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diff --git a/tests/simple/rotate.v b/tests/simple/rotate.v
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+
+// test case taken from amber23 verilog code
+module a23_barrel_shift_fpga_rotate(i_in, direction, shift_amount, rot_prod);
+
+input  [31:0] i_in;
+input         direction;
+input  [4:0]  shift_amount;
+output [31:0] rot_prod;
+
+// Generic rotate. Theoretical cost: 32x5 4-to-1 LUTs.
+// Practically a bit higher due to high fanout of "direction".
+generate
+genvar i, j;
+        for (i = 0; i < 5; i = i + 1)
+        begin : netgen
+                wire [31:0] in;
+                reg [31:0] out;
+                for (j = 0; j < 32; j = j + 1)
+                begin : net
+                        always @*
+                                out[j] = in[j] & (~shift_amount[i] ^ direction) |
+                                         in[wrap(j, i)] & (shift_amount[i] ^ direction);
+                end
+        end
+
+        // Order is reverted with respect to volatile shift_amount[0]
+        assign netgen[4].in = i_in;
+        for (i = 1; i < 5; i = i + 1)
+        begin : router
+                assign netgen[i-1].in = netgen[i].out;
+        end
+endgenerate
+
+// Aliasing
+assign rot_prod = netgen[0].out;
+
+function [4:0] wrap;
+input integer pos;
+input integer level;
+integer out;
+begin
+        out = pos - (1 << level);
+        wrap = out[4:0];
+end
+endfunction
+
+endmodule
+