1. A computer-performed method performed by a general-purpose computer system that modifies a netlist describing a logic design, the method comprising: reading, by a computer system, a simulation output from a simulation performed on the logic design, wherein the simulation output contains states having values dependent on symbolic values introduced as inputs to the logic design in the simulation and specified by including the symbolic values in the simulation output; determining, within the computer system, that the symbolic values reveal relationships or behaviors within the logic design that indicate that the logic design can be simplified or reduced; and modifying responsive to the determining and by the computer system, the netlist to simplify or reduce the netlist in accordance with a result of the determining.