%Warning-UNOPT: t/t_unopt_converge.v:18: Signal unoptimizable: Feedback to public clock or circular logic: x
%Warning-UNOPT: Use "/* verilator lint_off UNOPT */" and lint_on around source to disable this message.
%Warning-UNOPT:      Example path: t/t_unopt_converge.v:18:  x
%Warning-UNOPT:      Example path: t/t_unopt_converge.v:21:  ALWAYS
%Warning-UNOPT:      Example path: t/t_unopt_converge.v:18:  x
%Error: Exiting due to