A method involving identifying a pattern for an overall target cut mask to be used in patterning line-type features that includes a target non-rectangular opening feature having an inner, concave corner, decomposing the overall target cut mask pattern into first and second sub-target patterns, wherein the first sub-target pattern comprises a first rectangular-shaped opening feature corresponding to a first portion, but not all, of the target non-rectangular opening feature and the second sub-target pattern comprises a second rectangular-shaped opening feature corresponding to a second portion, but not all, of the target non-rectangular opening feature, the first and second openings overlapping adjacent the inner, concave corner, and generating first and second sets of mask data corresponding to the first and second sub-target patterns, wherein at least one of the first and second sets of mask data is generated based upon an identified contact-to-end-of-cut-line spacing rule.