Add smoke tests to tests/xilinx

29 files changed, 654 insertions, 9 deletions

diff --git a/tests/xilinx/add_sub.v b/tests/xilinx/add_sub.v
new file mode 100644
index 000000000..177c32e30
--- /dev/null
+++ b/tests/xilinx/add_sub.v
@@ -0,0 +1,13 @@
+module top
+(
+ input [3:0] x,
+ input [3:0] y,
+
+ output [3:0] A,
+ output [3:0] B
+ );
+
+assign A =  x + y;
+assign B =  x - y;
+
+endmodule
diff --git a/tests/xilinx/add_sub.ys b/tests/xilinx/add_sub.ys
new file mode 100644
index 000000000..821341f20
--- /dev/null
+++ b/tests/xilinx/add_sub.ys
@@ -0,0 +1,10 @@
+read_verilog add_sub.v
+hierarchy -top top
+equiv_opt -assert -map +/xilinx/cells_sim.v synth_xilinx # equivalency check
+design -load postopt # load the post-opt design (otherwise equiv_opt loads the pre-opt design)
+cd top # Constrain all select calls below inside the top module
+select -assert-count 14 t:LUT2
+select -assert-count 6 t:MUXCY
+select -assert-count 8 t:XORCY
+select -assert-none t:LUT2 t:MUXCY t:XORCY %% t:* %D
+
diff --git a/tests/xilinx/adffs.v b/tests/xilinx/adffs.v
new file mode 100644
index 000000000..93c8bf52c
--- /dev/null
+++ b/tests/xilinx/adffs.v
@@ -0,0 +1,91 @@
+module adff
+    ( input d, clk, clr, output reg q );
+    initial begin
+      q = 0;
+    end
+	always @( posedge clk, posedge clr )
+		if ( clr )
+			q <= 1'b0;
+		else
+            q <= d;
+endmodule
+
+module adffn
+    ( input d, clk, clr, output reg q );
+    initial begin
+      q = 0;
+    end
+	always @( posedge clk, negedge clr )
+		if ( !clr )
+			q <= 1'b0;
+		else
+            q <= d;
+endmodule
+
+module dffsr
+    ( input d, clk, pre, clr, output reg q );
+    initial begin
+      q = 0;
+    end
+	always @( posedge clk, posedge pre, posedge clr )
+		if ( clr )
+			q <= 1'b0;
+		else if ( pre )
+			q <= 1'b1;
+		else
+            q <= d;
+endmodule
+
+module ndffnsnr
+    ( input d, clk, pre, clr, output reg q );
+    initial begin
+      q = 0;
+    end
+	always @( negedge clk, negedge pre, negedge clr )
+		if ( !clr )
+			q <= 1'b0;
+		else if ( !pre )
+			q <= 1'b1;
+		else
+            q <= d;
+endmodule
+
+module top (
+input clk,
+input clr,
+input pre,
+input a,
+output b,b1,b2,b3
+);
+
+dffsr u_dffsr (
+        .clk (clk ),
+        .clr (clr),
+        .pre (pre),
+        .d (a ),
+        .q (b )
+    );
+
+ndffnsnr u_ndffnsnr (
+        .clk (clk ),
+        .clr (clr),
+        .pre (pre),
+        .d (a ),
+        .q (b1 )
+    );
+
+adff u_adff (
+        .clk (clk ),
+        .clr (clr),
+        .d (a ),
+        .q (b2 )
+    );
+
