miter - automatically create a miter circuit

    miter -equiv [options] gold_name gate_name miter_name

Creates a miter circuit for equivalence checking. The gold- and gate- modules
must have the same interfaces. The miter circuit will have all inputs of the
two source modules, prefixed with 'in_'. The miter circuit has a 'trigger'
output that goes high if an output mismatch between the two source modules is

        a undef (x) bit in the gold module output will match any value in
        the gate module output.

        also route the gold- and gate-outputs to 'gold_*' and 'gate_*' outputs
        on the miter circuit.

        also create a cmp_* output for each gold/gate output pair.

        also create an 'assert' cell that checks if trigger is always low.

        call 'flatten -wb; opt_expr -keepdc -undriven;;' on the miter circuit.

    miter -assert [options] module [miter_name]

Creates a miter circuit for property checking. All input ports are kept,
output ports are discarded. An additional output 'trigger' is created that
goes high when an assert is violated. Without a miter_name, the existing
module is modified.

        keep module output ports.

        call 'flatten -wb; opt_expr -keepdc -undriven;;' on the miter circuit.