read_verilog memdemo.v
prep -top memdemo; memory; opt

cd memdemo
select -set outstage y %ci2:+$dff[Q,D] %ci*:-$mux[S]:-$dff
select -set selstage y %ci2:+$dff[Q,D] %ci*:-$dff @outstage %d
select -set scramble mem* %ci2 %ci*:-$dff mem* %d @selstage %d
submod -name scramble @scramble
submod -name outstage @outstage
submod -name selstage @selstage

cd ..
show -format dot -prefix submod_00 memdemo
show -format dot -prefix submod_01 scramble
show -format dot -prefix submod_02 outstage
show -format dot -prefix submod_03 selstage