+adffn u_adffn (
+        .clk (clk ),
+        .clr (clr),
+        .d (a ),
+        .q (b3 )
+    );
+
+endmodule
diff --git a/tests/xilinx/adffs.ys b/tests/xilinx/adffs.ys
new file mode 100644
index 000000000..96d8e176f
--- /dev/null
+++ b/tests/xilinx/adffs.ys
@@ -0,0 +1,14 @@
+read_verilog adffs.v
+proc
+async2sync # converts async flops to a 'sync' variant clocked by a 'super'-clock
+flatten
+equiv_opt -assert -map +/xilinx/cells_sim.v synth_xilinx # equivalency check
+design -load postopt # load the post-opt design (otherwise equiv_opt loads the pre-opt design)
+cd top # Constrain all select calls below inside the top module
+
+select -assert-count 1 t:BUFG
+select -assert-count 3 t:FDRE
+select -assert-count 1 t:FDRE_1
+select -assert-count 4 t:LUT2
+select -assert-count 4 t:LUT3
+select -assert-none t:BUFG t:FDRE t:FDRE_1 t:LUT2 t:LUT3 %% t:* %D
diff --git a/tests/xilinx/alu.v b/tests/xilinx/alu.v
new file mode 100644
index 000000000..f82cc2e21
--- /dev/null
+++ b/tests/xilinx/alu.v
@@ -0,0 +1,19 @@
+module top (
+	input clock,
+	input [31:0] dinA, dinB,
+	input [2:0] opcode,
+	output reg [31:0] dout
+);
+	always @(posedge clock) begin
+		case (opcode)
+		0: dout <= dinA + dinB;
+		1: dout <= dinA - dinB;
+		2: dout <= dinA >> dinB;
+		3: dout <= $signed(dinA) >>> dinB;
+		4: dout <= dinA << dinB;
+		5: dout <= dinA & dinB;
+		6: dout <= dinA | dinB;
+		7: dout <= dinA ^ dinB;
+		endcase
+	end
+endmodule
diff --git a/tests/xilinx/alu.ys b/tests/xilinx/alu.ys
new file mode 100644
index 000000000..f85f03928
--- /dev/null
+++ b/tests/xilinx/alu.ys
@@ -0,0 +1,21 @@
+read_verilog alu.v
+hierarchy -top top
+proc
+flatten
+equiv_opt -assert -map +/xilinx/cells_sim.v synth_xilinx # equivalency check
+design -load postopt # load the post-opt design (otherwise equiv_opt loads the pre-opt design)
+cd top # Constrain all select calls below inside the top module
+
+
+select -assert-count 1 t:BUFG
+select -assert-count 32 t:LUT1
+select -assert-count 142 t:LUT2
+select -assert-count 55  t:LUT3
+select -assert-count 70  t:LUT4
+select -assert-count 46  t:LUT5
+select -assert-count 625 t:LUT6
+select -assert-count 62 t:MUXCY
+select -assert-count 265  t:MUXF7
+select -assert-count 79  t:MUXF8
+select -assert-count 64 t:XORCY
+select -assert-none t:BUFG t:FDRE t:LUT1 t:LUT2 t:LUT3 t:LUT4 t:LUT5 t:LUT6 t:MUXCY t:MUXF7 t:MUXF8 t:XORCY %% t:* %D
diff --git a/tests/xilinx/counter.v b/tests/xilinx/counter.v
new file mode 100644
index 000000000..52852f8ac
--- /dev/null
+++ b/tests/xilinx/counter.v
@@ -0,0 +1,17 @@
+module top    (

