yosys/tests/opt/opt_dff_mux.ys

### CE and SRST matching.

read_verilog -icells <<EOT

module top(...);

input CLK;
input NE, NS;
input EN;
output [17:0] Q;
input [23:0] D;
input SRST;
input ARST;
input [1:0] CLR;
input [1:0] SET;

$dff #(.CLK_POLARITY(1'b1), .WIDTH(2)) ff0 (.CLK(CLK), .D(NS ? 2'h2 : NE ? D[1:0] : Q[1:0]), .Q(Q[1:0]));
$dffe #(.CLK_POLARITY(1'b1), .EN_POLARITY(1'b1), .WIDTH(2)) ff1 (.CLK(CLK), .EN(EN), .D(NS ? 2'h2 : NE ? D[3:2] : 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(NS ? 2'h2 : NE ? D[5:4] : 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(NS ? 2'h2 : NE ? D[7:6] : 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(NS ? 2'h2 : NE ? D[9:8] : 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(NS ? 2'h2 : NE ? D[11:10] : 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(NS ? 2'h2 : NE ? D[13:12] : 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(NS ? 2'h2 : NE ? D[15:14] : 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(NS ? 2'h2 : NE ? D[17:16] : Q[17:16]), .Q(Q[17:16]));

endmodule

EOT

design -save orig

equiv_opt -undef -assert -multiclock opt_dff -keepdc
design -load postopt
clean
select -assert-count 0 t:$dff
select -assert-count 0 t:$dffe
select -assert-count 0 t:$adff
select -assert-count 2 t:$adffe
select -assert-count 0 t:$dffsr
select -assert-count 2 t:$dffsre
select -assert-count 0 t:$sdff
select -assert-count 3 t:$sdffe
select -assert-count 2 t:$sdffce

design -load orig

equiv_opt -undef -assert -multiclock opt_dff -nodffe -nosdff
design -load postopt
clean
select -assert-count 1 t:$dff
select -assert-count 1 t:$dffe
select -assert-count 1 t:$adff
select -assert-count 1 t:$adffe
select -assert-count 1 t:$dffsr
select -assert-count 1 t:$dffsre
select -assert-count 1 t:$sdff
select -assert-count 1 t:$sdffe
select -assert-count 1 t:$sdffce
equiv_opt -undef -assert -multiclock opt_dff -nodffe
design -load postopt
clean
select -assert-count 0 t:$dff
select -assert-count 0 t:$dffe
select -assert-count 1 t:$adff
select -assert-count 1 t:$adffe
select -assert-count 1 t:$dffsr
select -assert-count 1 t:$dffsre
select -assert-count 2 t:$sdff
select -assert-count 1 t:$sdffe
select -assert-count 2 t:$sdffce

design -load orig

equiv_opt -undef -assert -multiclock opt_dff -nosdff
design -load postopt
clean
select -assert-count 0 t:$dff
select -assert-count 2 t:$dffe
select -assert-count 0 t:$adff
select -assert-count 2 t:$adffe
select -assert-count 0 t:$dffsr
select -assert-count 2 t:$dffsre
select -assert-count 0 t:$sdff
select -assert-count 2 t:$sdffe
select -assert-count 1 t:$sdffce