-module top(input [1:0] a, output [1:0] b, output c, output d, output e);
+module abc9_test001(input a, output o);
+assign o = a;
+endmodule
+
+module abc9_test002(input [1:0] a, output o);
+assign o = a[1];
+endmodule
+
+module abc9_test003(input [1:0] a, output [1:0] o);
+assign o = a;
+endmodule
+
+module abc9_test004(input [1:0] a, output o);
+assign o = ^a;
+endmodule
+
+module abc9_test005(input [1:0] a, output o, output p);
+assign o = ^a;
+assign p = ~o;
+endmodule
+
+module abc9_test006(input [1:0] a, output [2:0] o);
+assign o[0] = ^a;
+assign o[1] = ~o[0];
+assign o[2] = o[1];
+endmodule
+
+module abc9_test007(input a, output o);
+wire b, c;
+assign c = ~a;
+assign b = c;
+abc9_test007_sub s(b, o);
+endmodule
+
+module abc9_test007_sub(input a, output b);
assign b = a;
-assign c = ^a;
-assign d = ~c;
-assign e = d;
+endmodule
+
+module abc9_test008(input a, output o);
+wire b, c;
+assign b = ~a;
+assign c = b;
+abc9_test008_sub s(b, o);
+endmodule
+
+module abc9_test008_sub(input a, output b);
+assign b = ~a;
endmodule