Abstract. Data dependent circuits are logic circuits specialized to specific input data. They are smaller and faster than the original circuits, although they are not reusable and require circuit generation for each input instance. This study examines data dependent designs for subgraph isomorphism problems, and shows that a simple algorithm is faster than an elaborate algorithm. An algorithm that requires many hardware resources consumes an accordingly longer circuit generation time, which outweighs the performance advantage in execution. 1 Data Dependent Hardware If any input of a logic circuit turns out to be constant, the circuit can be reduced. For example, if any inputs of an AND gate turn out to be zero, the output becomes zero (constant propagation). This reduction can be applied recursively, consequently reducing the logic scale of the circuit. The derived circuit would operate at a higher frequency than the original, because the logic depth and wiring delay would also be red...