tribuf - infer tri-state buffers

yosys> help tribuf
tribuf [options] [selection]
This pass transforms $mux cells with 'z' inputs to tristate buffers.
merge multiple tri-state buffers driving the same net
into a single buffer.
convert tri-state buffers that do not drive output ports
to non-tristate logic. this option implies -merge.
convert all tri-state buffers to non-tristate logic and
add a formal assertion that no two buffers are driving the
same net simultaneously. this option implies -merge.