Incremental placement for timing optimization

An incremental timing driven placement algorithm is presented. We introduce a fast path-based analytical approach for timing improvement. Our method achieves timing optimization by reducing the enclosing bounding boxes of selected nets on critical paths. Furthermore, this technique tries to minimize modifications to the initial placement while improving the delay of the circuit incrementally. Two contributions of this work are 1) efficient conversion of a path-based timing minimization problem to a geometric net-constraint problem and 2) minimal modification of a placement to improve timing. Our technique can take an initial placement from any algorithm and improve timing iteratively. The experiments show that the proposed approach is very efficient.