IVGCVSW-2771 Fix SubTensor error in vgg16 ExecuteNetwork NEON

 * Add check if Sub-tensors cannot be used, call ACL function
 * Add computation of SplitAxis from SplitterDescriptor
 * Add NeonSplitterWorkload functions
 * Modify IsSplitterSupported to call ACL validate function
if sub-tensor cannot be used
 * Also check if quantization parameters match when using sub-tensors
 * Add more unit tests for Splitter in TfParser and TfLiteParser

Signed-off-by: Narumol Prangnawarat <narumol.prangnawarat@arm.com>
Change-Id: I31e4c7d055117c83c65b598c4125442173242226
diff --git a/src/backends/neon/workloads/CMakeLists.txt b/src/backends/neon/workloads/CMakeLists.txt
index f1c773d..8b2ad63 100644
--- a/src/backends/neon/workloads/CMakeLists.txt
+++ b/src/backends/neon/workloads/CMakeLists.txt
@@ -58,6 +58,7 @@
     NeonSoftmaxFloatWorkload.hpp
     NeonSoftmaxUint8Workload.cpp
     NeonSoftmaxUint8Workload.hpp
+    NeonSplitterWorkload.cpp
     NeonSplitterWorkload.hpp
     NeonSubtractionWorkload.cpp
     NeonSubtractionWorkload.hpp
diff --git a/src/backends/neon/workloads/NeonSplitterWorkload.cpp b/src/backends/neon/workloads/NeonSplitterWorkload.cpp
new file mode 100644
index 0000000..bf35939
--- /dev/null
+++ b/src/backends/neon/workloads/NeonSplitterWorkload.cpp
@@ -0,0 +1,112 @@
+//
+// Copyright © 2017 Arm Ltd. All rights reserved.
+// SPDX-License-Identifier: MIT
+//
+
+#include "NeonSplitterWorkload.hpp"
+
+#include "NeonWorkloadUtils.hpp"
+
+#include <aclCommon/ArmComputeTensorUtils.hpp>
+#include <aclCommon/ArmComputeUtils.hpp>
+#include <backendsCommon/CpuTensorHandle.hpp>
+#include <neon/NeonTensorHandle.hpp>
+
+
+namespace armnn
+{
+
+using namespace armcomputetensorutils;
+
+namespace
+{
+unsigned int CalcAclAxis(unsigned int numDimensions, unsigned int splitAxis)
+{
+    return (numDimensions - splitAxis) - 1;
+}
+
+} //namespace
+
+arm_compute::Status NeonSplitterWorkloadValidate(const TensorInfo& input,
+                                                 const std::vector<std::reference_wrapper<TensorInfo>>& outputs,
+                                                 unsigned int splitAxis)
+{
+    const arm_compute::TensorInfo aclInputInfo = BuildArmComputeTensorInfo(input);
+
+    size_t numOutputs = outputs.size();
+
+    std::vector<arm_compute::TensorInfo> aclOutputs;
+    aclOutputs.reserve(numOutputs);
+
+    std::vector<arm_compute::ITensorInfo*> aclOutputPtr;
+    aclOutputPtr.reserve(numOutputs);
+
+    for (size_t i = 0u; i < outputs.size(); ++i)
+    {
+        aclOutputs.emplace_back(BuildArmComputeTensorInfo(outputs[i]));
+        aclOutputPtr.emplace_back(&aclOutputs.back());
+    }
+
+    unsigned int aclAxis = CalcAclAxis(input.GetNumDimensions(), splitAxis);
+    return arm_compute::NESplit::validate(&aclInputInfo, aclOutputPtr, aclAxis);
+}
+
+NeonSplitterWorkload::NeonSplitterWorkload(const SplitterQueueDescriptor& descriptor, const WorkloadInfo& info)
+    : BaseWorkload<SplitterQueueDescriptor>(descriptor, info)
+{
+    bool allOutputsAreSubtensors = true;
+
+    // Check that all outputs are sub-tensors
+    for (auto output : m_Data.m_Outputs)
+    {
+        if (output && !output->GetParent())
+        {
+            // Non sub-tensor input found so we need to execute the split function
+            allOutputsAreSubtensors = false;
+            break;
+        }
+    }
+
+    if (allOutputsAreSubtensors)
+    {
+        // Can skip configuring the split function since it's not executed
+        return;
+    }
+
+    arm_compute::ITensor& input = boost::polymorphic_downcast<INeonTensorHandle*>(m_Data.m_Inputs[0])->GetTensor();
+
+    std::vector<arm_compute::ITensor *> aclOutputs;
+    for (auto output : m_Data.m_Outputs)
+    {
+        arm_compute::ITensor& aclOutput  = boost::polymorphic_pointer_downcast<INeonTensorHandle>(output)->GetTensor();
+        aclOutputs.emplace_back(&aclOutput);
+    }
+
+    // Create the layer function
+    m_Layer.reset(new arm_compute::NESplit());
+
+    // Configure input and output tensors
+    std::set<unsigned int> splitAxis = ComputeSplitAxis(descriptor.m_Parameters, m_Data.m_Inputs[0]->GetShape());
+    if (splitAxis.size() != 1)
+    {
+        throw InvalidArgumentException("Cannot derive split axis from SplitterDescriptor");
+    }
+
+    unsigned int aclAxis = CalcAclAxis(descriptor.m_Parameters.GetNumDimensions(), *splitAxis.begin());
+    m_Layer->configure(&input, aclOutputs, aclAxis);
+
+    // Prepare
+    m_Layer->prepare();
+}
+
+void NeonSplitterWorkload::Execute() const
+{
+    if (m_Layer)
+    {
+        ARMNN_SCOPED_PROFILING_EVENT_NEON("NeonSplitterWorkload_Execute");
+        m_Layer->run();
+    }
+}
+
+} //namespace armnn
+
diff --git a/src/backends/neon/workloads/NeonSplitterWorkload.hpp b/src/backends/neon/workloads/NeonSplitterWorkload.hpp
index 2a7ee19..f902566 100644
--- a/src/backends/neon/workloads/NeonSplitterWorkload.hpp
+++ b/src/backends/neon/workloads/NeonSplitterWorkload.hpp
@@ -7,18 +7,26 @@
 
 #include <backendsCommon/Workload.hpp>
 
+#include <arm_compute/runtime/NEON/NEFunctions.h>
+
+#include <functional>
+
 namespace armnn
 {
 
+arm_compute::Status NeonSplitterWorkloadValidate(const TensorInfo& input,
+                                                 const std::vector<std::reference_wrapper<TensorInfo>>& outputs,
+                                                 unsigned int splitAxis);
+
 class NeonSplitterWorkload : public BaseWorkload<SplitterQueueDescriptor>
 {
 public:
-    using BaseWorkload<SplitterQueueDescriptor>::BaseWorkload;
+    NeonSplitterWorkload(const SplitterQueueDescriptor& descriptor, const WorkloadInfo& info);
 
-    virtual void Execute() const override
-    {
-        // With subtensors, splitter is a no-op.
-    }
+    void Execute() const override;
+
+private:
+    mutable std::unique_ptr<arm_compute::NESplit> m_Layer;
 };
 
 } //namespace armnn