Electronic design tools using non-synthesizable circuit elements

A computer software product, comprising a non-transitory computer-readable medium in which program instructions are stored, which instructions, when read by a computer, cause the computer to receive hardware description language (HDL) code defining a design of a circuit, and to append a non-synthesizable input having a unique identifier to the HDL code that specifies a physical input of the circuit, and for each of a plurality of physical components in the circuit to which a signal from the physical input is to propagate, to append corresponding non-synthesizable components, having respective identifiers assigned responsively to the unique identifier of the non-synthesizable input, to the HDL code that specifies the physical components,

• wherein the instructions cause the computer to verify the design, using the assigned identifiers, by simulating operation of the circuit using the HDL code, including both the physical and non-synthesizable inputs and components, and after verifying the design, to submit the HDL code, including both the physical and non-synthesizable inputs and components, to a netlist synthesis tool, which automatically generates a netlist of the circuit comprising the physical inputs and components while omitting the non-synthesizable inputs and components.