diff --git a/test_regress/t/t_inst_dff.pl b/test_regress/t/t_inst_dff.pl
new file mode 100755
index 000000000..30da50378
--- /dev/null
+++ b/test_regress/t/t_inst_dff.pl
@@ -0,0 +1,18 @@
+#!/usr/bin/perl
+if (!$::Driver) { use FindBin; exec("$FindBin::Bin/bootstrap.pl", @ARGV, $0); die; }
+# DESCRIPTION: Verilator: Verilog Test driver/expect definition
+#
+# Copyright 2004 by Wilson Snyder. This program is free software; you can
+# redistribute it and/or modify it under the terms of either the GNU
+# Lesser General Public License Version 3 or the Perl Artistic License
+# Version 2.0.
+
+compile (
+    );
+
+execute (
+    check_finished=>1,
+    );
+
+ok(1);
+1;
diff --git a/test_regress/t/t_inst_dff.v b/test_regress/t/t_inst_dff.v
new file mode 100644
index 000000000..053b427fe
--- /dev/null
+++ b/test_regress/t/t_inst_dff.v
@@ -0,0 +1,131 @@
+// DESCRIPTION: Verilator: Verilog Test module
+//
+// This file ONLY is placed into the Public Domain, for any use,
+// without warranty, 2012 by Wilson Snyder.
+
+module t (/*AUTOARG*/
+   // Inputs
+   clk
+   );
+   input clk;
+
+   integer 	cyc=0;
+   reg [63:0] 	crc;
+   reg [63:0] 	sum;
+
+   // Take CRC data and apply to testblock inputs
+   wire [31:0]  in = crc[31:0];
+
+   localparam WIDTH = 31;
+
+   /*AUTOWIRE*/
+   // Beginning of automatic wires (for undeclared instantiated-module outputs)
+   wire [WIDTH-1:0]	b;			// From test of Test.v
+   wire [WIDTH-1:0]	c;			// From test of Test.v
+   // End of automatics
+   reg 			rst_l;
+
+   Test #(.WIDTH(WIDTH))
+   test (/*AUTOINST*/
+	 // Outputs
+	 .b				(b[WIDTH-1:0]),
+	 .c				(c[WIDTH-1:0]),
+	 // Inputs
+	 .clk				(clk),
+	 .rst_l				(rst_l),
+	 .in				(in[WIDTH-1:0]));
+
+   // Aggregate outputs into a single result vector
+   wire [63:0] result = {1'h0, c, 1'b0, b};
+
+   // Test loop
+   always @ (posedge clk) begin
+`ifdef TEST_VERBOSE
+      $write("[%0t] cyc==%0d crc=%x result=%x\n",$time, cyc, crc, result);
+`endif
+      cyc <= cyc + 1;
+      crc <= {crc[62:0], crc[63]^crc[2]^crc[0]};
+      sum <= result ^ {sum[62:0],sum[63]^sum[2]^sum[0]};
+      if (cyc==0) begin
+	 // Setup
+	 crc <= 64'h5aef0c8d_d70a4497;
+	 sum <= 64'h0;
+	 rst_l <= ~1'b1;
+      end
+      else if (cyc<10) begin
+	 sum <= 64'h0;
+	 rst_l <= ~1'b1;
+	 // Hold reset while summing
+      end
+      else if (cyc<20) begin
+	 rst_l <= ~1'b0;
+      end
+      else if (cyc<90) begin
+      end
+      else if (cyc==99) begin
+	 $write("[%0t] cyc==%0d crc=%x sum=%x\n",$time, cyc, crc, sum);
+	 if (crc !== 64'hc77bb9b3784ea091) $stop;
+	 // What checksum will we end up with (above print should match)
+`define EXPECTED_SUM 64'hbcfcebdb75ec9d32
+	 if (sum !== `EXPECTED_SUM) $stop;
+	 $write("*-* All Finished *-*\n");
+	 $finish;
+      end
+   end
+
+endmodule
+
+module Test (/*AUTOARG*/
+   // Outputs
+   b, c,
+   // Inputs
+   clk, rst_l, in
+   );
+
+   parameter    WIDTH = 5;
+
+   input                 clk;
+   input 		 rst_l;
+
+   input [WIDTH-1:0] 	 in;
+   output wire [WIDTH-1:0] 	b;
+   output wire [WIDTH-1:0] 	c;
+
+   dff # ( .WIDTH	(WIDTH),
+	   .RESET	('0),   // Although this is a single bit, the parameter must be the specified type
+	   .RESET_WIDTH (1) )
+   sub1
+     ( .clk(clk), .rst_l(rst_l), .q(b), .d(in) );
+
+   dff # ( .WIDTH	(WIDTH),
+	   .RESET	({ 1'b1, {(WIDTH-1){1'b0}} }),
+	   .RESET_WIDTH (WIDTH))
+   sub2
+     ( .clk(clk), .rst_l(rst_l), .q(c), .d(in) );
+
+endmodule
+
+module dff (/*AUTOARG*/
+   // Outputs
+   q,
+   // Inputs
+   clk, rst_l, d
+   );
+
+   parameter WIDTH = 1;
+   parameter RESET = {WIDTH{1'b0}};
+   parameter RESET_WIDTH = WIDTH;
+
+   input   clk;
+   input   rst_l;
+   input [WIDTH-1:0] d;
+   output reg [WIDTH-1:0] q;
+
+   always_ff @(posedge clk or negedge rst_l) begin
+      if ($bits(RESET) != RESET_WIDTH) $stop;
+      // verilator lint_off WIDTH
+      if (~rst_l) q <= RESET;
+      // verilator lint_on WIDTH
+      else q <= d;
+   end
+endmodule