IVGCVSW-5410 Add front-end support for CAST

IVGCVSW-5415 Add TfLiteParser support for CAST

 * Added front end support for CAST, including support in the
Reference workload, Serialization, Deserializtion, Unit tests, and
TfLiteParser.

Signed-off-by: mathad01 <matthew.haddon@arm.com>
Change-Id: Iaf670ca5912a21ed6bc84f7f83a68b42154846bb

2 files changed, 95 insertions, 0 deletions

diff --git a/src/armnn/layers/CastLayer.cpp b/src/armnn/layers/CastLayer.cpp
new file mode 100644
index 0000000000..16dd9a3744
--- /dev/null
+++ b/src/armnn/layers/CastLayer.cpp
@@ -0,0 +1,55 @@
+//
+// Copyright © 2021 Arm Ltd and Contributors. All rights reserved.
+// SPDX-License-Identifier: MIT
+//
+#include "CastLayer.hpp"
+
+#include "LayerCloneBase.hpp"
+#include <armnn/TypesUtils.hpp>
+
+#include <backendsCommon/WorkloadData.hpp>
+#include <backendsCommon/WorkloadFactory.hpp>
+
+namespace armnn
+{
+
+CastLayer::CastLayer(const char* name)
+        : Layer(1, 1, LayerType::Cast, name)
+{
+}
+
+std::unique_ptr<IWorkload> CastLayer::CreateWorkload(const IWorkloadFactory& factory) const
+{
+    CastQueueDescriptor descriptor;
+    SetAdditionalInfo(descriptor);
+
+    return factory.CreateCast(descriptor, PrepInfoAndDesc(descriptor));
+}
+
+CastLayer* CastLayer::Clone(Graph& graph) const
+{
+    return CloneBase<CastLayer>(graph, GetName());
+}
+
+void CastLayer::ValidateTensorShapesFromInputs()
+{
+    VerifyLayerConnections(1, CHECK_LOCATION());
+
+    const TensorShape& outputShape = GetOutputSlot(0).GetTensorInfo().GetShape();
+
+    VerifyShapeInferenceType(outputShape, m_ShapeInferenceMethod);
+
+    auto inferredShapes = InferOutputShapes({ GetInputSlot(0).GetConnection()->GetTensorInfo().GetShape() });
+
+    ARMNN_ASSERT(inferredShapes.size() == 1);
+
+    ValidateAndCopyShape(outputShape, inferredShapes[0], m_ShapeInferenceMethod, "CastLayer");
+}
+
+void CastLayer::Accept(ILayerVisitor& visitor) const
+{
+    IgnoreUnused(visitor);
+    throw armnn::Exception("CastLayer VisitCastLayer is not implemented");
+}
+
+} // namespace armnn
diff --git a/src/armnn/layers/CastLayer.hpp b/src/armnn/layers/CastLayer.hpp
new file mode 100644
index 0000000000..8a9ea43934
--- /dev/null
+++ b/src/armnn/layers/CastLayer.hpp
@@ -0,0 +1,40 @@
+//
+// Copyright © 2021 Arm Ltd and Contributors. All rights reserved.
+// SPDX-License-Identifier: MIT
+//
+
+#pragma once
+
+#include "Layer.hpp"
+
+namespace armnn
+{
+
+/// This layer represents a cast operation
+class CastLayer : public Layer
+{
+public:
+    /// Makes a workload for the Cast type.
+    /// @param [in] factory The workload factory which will create the workload.
+    /// @return A pointer to the created workload, or nullptr if not created.
+    virtual std::unique_ptr <IWorkload> CreateWorkload(const IWorkloadFactory &factory) const override;
+
+    /// Creates a dynamically-allocated copy of this layer.
+    /// @param [in] graph The graph into which this layer is being cloned.
+    CastLayer* Clone(Graph& graph) const override;
+
+    /// Check if the input tensor shape(s)
+    /// will lead to a valid configuration of @ref ConvertFp16ToFp32Layer.
+    /// @param [in] shapeInferenceMethod Indicates if output shape shall be overwritten or just validated.
+    void ValidateTensorShapesFromInputs() override;
+
+    void Accept(ILayerVisitor& visitor) const override;
+
+protected:
+    /// Constructor to create a CastLayer.
+    CastLayer(const char *name);
+
+    /// Default destructor
+    ~CastLayer() = default;
+};
+} // namespace armnn
\ No newline at end of file