Performance Improvement of Physical Retiming with Shortcut Insertion

Retiming is a well known method for improving the performance of sequential circuits. However, maximum cycle ratio (MCR) is one of the most serious restrictions to be considered by retiming-based techniques. As MCR is proportional to the critical cycle delay, finding shortcut paths to reduce the length of critical cycle can improve the circuit performance. In this paper, Shannon decomposition is used iteratively to insert shortcuts and reduce critical cycles delay. Reducing MCR can lead to better physical retiming results due to available placement information. Our experimental results show more than 16% improvement in retiming gained performance with the area overhead of about 3%, on average.