1 files changed, 45 insertions, 0 deletions
diff --git a/tests/opt/opt_dff_clk.ys b/tests/opt/opt_dff_clk.ys
new file mode 100644
index 000000000..f3aefa406
--- /dev/null
+++ b/tests/opt/opt_dff_clk.ys
@@ -0,0 +1,45 @@
+### Never-toggling CLK removal.
+
+read_verilog -icells <<EOT
+
+module top(...);
+
+input EN;
+input [1:0] D;
+(* init = 18'h15555 *)
+output [17:0] Q;
+input SRST;
+input ARST;
+input [1:0] CLR;
+input [1:0] SET;
+
+$dff #(.CLK_POLARITY(1'b1), .WIDTH(2)) ff0 (.CLK(1'b0), .D(D), .Q(Q[1:0]));
+$dffe #(.CLK_POLARITY(1'b1), .EN_POLARITY(1'b1), .WIDTH(2)) ff1 (.CLK(1'b1), .EN(EN), .D(D), .Q(Q[3:2]));
+$adff #(.CLK_POLARITY(1'b1), .ARST_POLARITY(1'b1), .ARST_VALUE(2'h2), .WIDTH(2)) ff2 (.CLK(1'bx), .ARST(ARST), .D(D), .Q(Q[5:4]));
+$adffe #(.CLK_POLARITY(1'b1), .EN_POLARITY(1'b0), .ARST_POLARITY(1'b1), .ARST_VALUE(2'h2), .WIDTH(2)) ff3 (.CLK(1'b0), .EN(EN), .ARST(ARST), .D(D), .Q(Q[7:6]));
+$sdff #(.CLK_POLARITY(1'b1), .SRST_POLARITY(1'b1), .SRST_VALUE(2'h2), .WIDTH(2)) ff4 (.CLK(1'b1), .SRST(SRST), .D(D), .Q(Q[9:8]));
+$sdffe #(.CLK_POLARITY(1'b1), .EN_POLARITY(1'b1), .SRST_POLARITY(1'b1), .SRST_VALUE(2'h2), .WIDTH(2)) ff5 (.CLK(1'bx), .EN(EN), .SRST(SRST), .D(D), .Q(Q[11:10]));
+$sdffce #(.CLK_POLARITY(1'b1), .EN_POLARITY(1'b1), .SRST_POLARITY(1'b1), .SRST_VALUE(2'h2), .WIDTH(2)) ff6 (.CLK(1'bx), .EN(EN), .SRST(SRST), .D(D), .Q(Q[13:12]));
+$dffsr #(.CLK_POLARITY(1'b1), .CLR_POLARITY(1'b1), .SET_POLARITY(1'b0), .WIDTH(2)) ff7 (.CLK(1'b1), .SET(SET), .CLR(CLR), .D(D), .Q(Q[15:14]));
+$dffsre #(.CLK_POLARITY(1'b1), .EN_POLARITY(1'b0), .CLR_POLARITY(1'b1), .SET_POLARITY(1'b0), .WIDTH(2)) ff8 (.CLK(1'bx), .EN(EN), .SET(SET), .CLR(CLR), .D(D), .Q(Q[17:16]));
+
+endmodule
+
+EOT
+
+design -save orig
+
+equiv_opt -undef -assert -multiclock opt_dff -keepdc
+design -load postopt
+select -assert-count 2 t:$dlatch
+select -assert-count 2 t:$sr
+select -assert-none t:$dlatch t:$sr %% %n t:* %i
+
+design -load orig
+simplemap
+
+equiv_opt -undef -assert -multiclock opt_dff -keepdc
+design -load postopt
+select -assert-count 4 t:$_DLATCH_?_
+select -assert-count 4 t:$_SR_??_
+select -assert-none t:$_DLATCH_?_ t:$_SR_??_ %% %n t:* %i