3 files changed, 10 insertions, 5 deletions
diff --git a/libs/subcircuit/README b/libs/subcircuit/README
index f304d2a5..757a9f54 100644
--- a/libs/subcircuit/README
+++ b/libs/subcircuit/README
@@ -266,7 +266,9 @@ After this code has been executed, the results vector contains all
 non-overlapping matches of the three macrocells. The method
 clearOverlapHistory() can be used to reset the internal state used
 for this feature. The default value for the third argument to solve()
-is true (allow overlapping).
+is true (allow overlapping). The optional boolean fourth argument to the
+Graph::createNode() method can be used to mark a node as shareable even
+in non-overlapping solver mode.
 
 The solve() method also has a fourth optional integer argument. If it is set to
 a positive integer, this integer specifies the maximum number of solutions to
diff --git a/libs/subcircuit/subcircuit.cc b/libs/subcircuit/subcircuit.cc
index 73152c3b..f05aeaa2 100644
--- a/libs/subcircuit/subcircuit.cc
+++ b/libs/subcircuit/subcircuit.cc
@@ -100,7 +100,7 @@ bool SubCircuit::Graph::BitRef::operator < (const BitRef &other) const
 	return bitIdx < other.bitIdx;
 }
 
-void  SubCircuit::Graph::createNode(std::string nodeId, std::string typeId, void *userData)
+void  SubCircuit::Graph::createNode(std::string nodeId, std::string typeId, void *userData, bool shared)
 {
 	assert(nodeMap.count(nodeId) == 0);
 	nodeMap[nodeId] = nodes.size();
@@ -110,6 +110,7 @@ void  SubCircuit::Graph::createNode(std::string nodeId, std::string typeId, void
 	newNode.nodeId = nodeId;
 	newNode.typeId = typeId;
 	newNode.userData = userData;
+	newNode.shared = shared;
 }
 
 void SubCircuit::Graph::createPort(std::string nodeId, std::string portId, int width, int minWidth)
@@ -1074,7 +1075,8 @@ class SubCircuit::SolverWorker
 			}
 
 			for (int j = 0; j < int(enumerationMatrix.size()); j++)
-				haystack.usedNodes[*enumerationMatrix[j].begin()] = true;
+				if (!haystack.graph.nodes[*enumerationMatrix[j].begin()].shared)
+					haystack.usedNodes[*enumerationMatrix[j].begin()] = true;
 
 			if (verbose) {
 				my_printf("\nSolution:\n");
diff --git a/libs/subcircuit/subcircuit.h b/libs/subcircuit/subcircuit.h
index b9399a99..80eafbc3 100644
--- a/libs/subcircuit/subcircuit.h
+++ b/libs/subcircuit/subcircuit.h
@@ -63,7 +63,8 @@ namespace SubCircuit
 			std::map<std::string, int> portMap;
 			std::vector<Port> ports;
 			void *userData;
-			Node() : userData(NULL) { };
+			bool shared;
+			Node() : userData(NULL), shared(false) { };
 		};
 
 		bool allExtern;
@@ -75,7 +76,7 @@ namespace SubCircuit
 		Graph() : allExtern(false) { };
 		Graph(const Graph &other, const std::vector<std::string> &otherNodes);
 
-		void createNode(std::string nodeId, std::string typeId, void *userData = NULL);
+		void createNode(std::string nodeId, std::string typeId, void *userData = NULL, bool shared = false);
 		void createPort(std::string nodeId, std::string portId, int width = 1, int minWidth = -1);
 		void createConnection(std::string fromNodeId, std::string fromPortId, int fromBit, std::string toNodeId, std::string toPortId, int toBit, int width = 1);
 		void createConnection(std::string fromNodeId, std::string fromPortId, std::string toNodeId, std::string toPortId);