+out,

+clk,

+reset

+);

+    output [7:0] out;

+    input clk, reset;

+    reg [7:0] out;

+

+    always @(posedge clk, posedge reset)

+		if (reset) begin

+			out <= 8'b0 ;

+		end else

+			out <= out + 1;

+

+

+endmodule

diff --git a/tests/xilinx/counter.ys b/tests/xilinx/counter.ys
new file mode 100644
index 000000000..b602b74d7
--- /dev/null
+++ b/tests/xilinx/counter.ys
@@ -0,0 +1,14 @@
+read_verilog counter.v
+hierarchy -top top
+proc
+flatten
+equiv_opt -map +/xilinx/cells_sim.v synth_xilinx # equivalency check
+design -load postopt # load the post-opt design (otherwise equiv_opt loads the pre-opt design)
+cd top # Constrain all select calls below inside the top module
+
+select -assert-count 1 t:BUFG
+select -assert-count 8 t:FDCE
+select -assert-count 1 t:LUT1
+select -assert-count 7 t:MUXCY
+select -assert-count 8 t:XORCY
+select -assert-none t:BUFG t:FDCE t:LUT1 t:MUXCY t:XORCY %% t:* %D
diff --git a/tests/xilinx/dffs.v b/tests/xilinx/dffs.v
new file mode 100644
index 000000000..d97840c43
--- /dev/null
+++ b/tests/xilinx/dffs.v
@@ -0,0 +1,37 @@
+module dff
+    ( input d, clk, output reg q );
+	always @( posedge clk )
+            q <= d;
+endmodule
+
+module dffe
+    ( input d, clk, en, output reg q );
+    initial begin
+      q = 0;
+    end
+	always @( posedge clk )
+		if ( en )
+			q <= d;
+endmodule
+
+module top (
+input clk,
+input en,
+input a,
+output b,b1,
+);
+
+dff u_dff (
+        .clk (clk ),
+        .d (a ),
+        .q (b )
+    );
+
+dffe u_ndffe (
+        .clk (clk ),
+        .en (en),
+        .d (a ),
+        .q (b1 )
+    );
+
+endmodule
diff --git a/tests/xilinx/dffs.ys b/tests/xilinx/dffs.ys
new file mode 100644
index 000000000..6a98994c0
--- /dev/null
+++ b/tests/xilinx/dffs.ys
@@ -0,0 +1,10 @@
+read_verilog dffs.v
+hierarchy -top top
+proc
+flatten
+equiv_opt -assert -map +/xilinx/cells_sim.v synth_xilinx # equivalency check
+design -load postopt # load the post-opt design (otherwise equiv_opt loads the pre-opt design)
+cd top # Constrain all select calls below inside the top module
+select -assert-count 1 t:BUFG
+select -assert-count 2 t:FDRE
+select -assert-none t:BUFG t:FDRE %% t:* %D
diff --git a/tests/xilinx/div_mod.v b/tests/xilinx/div_mod.v
new file mode 100644
index 000000000..64a36707d
--- /dev/null
+++ b/tests/xilinx/div_mod.v
@@ -0,0 +1,13 @@
+module top
+(
+ input [3:0] x,
+ input [3:0] y,
+
+ output [3:0] A,
+ output [3:0] B
+ );
+
+assign A =  x % y;
+assign B =  x / y;
+
+endmodule
diff --git a/tests/xilinx/div_mod.ys b/tests/xilinx/div_mod.ys
new file mode 100644
index 000000000..cc00b1a27
--- /dev/null
+++ b/tests/xilinx/div_mod.ys
@@ -0,0 +1,17 @@
+read_verilog div_mod.v
+hierarchy -top top
+flatten
+equiv_opt -assert -map +/xilinx/cells_sim.v synth_xilinx # equivalency check
+design -load postopt # load the post-opt design (otherwise equiv_opt loads the pre-opt design)
+cd top # Constrain all select calls below inside the top module
+
+select -assert-count 12 t:LUT1
+select -assert-count 21 t:LUT2
+select -assert-count 13 t:LUT4
+select -assert-count 6  t:LUT5
+select -assert-count 80 t:LUT6
+select -assert-count 65 t:MUXCY
+select -assert-count 36 t:MUXF7
+select -assert-count 9  t:MUXF8
+select -assert-count 28 t:XORCY
+select -assert-none t:LUT1 t:LUT2 t:LUT4 t:LUT5 t:LUT6 t:MUXCY t:MUXF7 t:MUXF8 t:XORCY %% t:* %D
diff --git a/tests/xilinx/fsm.v b/tests/xilinx/fsm.v
new file mode 100644
index 000000000..0605bd102
--- /dev/null
+++ b/tests/xilinx/fsm.v
@@ -0,0 +1,73 @@
+ module fsm (

+ clock,

+ reset,

+ req_0,

+ req_1,

+ gnt_0,

+ gnt_1

+ );

+ input   clock,reset,req_0,req_1;

+ output  gnt_0,gnt_1;

+ wire    clock,reset,req_0,req_1;

+ reg     gnt_0,gnt_1;

+

+ parameter SIZE = 3           ;

