Is redundancy necessary to reduce delay?

The question of whether single stuck-at-fault redundancies are necessary to increase performance or whether they are only an unnecessary by-product of performance optimization is addressed. A constructive resolution of this question is given in the form of an algorithm that takes as input a combinational circuit and returns an irredundant circuit that is as fast. The utility of this algorithm is demonstrated on a well-known circuit, the carry-skip adder, and a novel irredundant design of that adder is presented. As the algorithm may either increase or decrease circuit area, the authors leave unresolved the question as to whether every circuit has an irredundant circuit that is at least as fast and is of equal or lesser area