Agglomerative-based flip-flop merging with signal wirelength optimization

In this paper, an optimization methodology using agglomerative-based clustering for number of flip-flop reduction and signal wirelength minimization is proposed. Comparing to previous works on flip-flop reduction, our method can obtain an optimal tradeoff curve between flip-flop number reduction and increase in signal wirelength. Our proposed methodology outperforms [1] and [12] in both reducing number of flip-flops and minimizing increase in signal wirelength. In comparison with [9], our methodology obtains a tradeoff of 15.8% reduction in flip-flop´s signal wirelength with 16.9% additional flip-flops. Due to the nature of agglomerative clustering, when relocating flip-flops, our proposed method minimizes total displacement by an average of 5.9%, 8.0%, 181.4% in comparison with [12], [1] and [9] respectively.