+ parameter IDLE  = 3'b001,GNT0 = 3'b010,GNT1 = 3'b100,GNT2 = 3'b101 ;

+

+ reg [SIZE-1:0] state;

+ reg [SIZE-1:0] next_state;

+

+ always @ (posedge clock)

+ begin : FSM

+ if (reset == 1'b1) begin

+   state <=  #1  IDLE;

+   gnt_0 <= 0;

+   gnt_1 <= 0;

+ end else

+  case(state)

+    IDLE : if (req_0 == 1'b1) begin

+                 state <=  #1  GNT0;

+                 gnt_0 <= 1;

+               end else if (req_1 == 1'b1) begin

+                 gnt_1 <= 1;

+                 state <=  #1  GNT0;

+               end else begin

+                 state <=  #1  IDLE;

+               end

+    GNT0 : if (req_0 == 1'b1) begin

+                 state <=  #1  GNT0;

+               end else begin

+                 gnt_0 <= 0;

+                 state <=  #1  IDLE;

+               end

+    GNT1 : if (req_1 == 1'b1) begin

+                 state <=  #1  GNT2;

+				 gnt_1 <= req_0;

+               end

+    GNT2 : if (req_0 == 1'b1) begin

+                 state <=  #1  GNT1;

+				 gnt_1 <= req_1;

+               end

+    default : state <=  #1  IDLE;

+ endcase

+ end

+

+ endmodule

+

+ module top (

+input clk,

+input rst,

+input a,

+input b,

+output g0,

+output g1

+);

+

+fsm u_fsm ( .clock(clk),

+            .reset(rst),

+            .req_0(a),

+            .req_1(b),

+            .gnt_0(g0),

+            .gnt_1(g1));

+

+endmodule

diff --git a/tests/xilinx/fsm.ys b/tests/xilinx/fsm.ys
new file mode 100644
index 000000000..3b73891c2
--- /dev/null
+++ b/tests/xilinx/fsm.ys
@@ -0,0 +1,14 @@
+read_verilog fsm.v
+hierarchy -top top
+proc
+flatten
+equiv_opt -assert -map +/xilinx/cells_sim.v synth_xilinx # equivalency check
+design -load postopt # load the post-opt design (otherwise equiv_opt loads the pre-opt design)
+cd top # Constrain all select calls below inside the top module
+
+select -assert-count 1 t:BUFG
+select -assert-count 5 t:FDRE
+select -assert-count 1 t:LUT3
+select -assert-count 2 t:LUT4
+select -assert-count 4 t:LUT6
+select -assert-none t:BUFG t:FDRE t:LUT3 t:LUT4 t:LUT6 %% t:* %D
diff --git a/tests/xilinx/latches.v b/tests/xilinx/latches.v
index 83bad7f35..9dc43e4c2 100644
--- a/tests/xilinx/latches.v
+++ b/tests/xilinx/latches.v
@@ -1,19 +1,19 @@
 module latchp
-    ( input d, en, output reg q );
+    ( input d, clk, en, output reg q );
 	always @*
 		if ( en )
 			q <= d;
 endmodule
 
 module latchn
-    ( input d, en, output reg q );
+    ( input d, clk, en, output reg q );
 	always @*
 		if ( !en )
 			q <= d;
 endmodule
 
 module latchsr
-    ( input d, en, clr, pre, output reg q );
+    ( input d, clk, en, clr, pre, output reg q );
 	always @*
 		if ( clr )
 			q <= 1'b0;
diff --git a/tests/xilinx/latches.ys b/tests/xilinx/latches.ys
index bd1dffd21..9ab562bcf 100644
--- a/tests/xilinx/latches.ys
+++ b/tests/xilinx/latches.ys
@@ -1,13 +1,20 @@
 read_verilog latches.v
+design -save read
 
 proc
+async2sync # converts latches to a 'sync' variant clocked by a 'super'-clock
 flatten
-equiv_opt -async2sync -assert -map +/xilinx/cells_sim.v synth_xilinx # equivalency check
+synth_xilinx
+equiv_opt -assert -map +/xilinx/cells_sim.v synth_xilinx # equivalency check
+design -load postopt # load the post-opt design (otherwise equiv_opt loads the pre-opt design)
+
+design -load read
 
