IVGCVSW-6145 ConstTensorsAsInput: Optimizer Fix - GetConstantTensorsByRef

 * Add functionality to check for ConstantTensorsAsInputs to GetConstantTensorsByRef
 * Reorder optimizations so RedirectMembersToConstantInputs occurs after
   Conversion of Constants
 * Ensure graph is in topological order after loading in OptimizedNet
 * Fixed test to check release of m_LayerOutputs.

Signed-off-by: Francis Murtagh <francis.murtagh@arm.com>
Change-Id: I7cff50798d7217e8ea0d2f9b153eabd10174a566

4 files changed, 50 insertions, 0 deletions

diff --git a/src/armnn/layers/Convolution2dLayer.cpp b/src/armnn/layers/Convolution2dLayer.cpp
index 7b3382bf93..dbbd009716 100644
--- a/src/armnn/layers/Convolution2dLayer.cpp
+++ b/src/armnn/layers/Convolution2dLayer.cpp
@@ -139,6 +139,13 @@ void Convolution2dLayer::ValidateTensorShapesFromInputs()
 
 Layer::ConstantTensors Convolution2dLayer::GetConstantTensorsByRef()
 {
+    Layer::ConstantTensors tensors = GetConnectedConstantAsInputTensors();
+
+    if (!tensors.empty())
+    {
+        return tensors;
+    }
+
     // For API stability DO NOT ALTER order and add new members to the end of vector
     return {m_Weight, m_Bias};
 }
diff --git a/src/armnn/layers/DepthwiseConvolution2dLayer.cpp b/src/armnn/layers/DepthwiseConvolution2dLayer.cpp
index 08f6fafa1b..4fd280485a 100644
--- a/src/armnn/layers/DepthwiseConvolution2dLayer.cpp
+++ b/src/armnn/layers/DepthwiseConvolution2dLayer.cpp
@@ -142,6 +142,13 @@ void DepthwiseConvolution2dLayer::ValidateTensorShapesFromInputs()
 
 Layer::ConstantTensors DepthwiseConvolution2dLayer::GetConstantTensorsByRef()
 {
+    Layer::ConstantTensors tensors = GetConnectedConstantAsInputTensors();
+
+    if (!tensors.empty())
+    {
+        return tensors;
+    }
+
     // For API stability DO NOT ALTER order and add new members to the end of vector
     return {m_Weight, m_Bias};
 }
diff --git a/src/armnn/layers/FullyConnectedLayer.cpp b/src/armnn/layers/FullyConnectedLayer.cpp
index b1ae974cd6..1f006c9d80 100644
--- a/src/armnn/layers/FullyConnectedLayer.cpp
+++ b/src/armnn/layers/FullyConnectedLayer.cpp
@@ -77,6 +77,13 @@ void FullyConnectedLayer::ValidateTensorShapesFromInputs()
 
 Layer::ConstantTensors FullyConnectedLayer::GetConstantTensorsByRef()
 {
+    Layer::ConstantTensors tensors = GetConnectedConstantAsInputTensors();
+
+    if (!tensors.empty())
+    {
+        return tensors;
+    }
+
     // For API stability DO NOT ALTER order and add new members to the end of vector
     return {m_Weight, m_Bias};
 }
diff --git a/src/armnn/layers/LayerWithParameters.hpp b/src/armnn/layers/LayerWithParameters.hpp
index 8d9ddffc24..40ade95d5c 100644
--- a/src/armnn/layers/LayerWithParameters.hpp
+++ b/src/armnn/layers/LayerWithParameters.hpp
@@ -4,6 +4,7 @@
 //
 #pragma once
 
+#include "ConstantLayer.hpp"
 #include <Layer.hpp>
 
 namespace armnn
@@ -54,6 +55,34 @@ protected:
     {
         strategy.ExecuteStrategy(this, GetParameters(), {}, GetName());
     }
+
+    Layer::ConstantTensors GetConnectedConstantAsInputTensors()
+    {
+        Layer::ConstantTensors tensors;
+        for (unsigned int i = 0; i < GetNumInputSlots(); ++i)
+        {
+            if (GetInputSlot(i).GetConnection() && GetInputSlot(i).GetConnection()->GetTensorInfo().IsConstant())
+            {
+                auto &inputLayer = GetInputSlot(i).GetConnectedOutputSlot()->GetOwningLayer();
+                if (inputLayer.GetType() == armnn::LayerType::Constant)
+                {
+                    auto &constantLayer = static_cast<ConstantLayer&>(inputLayer);
+
+                    tensors.push_back(constantLayer.m_LayerOutput);
+                }
+            }
+        }
+        if (tensors.empty())
+        {
+            const std::string warningMessage{"GetConnectedConstantAsInputTensors() called on Layer with no "
+                                             "connected Constants as Input Tensors."};
+            ARMNN_LOG(warning) << warningMessage;
+        }
+        return tensors;
+    }
 };
 
+
+
+
 } // namespace