On the optimization power of retiming and resynthesis transformations

Retiming and resynthesis transformations can be used for optimizing the area, power, and delay of sequential circuits. Even though this technique has been known for more than a decade, its exact optimization capability has not been formally established. We show that retiming and resynthesis can exactly implement 1-step equivalent state transition graph transformations. This result is the strongest to date. We also show how the notions of retiming and resynthesis can be moderately extended to achieve more powerful state transition graph transformations. Our work will provide theoretical foundation for practical retiming and resynthesis based optimization and verification.