User designs are assigned to a category for each design goal associated with the user design. Each category represents the difficulty of satisfying a design goal. Optimization phases are tailored to different combinations of categories and are selected according to the categories assigned to the user design. A ranking of the relative difficulty of the design goals is determined from the categories associated with the user design. Parameters of an optimization phase can be modified in accordance with this ranking to focus optimization efforts on specific design goals. The parameters may be weights of a cost function used by the optimization phase to evaluate alternative configurations of the user design. The user design can be re-classified into an additional category if the results of the optimization phase do not satisfy design goals, and additional optimization phases are selected based on this re-classification to further optimize the user design.