From 8f2bc6e028eb3bab7aafc07ef21a08f5179ffb07 Mon Sep 17 00:00:00 2001
From: Wilson Snyder <wsnyder@wsnyder.org>
Date: Wed, 22 Mar 2017 17:34:47 -0400
Subject: [PATCH] Patch to fix for bug1135.

---
 src/V3Inst.cpp                        | 20 ++++++++++++++------
 test_regress/t/t_interface_arraymux.v | 15 +++++++++++++++
 2 files changed, 29 insertions(+), 6 deletions(-)

diff --git a/src/V3Inst.cpp b/src/V3Inst.cpp
index 737090dde..ae65ed26f 100644
--- a/src/V3Inst.cpp
+++ b/src/V3Inst.cpp
@@ -333,15 +333,18 @@ private:
 	    // Clone the var referenced by the pin, and clone each var referenced by the varref
 	    // Clone pin varp:
 	    for (int i = pinArrp->lsb(); i <= pinArrp->msb(); ++i) {
-		AstIfaceRefDType* ifaceRefp = pinArrp->subDTypep()->castIfaceRefDType();
-		ifaceRefp->cellp(NULL);
-
 		string varNewName = pinVarp->name() + "__BRA__" + cvtToStr(i) + "__KET__";
 		VarNameMap::iterator it = m_modVarNameMap.find(varNewName);
-		AstVar* varNewp;
-		if (it != m_modVarNameMap.end()) {
-		    varNewp = it->second;
+		AstVar* varNewp = NULL;
+
+		// Only clone the var once for each module
+		if (!pinVarp->backp()) {
+		    if (it != m_modVarNameMap.end()) {
+			varNewp = it->second;
+		    }
 		} else {
+		    AstIfaceRefDType* ifaceRefp = pinArrp->subDTypep()->castIfaceRefDType();
+		    ifaceRefp->cellp(NULL);
 		    varNewp = pinVarp->cloneTree(false);
 		    m_modVarNameMap.insert(make_pair(varNewName, varNewp));
 		    varNewp->name(varNewName);
@@ -353,6 +356,11 @@ private:
 			prevp->addNextHere(varNewp);
 		    }
 		}
+		if (varNewp == NULL) {
+		    nodep->v3fatalSrc("Module dearray failed\n");
+		}
+
+		// But clone the pin for each module instance
 		// Now also clone the pin itself and update its varref
 		AstPin* newp = nodep->cloneTree(false);
 		newp->modVarp(varNewp);
diff --git a/test_regress/t/t_interface_arraymux.v b/test_regress/t/t_interface_arraymux.v
index a77232702..e9345a5cd 100644
--- a/test_regress/t/t_interface_arraymux.v
+++ b/test_regress/t/t_interface_arraymux.v
@@ -102,4 +102,19 @@ module t
     .uids     ( uids      ),
     .thing_inp( thing_inp ),
     .thing_out( thing_out ));
+
+   // Previously there was a problem in V3Inst if non-default parameters was used
+   localparam K = 2;
+   the_intf #(.M(K)) thing_inp2();
+   the_intf #(.M(K)) thing_out2();
+
+   Thinker #(
+    .M        ( K         ),
+    .N        ( N         ))
+   thinker2(
+    .clk      ( clk       ),
+    .reset    ( reset     ),
+    .uids     ( uids      ),
+    .thing_inp( thing_inp2 ),
+    .thing_out( thing_out2 ));
 endmodule