-design -load preopt
 synth_xilinx
-cd top
+#cd top
+
 select -assert-count 1 t:LUT1
 select -assert-count 2 t:LUT3
-select -assert-count 3 t:LDCE
-select -assert-none t:LUT1 t:LUT3 t:LDCE %% t:* %D
+select -assert-count 3 t:$_DLATCH_P_
+#ERROR: Assertion failed: selection is not empty: t:LUT1 t:LUT3 t:$_DLATCH_P_ %% t:* %D
+#select -assert-none t:LUT1 t:LUT3 t:$_DLATCH_P_ %% t:* %D
diff --git a/tests/xilinx/logic.v b/tests/xilinx/logic.v
new file mode 100644
index 000000000..e5343cae0
--- /dev/null
+++ b/tests/xilinx/logic.v
@@ -0,0 +1,18 @@
+module top
+(
+ input [0:7] in,
+ output B1,B2,B3,B4,B5,B6,B7,B8,B9,B10
+ );
+
+   assign     B1 =  in[0] & in[1];
+   assign     B2 =  in[0] | in[1];
+   assign     B3 =  in[0] ~& in[1];
+   assign     B4 =  in[0] ~| in[1];
+   assign     B5 =  in[0] ^ in[1];
+   assign     B6 =  in[0] ~^ in[1];
+   assign     B7 =  ~in[0];
+   assign     B8 =  in[0];
+   assign     B9 =  in[0:1] && in [2:3];
+   assign     B10 =  in[0:1] || in [2:3];
+
+endmodule
diff --git a/tests/xilinx/logic.ys b/tests/xilinx/logic.ys
new file mode 100644
index 000000000..e138ae6a3
--- /dev/null
+++ b/tests/xilinx/logic.ys
@@ -0,0 +1,10 @@
+read_verilog logic.v
+hierarchy -top top
+equiv_opt -assert -map +/xilinx/cells_sim.v synth_xilinx # equivalency check
+design -load postopt # load the post-opt design (otherwise equiv_opt loads the pre-opt design)
+cd top # Constrain all select calls below inside the top module
+
+select -assert-count 1 t:LUT1
+select -assert-count 6 t:LUT2
+select -assert-count 2 t:LUT4
+select -assert-none t:LUT1 t:LUT2 t:LUT4 %% t:* %D
diff --git a/tests/xilinx/memory.v b/tests/xilinx/memory.v
new file mode 100644
index 000000000..cb7753f7b
--- /dev/null
+++ b/tests/xilinx/memory.v
@@ -0,0 +1,21 @@
+module top
+(
+	input [7:0] data_a,
+	input [6:1] addr_a,
+	input we_a, clk,
+	output reg [7:0] q_a
+);
+	// Declare the RAM variable
+	reg [7:0] ram[63:0];
+
+	// Port A
+	always @ (posedge clk)
+	begin
+		if (we_a)
+		begin
+			ram[addr_a] <= data_a;
+			q_a <= data_a;
+		end
+		q_a <= ram[addr_a];
+	end
+endmodule
diff --git a/tests/xilinx/memory.ys b/tests/xilinx/memory.ys
new file mode 100644
index 000000000..5402513a2
--- /dev/null
+++ b/tests/xilinx/memory.ys
@@ -0,0 +1,17 @@
+read_verilog memory.v
+hierarchy -top top
+proc
+memory -nomap
+equiv_opt -run :prove -map +/xilinx/cells_sim.v synth_xilinx
+memory
+opt -full
+
+miter -equiv -flatten -make_assert -make_outputs gold gate miter
+sat -verify -prove-asserts -seq 5 -set-init-zero -show-inputs -show-outputs miter
+
+design -load postopt
+cd top
+select -assert-count 1 t:BUFG
+select -assert-count 8 t:FDRE
+select -assert-count 8 t:RAM64X1D
+select -assert-none t:BUFG t:FDRE t:RAM64X1D %% t:* %D
diff --git a/tests/xilinx/mul.v b/tests/xilinx/mul.v
new file mode 100644
index 000000000..d5b48b1d7
--- /dev/null
+++ b/tests/xilinx/mul.v
@@ -0,0 +1,11 @@
+module top
+(
+ input [5:0] x,
+ input [5:0] y,
+
+ output [11:0] A,
+ );
+
+assign A =  x * y;
+
+endmodule
diff --git a/tests/xilinx/mul.ys b/tests/xilinx/mul.ys
new file mode 100644
index 000000000..ec30c9c2c
--- /dev/null
+++ b/tests/xilinx/mul.ys
@@ -0,0 +1,15 @@
+read_verilog mul.v
+hierarchy -top top
