From 3c336e179f371fa6922e90dcaaf4fc4d6f136841 Mon Sep 17 00:00:00 2001
From: Todd Strader <todd.strader@twosigma.com>
Date: Tue, 29 Sep 2015 21:02:33 -0400
Subject: [PATCH] Fix structure parameter constant propagation, bug968.

Signed-off-by: Wilson Snyder <wsnyder@wsnyder.org>
---
 Changes                                |  2 ++
 src/V3Simulate.h                       |  3 ++-
 test_regress/t/t_static_elab_struct.pl | 18 +++++++++++++++
 test_regress/t/t_static_elab_struct.v  | 32 ++++++++++++++++++++++++++
 4 files changed, 54 insertions(+), 1 deletion(-)
 create mode 100755 test_regress/t/t_static_elab_struct.pl
 create mode 100644 test_regress/t/t_static_elab_struct.v

diff --git a/Changes b/Changes
index 6463c4a07..f0a936cb4 100644
--- a/Changes
+++ b/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]
 
 
diff --git a/src/V3Simulate.h b/src/V3Simulate.h
index 2114c8ff3..b09abc03d 100644
--- a/src/V3Simulate.h
+++ b/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) {
diff --git a/test_regress/t/t_static_elab_struct.pl b/test_regress/t/t_static_elab_struct.pl
new file mode 100755
index 000000000..f91289753
--- /dev/null
+++ b/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;
diff --git a/test_regress/t/t_static_elab_struct.v b/test_regress/t/t_static_elab_struct.v
new file mode 100644
index 000000000..18a50326e
--- /dev/null
+++ b/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