Systems and methods relate to cell placement methodologies for improving length of diffusion of transistors. For example, a first transistor with a first diffusion node which is bounded by a first diffusion cut is identified in a transistor level layout. The first diffusion cut is replaced with a first floating gate, and a first filler cell with a first filler diffusion region is added to extend a length of diffusion of the first diffusion node. Increasing the length of diffusion leads to improving drive strength and performance of the first transistor.