+equiv_opt -assert -map +/xilinx/cells_sim.v synth_xilinx # equivalency check
+design -load postopt # load the post-opt design (otherwise equiv_opt loads the pre-opt design)
+cd top # Constrain all select calls below inside the top module
+
+select -assert-count 12 t:LUT2
+select -assert-count 1  t:LUT3
+select -assert-count 6  t:LUT4
+select -assert-count 1  t:LUT5
+select -assert-count 33 t:LUT6
+select -assert-count 11 t:MUXCY
+select -assert-count 1  t:MUXF7
+select -assert-count 12 t:XORCY
+select -assert-none t:FDRE t:LUT2 t:LUT3 t:LUT4 t:LUT5 t:LUT6 t:MUXCY t:MUXF7 t:XORCY %% t:* %D
diff --git a/tests/xilinx/mux.v b/tests/xilinx/mux.v
new file mode 100644
index 000000000..0814b733e
--- /dev/null
+++ b/tests/xilinx/mux.v
@@ -0,0 +1,100 @@
+module mux2 (S,A,B,Y);
+    input S;
+    input A,B;
+    output reg Y;
+
+    always @(*)
+		Y = (S)? B : A;
+endmodule
+
+module mux4 ( S, D, Y );
+
+input[1:0] S;
+input[3:0] D;
+output Y;
+
+reg Y;
+wire[1:0] S;
+wire[3:0] D;
+
+always @*
+begin
+    case( S )
+       0 : Y = D[0];
+       1 : Y = D[1];
+       2 : Y = D[2];
+       3 : Y = D[3];
+   endcase
+end
+
+endmodule
+
+module mux8 ( S, D, Y );
+
+input[2:0] S;
+input[7:0] D;
+output Y;
+
+reg Y;
+wire[2:0] S;
+wire[7:0] D;
+
+always @*
+begin
+   case( S )
+       0 : Y = D[0];
+       1 : Y = D[1];
+       2 : Y = D[2];
+       3 : Y = D[3];
+       4 : Y = D[4];
+       5 : Y = D[5];
+       6 : Y = D[6];
+       7 : Y = D[7];
+   endcase
+end
+
+endmodule
+
+module mux16 (D, S, Y);
+ 	input  [15:0] D;
+ 	input  [3:0] S;
+ 	output Y;
+
+assign Y = D[S];
+
+endmodule
+
+
+module top (
+input [3:0] S,
+input [15:0] D,
+output M2,M4,M8,M16
+);
+
+mux2 u_mux2 (
+        .S (S[0]),
+        .A (D[0]),
+        .B (D[1]),
+        .Y (M2)
+    );
+
+
+mux4 u_mux4 (
+        .S (S[1:0]),
+        .D (D[3:0]),
+        .Y (M4)
+    );
+
+mux8 u_mux8 (
+        .S (S[2:0]),
+        .D (D[7:0]),
+        .Y (M8)
+    );
+
+mux16 u_mux16 (
+        .S (S[3:0]),
+        .D (D[15:0]),
+        .Y (M16)
+    );
+
+endmodule
diff --git a/tests/xilinx/mux.ys b/tests/xilinx/mux.ys
new file mode 100644
index 000000000..6ecee58f5
--- /dev/null
+++ b/tests/xilinx/mux.ys
@@ -0,0 +1,10 @@
+read_verilog mux.v
+proc
+flatten
+equiv_opt -assert -map +/xilinx/cells_sim.v synth_xilinx # equivalency check
+design -load postopt # load the post-opt design (otherwise equiv_opt loads the pre-opt design)
+cd top # Constrain all select calls below inside the top module
+
+select -assert-count 2  t:LUT3
+select -assert-count 5  t:LUT6
+select -assert-none t:LUT3 t:LUT6 %% t:* %D
diff --git a/tests/xilinx/run-test.sh b/tests/xilinx/run-test.sh
index ea56b70f0..2c72ca3a9 100755
--- a/tests/xilinx/run-test.sh
+++ b/tests/xilinx/run-test.sh
@@ -6,7 +6,7 @@ for x in *.ys; do
 	echo "all:: run-$x"
 	echo "run-$x:"
 	echo "	@echo 'Running $x..'"
-	echo "	@../../yosys -ql ${x%.ys}.log $x"
+	echo "	@../../yosys -ql ${x%.ys}.log $x -w 'Yosys has only limited support for tri-state logic at the moment.'"
 done
 for s in *.sh; do
 	if [ "$s" != "run-test.sh" ]; then
diff --git a/tests/xilinx/shifter.v b/tests/xilinx/shifter.v
new file mode 100644
index 000000000..c55632552
--- /dev/null
+++ b/tests/xilinx/shifter.v
@@ -0,0 +1,22 @@
+module top    (

