A method of assigning phases to shifters on a layout is provided. The method includes creating a link between any two shifters within a predetermined distance from each other. In one embodiment, the predetermined distance is larger than a minimum feature size on the layout, and smaller than a combined minimum pitch and regulator width. A weight can be assigned to each created link. Phases can be assigned to the shifters, wherein if a phase-shift conflict exists on the layout, then one or more links can be broken based on their weight.