Structured ASICs that are equivalent to FPGA logic designs are produced by making use of a library of known structured ASIC equivalents to FPGA logic functions. Such a library is expanded by a process that searches new FPGA logic designs for logic functions that either do not already have structured ASIC equivalents in the library or for which possibly improved structured ASIC equivalents can now be devised. The new and/or improved structured ASIC equivalents are added to the library, preferably with version information in the case of FPGA logic functions for which more than one structured ASIC equivalent is known.