flow, AxLS. Resynthesis strategy improve the approximation, achieving up to 70% area-power savings for the same error in the output, and reducing the number of iterations, and hence the time required to explore the design space in up to 30×, to obtain an approximated design.