A computer implemented method, apparatus, and computer usable program product for modifying a circuit design are provided in the illustrative embodiments. A set of candidate areas within the circuit design is identified for making a change to the circuit design. A cost associated with each candidate area in the set of candidate areas is determined to form a set of costs. The cost associated with a candidate area is the cost of making the change to the circuit design in the candidate area. Using the set of costs, a candidate area is selected from the set of candidate areas in which to make the change to the circuit design.