A method of optimizing timing performance of an IC design expressed as a graph that includes several nodes representing IC components is provided. The method identifies several paths in the graph. Each path starts from a timed source node and ends to a timed target node. Each path includes several clocked elements and several computational elements. The method optimizes the timing performance of the IC design by skewing clock signals to one or more clocked elements in a set of paths to satisfy timing constraints. The method identifies a path that includes a set of edge-triggered clocked elements and does not satisfy the set of timing constraints. The method replaces each edge-triggered clocked element in the identified path with a level-sensitive clocked element and optimizes the timing performance of the IC design by skewing clock signals one or more clocked element in the identified path.