IVGCVSW-7277 Fixed issues with FullyConnected on certain TFLite models

 * TFLite Parser:
    * Fixed issue in ParseReshape where the targetShape wasn't always calculated correctly
    * Fixed issue in ParseFullyConnected where the wrong name was used for the ReshapeLayer
    * Added an ExpandDims to the FullyConnected to ensure that we reshape the output correctly
 * TFLite Delegate:
    * Added an ExpandDims to the FullyConnected to ensure that we reshape the output correctly

Signed-off-by: Mike Kelly <mike.kelly@arm.com>
Change-Id: I129dfcb8543f8a3a297c0589c841be20ef3b6407

3 files changed, 87 insertions, 5 deletions

diff --git a/delegate/src/DelegateUtils.hpp b/delegate/src/DelegateUtils.hpp
index 850b279fea..91447576d0 100644
--- a/delegate/src/DelegateUtils.hpp
+++ b/delegate/src/DelegateUtils.hpp
@@ -1,5 +1,5 @@
 //
-// Copyright © 2022 Arm Ltd and Contributors. All rights reserved.
+// Copyright © 2020-2023 Arm Ltd and Contributors. All rights reserved.
 // SPDX-License-Identifier: MIT
 //
 
@@ -367,6 +367,52 @@ TfLiteStatus FusedActivation(TfLiteContext* tfLiteContext,
     return kTfLiteOk;
 }
 
+armnn::IConnectableLayer* AddReshapeLayer(TfLiteContext* tfLiteContext,
+                                          TfLiteNode* tfLiteNode,
+                                          armnn::IConnectableLayer* prevLayer,
+                                          armnn::TensorInfo reshapedOutputTensorInfo,
+                                          armnn::TensorInfo outputTensorInfo,
+                                          armnnDelegate::DelegateData& data)
+{
+    armnn::ReshapeDescriptor desc;
+    desc.m_TargetShape = outputTensorInfo.GetShape();
+
+    bool isSupported = false;
+    armnn::BackendId setBackend;
+    FORWARD_LAYER_SUPPORT_FUNC("RESHAPE",
+                               tfLiteContext,
+                               IsReshapeSupported,
+                               data.m_Backends,
+                               isSupported,
+                               setBackend,
+                               reshapedOutputTensorInfo,
+                               outputTensorInfo,
+                               desc);
+
+    if (!isSupported)
+    {
+        return nullptr;
+    }
+
+    armnn::IConnectableLayer* reshapeLayer = data.m_Network->AddReshapeLayer(desc);
+    reshapeLayer->SetBackendId(setBackend);
+    ARMNN_ASSERT(reshapeLayer != nullptr);
+
+    prevLayer->GetOutputSlot(0).SetTensorInfo(reshapedOutputTensorInfo);
+    reshapeLayer->GetOutputSlot(0).SetTensorInfo(outputTensorInfo);
+
+    // Connect and prepare output slots
+    for (unsigned int outputIndex = 0; outputIndex < reshapeLayer->GetNumOutputSlots(); ++outputIndex)
+    {
+        data.m_OutputSlotForNode[static_cast<unsigned long>(
+                tfLiteNode->outputs->data[outputIndex])]->Connect(reshapeLayer->GetInputSlot(0));
+        armnn::IOutputSlot& outputSlot = reshapeLayer->GetOutputSlot(outputIndex);
+        data.m_OutputSlotForNode[static_cast<unsigned long>(
+                tfLiteNode->outputs->data[outputIndex])] = &outputSlot;
+    }
+    return reshapeLayer;
+}
+
 armnn::DataType GetDataType(const TfLiteTensor& tfLiteTensor)
 {
     switch (tfLiteTensor.type)
diff --git a/delegate/src/FullyConnected.hpp b/delegate/src/FullyConnected.hpp
index a2960e299b..2243ad0e0c 100644
--- a/delegate/src/FullyConnected.hpp
+++ b/delegate/src/FullyConnected.hpp
@@ -1,11 +1,12 @@
 //
-// Copyright © 2022 Arm Ltd and Contributors. All rights reserved.
+// Copyright © 2020-2023 Arm Ltd and Contributors. All rights reserved.
 // SPDX-License-Identifier: MIT
 //
 
