### Q = D case.

read_verilog -icells <<EOT

module top(...);

input CLK;
input EN;
(* init = 24'h555555 *)
output [19:0] Q;
input SRST;
input ARST;
input [1:0] CLR;
input [1:0] SET;

$dff #(.CLK_POLARITY(1'b1), .WIDTH(2)) ff0 (.CLK(CLK), .D(Q[1:0]), .Q(Q[1:0]));
$dffe #(.CLK_POLARITY(1'b1), .EN_POLARITY(1'b1), .WIDTH(2)) ff1 (.CLK(CLK), .EN(EN), .D(Q[3:2]), .Q(Q[3:2]));
$adff #(.CLK_POLARITY(1'b1), .ARST_POLARITY(1'b1), .ARST_VALUE(2'h2), .WIDTH(2)) ff2 (.CLK(CLK), .ARST(ARST), .D(Q[5:4]), .Q(Q[5:4]));
$adffe #(.CLK_POLARITY(1'b1), .EN_POLARITY(1'b0), .ARST_POLARITY(1'b1), .ARST_VALUE(2'h2), .WIDTH(2)) ff3 (.CLK(CLK), .EN(EN), .ARST(ARST), .D(Q[7:6]), .Q(Q[7:6]));
$sdff #(.CLK_POLARITY(1'b1), .SRST_POLARITY(1'b1), .SRST_VALUE(2'h2), .WIDTH(2)) ff4 (.CLK(CLK), .SRST(SRST), .D(Q[9:8]), .Q(Q[9:8]));
$sdffe #(.CLK_POLARITY(1'b1), .EN_POLARITY(1'b1), .SRST_POLARITY(1'b1), .SRST_VALUE(2'h2), .WIDTH(2)) ff5 (.CLK(CLK), .EN(EN), .SRST(SRST), .D(Q[11:10]), .Q(Q[11:10]));
$sdffce #(.CLK_POLARITY(1'b1), .EN_POLARITY(1'b1), .SRST_POLARITY(1'b1), .SRST_VALUE(2'h2), .WIDTH(2)) ff6 (.CLK(CLK), .EN(EN), .SRST(SRST), .D(Q[13:12]), .Q(Q[13:12]));
$dffsr #(.CLK_POLARITY(1'b1), .CLR_POLARITY(1'b1), .SET_POLARITY(1'b0), .WIDTH(2)) ff7 (.CLK(CLK), .SET(SET), .CLR(CLR), .D(Q[15:14]), .Q(Q[15:14]));
$dffsre #(.CLK_POLARITY(1'b1), .EN_POLARITY(1'b0), .CLR_POLARITY(1'b1), .SET_POLARITY(1'b0), .WIDTH(2)) ff8 (.CLK(CLK), .EN(EN), .SET(SET), .CLR(CLR), .D(Q[17:16]), .Q(Q[17:16]));

$dlatch #(.EN_POLARITY(1'b1), .WIDTH(2)) ff9 (.EN(EN), .D(Q[19:18]), .Q(Q[19:18]));
$adlatch #(.EN_POLARITY(1'b0), .ARST_POLARITY(1'b1), .ARST_VALUE(2'h2), .WIDTH(2)) ff10 (.EN(EN), .ARST(ARST), .D(Q[21:20]), .Q(Q[21:20]));
$dlatchsr #(.EN_POLARITY(1'b0), .CLR_POLARITY(1'b1), .SET_POLARITY(1'b0), .WIDTH(2)) ff11 (.EN(EN), .SET(SET), .CLR(CLR), .D(Q[23:22]), .Q(Q[23:22]));

endmodule

EOT

design -save orig

# Equivalence check will fail for unmapped adlatch and dlatchsr due to negative hold hack.
delete top/ff10 top/ff11
equiv_opt -undef -assert -multiclock opt_dff -keepdc

design -load orig
opt_dff -keepdc
select -assert-count 1 t:$and
select -assert-count 3 t:$dffe
select -assert-count 3 t:$dlatch
select -assert-count 3 t:$sr
select -assert-none t:$and t:$dffe t:$dlatch t:$sr %% %n t:* %i

design -load orig
simplemap
opt_dff -keepdc
select -assert-count 2 t:$_AND_
select -assert-count 6 t:$_DFFE_??_
select -assert-count 6 t:$_DLATCH_?_
select -assert-count 6 t:$_SR_??_
select -assert-none t:$_AND_ t:$_DFFE_??_ t:$_DLATCH_?_ t:$_SR_??_ %% %n t:* %i