A utility includes a design-for-manufacturing (DFM) checker configured to check layout patterns of an integrated circuit, and a layout change instruction generator configured to generate a layout change instruction based on a result generated by the DFM checker. The DFM checker and the layout change instruction generator are embodied on a non-transitory storage media. The layout change instruction specifies an identifier of a layout pattern among the layout patterns, and a respective layout change to be performed on the layout pattern.