Formal verification of candidate solutions for post-synthesis evolutionary optimization in evolvable hardware

We propose to utilize a formal verification algorithm to reduce the fitness evaluation time for evolutionary post-synthesis optimization in evolvable hardware. The proposed method assumes that a fully functional digital circuit is available. A post-synthesis optimization is then conducted using Cartesian Genetic Programming (CGP) which utilizes a satisfiability problem solver to decide whether a candidate solution is functionally correct or not. It is demonstrated that the method can optimize digital circuits of tens of inputs and thousands of gates. Furthermore, the number of gates was reduced for the LGSynth93 benchmark circuits by 37.8% on average with respect to results of the conventional SIS tool.