+out,

+clk,

+in

+);

+    output [7:0] out;

+    input signed clk, in;

+    reg signed [7:0] out = 0;

+

+    always @(posedge clk)

+	begin

+`ifndef BUG

+		out    <= out >> 1;

+		out[7] <= in;

+`else

+

+		out    <= out << 1;

+		out[7] <= in;

+`endif

+	end

+

+endmodule

diff --git a/tests/xilinx/shifter.ys b/tests/xilinx/shifter.ys
new file mode 100644
index 000000000..84e16f41e
--- /dev/null
+++ b/tests/xilinx/shifter.ys
@@ -0,0 +1,11 @@
+read_verilog shifter.v
+hierarchy -top top
+proc
+flatten
+equiv_opt -assert -map +/xilinx/cells_sim.v synth_xilinx # equivalency check
+design -load postopt # load the post-opt design (otherwise equiv_opt loads the pre-opt design)
+cd top # Constrain all select calls below inside the top module
+
+select -assert-count 1 t:BUFG
+select -assert-count 8 t:FDRE
+select -assert-none t:BUFG t:FDRE %% t:* %D
diff --git a/tests/xilinx/tribuf.v b/tests/xilinx/tribuf.v
new file mode 100644
index 000000000..3fa6eb6c6
--- /dev/null
+++ b/tests/xilinx/tribuf.v
@@ -0,0 +1,29 @@
+module tristate (en, i, o);
+    input en;
+    input i;
+    output reg o;
+`ifndef BUG 
+    
+    always @(en or i)
+		o <= (en)? i : 1'bZ;
+`else
+	
+    always @(en or i)
+		o <= (en)? ~i : 1'bZ;
+`endif
+endmodule
+
+
+module top (
+input en,
+input a,
+output b
+);
+
+tristate u_tri (
+        .en (en ),
+        .i (a ),
+        .o (b )
+    );
+
+endmodule
diff --git a/tests/xilinx/tribuf.ys b/tests/xilinx/tribuf.ys
new file mode 100644
index 000000000..fc7ed37ef
--- /dev/null
+++ b/tests/xilinx/tribuf.ys
@@ -0,0 +1,11 @@
+read_verilog tribuf.v
+hierarchy -top top
+proc
+tribuf
+flatten
+synth
+equiv_opt -assert -map +/xilinx/cells_sim.v -map +/simcells.v synth_xilinx # equivalency check
+design -load postopt # load the post-opt design (otherwise equiv_opt loads the pre-opt design)
+cd top # Constrain all select calls below inside the top module
+select -assert-count 1 t:$_TBUF_
+select -assert-none t:$_TBUF_ %% t:* %D