Fix structure parameter constant propagation, bug968.

Signed-off-by: Wilson Snyder <wsnyder@wsnyder.org>

Changes

@@ -13,6 +13,8 @@ indicates the contributor was also the author of the fix; Thanks!
 
 ****  Fix internal error on dotted refs into generates, bug958. [Jie Xu]
 
+****  Fix structure parameter constant propagation, bug968. [Todd Strader]
+
 ****  Fix mis-optimizing public DPI functions, bug963. [Wei Song]
 
 

src/V3Simulate.h

@@ -261,7 +261,8 @@ private:
 	// as we don't figure out variable ordering.
 	// Delayed is OK though, as we'll decode the next state separately.
 	if (!nodep->varp()->dtypeSkipRefp()->castBasicDType()
-            && !nodep->varp()->dtypeSkipRefp()->castPackArrayDType())
+            && !nodep->varp()->dtypeSkipRefp()->castPackArrayDType()
+            && !nodep->varp()->dtypeSkipRefp()->castStructDType())
             clearOptimizable(nodep,"Array references/not basic");
 	if (nodep->lvalue()) {
 	    if (m_inDlyAssign) {

test_regress/t/t_static_elab_struct.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 2003 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;

test_regress/t/t_static_elab_struct.v

@@ -0,0 +1,32 @@
+// DESCRIPTION: Verilator: Simple static elaboration case
+//
+// This file ONLY is placed into the Public Domain, for any use,
+// without warranty, 2015 by Todd Strader.
+
+module t (/*AUTOARG*/);
+
+   typedef struct packed {
+      logic [ 31 : 0 ] _five;
+   } five_t;
+
+   function five_t gimme_five ();
+      automatic five_t result;
+
+      result._five = 5;
+
+      return result;
+   endfunction
+
+   localparam five_t FIVE = gimme_five();
+
+   initial begin
+      if (FIVE._five != 5) begin
+         $display("%%Error: Got 0b%b instead of 5", FIVE._five);
+         $stop;
+      end
+
+      $write("*-* All Finished *-*\n");
+      $finish;
+   end
+
+endmodule