Phase shifting generates features in a printed features layer, such as a printed circuit, that are narrower than the features on a fabrication layout, such as a mask, projected onto the printed features layer using the same optical system without phase shifting. Techniques for forming a fabrication layout for a physical design layout having critical features employing phase shifting include techniques for providing a layout for shifters. The techniques include establishing placement of multiple pairs of shifters for a set of critical features. A critical feature employs phase shifting. The set of critical features constitutes a subset of all critical features in a layout. After establishing placement of the pairs of shifters, phase information for the shifters associated with the set of critical features is assigned. This and related techniques expedite resolving phase-shift conflicts in fabrication layouts for phase-shifted features. Complex designs can lead to phase-shift conflicts among shifters in the fabrication layout. According to these techniques, a conflict that cannot be resolved by a fabrication design process is passed to the design process earlier than in a conventional processes, saving valuable time in the fabrication process for printed circuits.