Systems and techniques are described for optimizing a circuit design. Specifically, gate sizes in the circuit design are optimized by iteratively performing a set of operations that include, but are not limited to: selecting a portion of the circuit design (e.g., according to a reverse-levelized processing order), selecting an input-to-output arc of a driver gate in the portion of the circuit design, selecting gates in the portion of the circuit design for optimization, modeling a gate optimization problem based on the selected input-to-output arc of the driver gate and the selected gates, solving the gate optimization problem to obtain a solution using one or more solvers, and discretizing the solution. Discretizing the solution involves identifying library cells that exactly or closely match the gate sizes specified in the solution. These library cells can then be used to model other gate optimization problems in the current or subsequent iterations.