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combloop_finder usage

Combinational logic loop is sticky problem, but you can find it by combloop_finder easily.

python combloop_finder.py xxxx.v

if there is a combinational loop in your design, combloop_finder raise error and specify loop occurrence place.

ex.

module TOP(CLK, RST);
  input CLK,RST;
  wire wire1,wire2,wire3;

  assign wire1 = wire2;
  assign wire2 = !wire3;
  assign wire3 = wire1;

endmodule

Output:

CombLoopException: Combinational loop is found @TOP.wire3