read_verilog adffs.v
proc
dff2dffe
synth_ice40
select -assert-count 2 t:SB_DFFR
select -assert-count 1 t:SB_DFFE
select -assert-count 4 t:SB_LUT4
#select -assert-none t:SB_LUT4 t:SB_DFFR t:SB_DFFE t:$_DFFSR_NPP_ t:$_DFFSR_PPP_ %% t:* %D
write_verilog adffs_synth.v