 #pragma once
 
 #include "DelegateUtils.hpp"
+#include "armnnUtils/TensorUtils.hpp"
 #include <armnn/utility/IgnoreUnused.hpp>
 
 #include <tensorflow/lite/builtin_ops.h>
@@ -103,6 +104,25 @@ TfLiteStatus VisitFullyConnectedOperator(DelegateData& delegateData,
 
         reshapedTensorInfo.SetShape(armnn::TensorShape{ 2, reshapedDimensions.data() });
     }
+    armnn::TensorInfo reshapedOutputTensorInfo = GetTensorInfoForTfLiteTensor(tfLiteOutputTensor);
+
+    if (outputTensorInfo.GetNumDimensions() > 2)
+    {
+        // Calculate reshape to flatten to 2D [batch_size, input_size]
+        std::vector<unsigned int> reshapedDimensions(2);
+        reshapedDimensions[1] = weightsTensorInfo.GetShape()[0];
+        reshapedDimensions[0] = outputTensorInfo.GetNumElements() / reshapedDimensions[1];
+
+        if (outputTensorInfo.GetNumElements() % reshapedDimensions[1] != 0)
+        {
+            TF_LITE_MAYBE_KERNEL_LOG(
+                    tfLiteContext,
+                    "TfLiteArmnnDelegate: Failed to deduce output tensor shape from filter size #%d #%d node #%d: ",
+                    reshapedDimensions[1], operatorCode, nodeIndex);
+            return kTfLiteError;
+        }
+        reshapedOutputTensorInfo.SetShape(armnn::TensorShape{ 2, reshapedDimensions.data() });
+    }
 
     armnn::FullyConnectedDescriptor descriptor;
     descriptor.m_TransposeWeightMatrix = true;
@@ -113,6 +133,7 @@ TfLiteStatus VisitFullyConnectedOperator(DelegateData& delegateData,
     armnn::BackendId setBackend;
     auto validateFunc = [&](const armnn::TensorInfo& outputTensorInfo, bool& isSupported)
     {
+
         FORWARD_LAYER_SUPPORT_FUNC("FULLY_CONNECTED",
                                    tfLiteContext,
                                    IsFullyConnectedSupported,
@@ -128,7 +149,7 @@ TfLiteStatus VisitFullyConnectedOperator(DelegateData& delegateData,
 
     if (!delegateData.m_Network)
     {
-        validateFunc(outputTensorInfo, isSupported);
+        validateFunc(reshapedOutputTensorInfo, isSupported);
         return isSupported ? kTfLiteOk : kTfLiteError;
     }
 
@@ -202,12 +223,27 @@ TfLiteStatus VisitFullyConnectedOperator(DelegateData& delegateData,
     }
 
     auto* tfLiteNodeParameters = reinterpret_cast<TfLiteFullyConnectedParams*>(tfLiteNode->builtin_data);
+
+    if (outputTensorInfo.GetNumDimensions() > 2)
+    {
+        layer = AddReshapeLayer(tfLiteContext, tfLiteNode, layer, reshapedOutputTensorInfo, outputTensorInfo,
+                                delegateData);
+        if (!layer)
+        {
+            TF_LITE_MAYBE_KERNEL_LOG(
+                    tfLiteContext,
+                    "TfLiteArmnnDelegate: Failed to add reshape for FullyConnected #%d node #%d: ",
+                    operatorCode,
+                    nodeIndex);
+            return kTfLiteError;
+        }
+    }
+
     if (!tfLiteNodeParameters)
     {
         // No Activation
         return kTfLiteOk;
     }
-
     // Check Activation
     TfLiteFusedActivation activationType = tfLiteNodeParameters->activation;
     return FusedActivation(tfLiteContext, tfLiteNode, activationType, layer, 0, delegateData);
diff --git a/delegate/src/test/FullyConnectedTest.cpp b/delegate/src/test/FullyConnectedTest.cpp
index c300bc72bf..3ef5cedbd7 100644
--- a/delegate/src/test/FullyConnectedTest.cpp
+++ b/delegate/src/test/FullyConnectedTest.cpp
@@ -1,5 +1,5 @@
 //
-// Copyright © 2020 Arm Ltd and Contributors. All rights reserved.
+// Copyright © 2020-2021,2023 Arm Ltd and Contributors. All rights reserved.
 // SPDX-License-Identifier: MIT
 //