IVGCVSW-7418: Can't call SubstituteSubgraph on working copy of subgraph in Optimize

 * Add unit test for WorkingCopy of SubgraphView with Inputs and Outputs
 * Added check to ensure InputSlot is connected before trying to disconnect

Signed-off-by: Matthew Bentham <matthew.bentham@arm.com>
Change-Id: I261d55e38c94687a9de64cdee726a7c7442ed537

2 files changed, 41 insertions, 6 deletions

diff --git a/src/armnn/Graph.cpp b/src/armnn/Graph.cpp
index b5769f75f3..e5d123830c 100644
--- a/src/armnn/Graph.cpp
+++ b/src/armnn/Graph.cpp
@@ -497,13 +497,19 @@ void Graph::ReplaceSubgraphConnections(const SubgraphView& subgraph, const Subgr
         IInputSlot* subgraphInputSlot = subgraphInputSlots.at(inputSlotIdx);
         ARMNN_ASSERT(subgraphInputSlot);
 
-        IOutputSlot* connectedOutputSlot = subgraphInputSlot->GetConnection();
-        ARMNN_ASSERT(connectedOutputSlot);
-        connectedOutputSlot->Disconnect(*subgraphInputSlot);
+        // Only disconnect if the InputSlot has a connection, this might not be the case when
+        // dealing with working copies of SubgraphViews
+        // Note: we don't need this check for OutputSlot as it iterates over a vector of valid connections
+        if (subgraphInputSlot->GetConnection())
+        {
+            IOutputSlot* connectedOutputSlot = subgraphInputSlot->GetConnection();
+            ARMNN_ASSERT(connectedOutputSlot);
+            connectedOutputSlot->Disconnect(*subgraphInputSlot);
 
-        IInputSlot* substituteInputSlot = substituteSubgraphInputSlots.at(inputSlotIdx);
-        ARMNN_ASSERT(substituteInputSlot);
-        connectedOutputSlot->Connect(*substituteInputSlot);
+            IInputSlot* substituteInputSlot = substituteSubgraphInputSlots.at(inputSlotIdx);
+            ARMNN_ASSERT(substituteInputSlot);
+            connectedOutputSlot->Connect(*substituteInputSlot);
+        }
     }
 
     // Step 2: process output slots
diff --git a/src/armnn/test/SubgraphViewTests.cpp b/src/armnn/test/SubgraphViewTests.cpp
index 4ce67b0fec..9bb5e69bbb 100644
--- a/src/armnn/test/SubgraphViewTests.cpp
+++ b/src/armnn/test/SubgraphViewTests.cpp
@@ -2063,6 +2063,35 @@ TEST_CASE("SubgraphViewWorkingCopySubstituteSubgraph")
     CHECK_THROWS_AS(workingCopy.GetWorkingCopy(), Exception);
 }
 
+TEST_CASE("SubgraphViewPartialWorkingCopySubstituteSubgraph")
+{
+    Graph graph;
+
+    auto input = graph.AddLayer<InputLayer>(0, "Input");
+    auto activation = graph.AddLayer<ActivationLayer>(ActivationDescriptor{}, "Activation");
+    auto output = graph.AddLayer<OutputLayer>(1, "Output");
+
+    input->GetOutputSlot(0).Connect(activation->GetInputSlot(0));
+    activation->GetOutputSlot(0).Connect(output->GetInputSlot(0));
+
+    //Add in out of order
+    auto view = CreateSubgraphViewFrom({activation},
+                                       {&activation->GetInputSlot(0)},
+                                       {&activation->GetOutputSlot(0)});
+
+    auto workingCopy = view->GetWorkingCopy();
+
+    // First (and only) layer in the subgraph is the Activation
+    CHECK(std::string((*workingCopy.beginIConnectable())->GetName()) == "Activation");
+
+    // Substitute the "Activation" layer for an equivalent layer
+    auto activation2 = graph.AddLayer<ActivationLayer>(ActivationDescriptor{}, "Activation2");
+    SubgraphView pattern(*workingCopy.beginIConnectable());
+    workingCopy.SubstituteSubgraph(pattern, activation2);
+
+    CHECK(std::string((*workingCopy.beginIConnectable())->GetName()) == "Activation2");
+}
+
 TEST_CASE("SubgraphViewWorkingCopyOptimizationViews")
 {
     Graph graph;