[SYCL] This PR adds the minimum modifications to the Eigen unsupported module required to run it on devices supporting SYCL.

* Abstracting the pointer type so that both SYCL memory and pointer can be captured.
* Converting SYCL virtual pointer to SYCL device memory in Eigen evaluator class.
* Binding SYCL placeholder accessor to command group handler by using bind method in Eigen evaluator node.
* Adding SYCL macro for controlling loop unrolling.
* Modifying the TensorDeviceSycl.h and SYCL executor method to adopt the above changes.

1 files changed, 24 insertions, 8 deletions

diff --git a/unsupported/Eigen/CXX11/src/Tensor/TensorConversion.h b/unsupported/Eigen/CXX11/src/Tensor/TensorConversion.h
index 938fd0f34..e96f31537 100644
--- a/unsupported/Eigen/CXX11/src/Tensor/TensorConversion.h
+++ b/unsupported/Eigen/CXX11/src/Tensor/TensorConversion.h
@@ -129,6 +129,7 @@ struct PacketConverter<TensorEvaluator, SrcPacket, TgtPacket, 1, 2> {
       typedef typename internal::unpacket_traits<TgtPacket>::type TgtType;
       internal::scalar_cast_op<SrcType, TgtType> converter;
       EIGEN_ALIGN_MAX typename internal::unpacket_traits<TgtPacket>::type values[TgtPacketSize];
+      EIGEN_UNROLL_LOOP
       for (int i = 0; i < TgtPacketSize; ++i) {
         values[i] = converter(m_impl.coeff(index+i));
       }
@@ -164,15 +165,15 @@ class TensorConversionOp : public TensorBase<TensorConversionOp<TargetType, XprT
     typename XprType::Nested m_xpr;
 };
 
-template <bool SameType, typename Eval, typename Scalar> struct ConversionSubExprEval {
-  static EIGEN_DEVICE_FUNC EIGEN_STRONG_INLINE bool run(Eval& impl, Scalar*) {
+template <bool SameType, typename Eval, typename EvalPointerType> struct ConversionSubExprEval {
+  static EIGEN_DEVICE_FUNC EIGEN_STRONG_INLINE bool run(Eval& impl, EvalPointerType) {
     impl.evalSubExprsIfNeeded(NULL);
     return true;
   }
 };
 
-template <typename Eval, typename Scalar> struct ConversionSubExprEval<true, Eval, Scalar> {
-  static EIGEN_DEVICE_FUNC EIGEN_STRONG_INLINE bool run(Eval& impl, Scalar* data) {
+template <typename Eval, typename EvalPointerType> struct ConversionSubExprEval<true, Eval, EvalPointerType> {
+  static EIGEN_DEVICE_FUNC EIGEN_STRONG_INLINE bool run(Eval& impl, EvalPointerType data) {
     return impl.evalSubExprsIfNeeded(data);
   }
 };
@@ -207,6 +208,7 @@ struct PacketConv {
   static EIGEN_DEVICE_FUNC EIGEN_STRONG_INLINE TargetPacket run(const TensorEvaluator<ArgType, Device>& impl, Index index) {
     internal::scalar_cast_op<SrcType, TargetType> converter;
     EIGEN_ALIGN_MAX typename internal::remove_const<TargetType>::type values[PacketSize];
+    EIGEN_UNROLL_LOOP
     for (int i = 0; i < PacketSize; ++i) {
       values[i] = converter(impl.coeff(index+i));
     }
@@ -267,10 +269,18 @@ struct TensorEvaluator<const TensorConversionOp<TargetType, ArgType>, Device>
   typedef typename PacketType<SrcType, Device>::type PacketSourceType;
   static const int PacketSize = PacketType<CoeffReturnType, Device>::size;
   static const bool IsSameType = internal::is_same<TargetType, SrcType>::value;
+  typedef StorageMemory<CoeffReturnType, Device> Storage;
+  typedef typename Storage::Type EvaluatorPointerType;
 
   enum {
     IsAligned = false,
-    PacketAccess = true,
+    PacketAccess =
+    #ifndef EIGEN_USE_SYCL
+    true,
+    #else
+    TensorEvaluator<ArgType, Device>::PacketAccess &
+        internal::type_casting_traits<SrcType, TargetType>::VectorizedCast,
+    #endif
     BlockAccess = false,
     PreferBlockAccess = false,
     Layout = TensorEvaluator<ArgType, Device>::Layout,
@@ -284,9 +294,9 @@ struct TensorEvaluator<const TensorConversionOp<TargetType, ArgType>, Device>
 
   EIGEN_DEVICE_FUNC EIGEN_STRONG_INLINE const Dimensions& dimensions() const { return m_impl.dimensions(); }
 
-  EIGEN_DEVICE_FUNC EIGEN_STRONG_INLINE bool evalSubExprsIfNeeded(Scalar* data)
+  EIGEN_DEVICE_FUNC EIGEN_STRONG_INLINE bool evalSubExprsIfNeeded(EvaluatorPointerType data)
   {
-    return ConversionSubExprEval<IsSameType, TensorEvaluator<ArgType, Device>, Scalar>::run(m_impl, data);
+    return ConversionSubExprEval<IsSameType, TensorEvaluator<ArgType, Device>, EvaluatorPointerType>::run(m_impl, data);
   }
 
   EIGEN_DEVICE_FUNC EIGEN_STRONG_INLINE void cleanup()
@@ -330,10 +340,16 @@ struct TensorEvaluator<const TensorConversionOp<TargetType, ArgType>, Device>
     }
   }
 
-  EIGEN_DEVICE_FUNC typename Eigen::internal::traits<XprType>::PointerType data() const { return NULL; }
+  EIGEN_DEVICE_FUNC EvaluatorPointerType data() const { return NULL; }
 
   /// required by sycl in order to extract the sycl accessor
   const TensorEvaluator<ArgType, Device>& impl() const { return m_impl; }
+#ifdef EIGEN_USE_SYCL
+  // binding placeholder accessors to a command group handler for SYCL
+  EIGEN_DEVICE_FUNC EIGEN_STRONG_INLINE void bind(cl::sycl::handler &cgh) const {
+    m_impl.bind(cgh);
+  }
+#endif
 
  protected:
   TensorEvaluator<ArgType, Device> m_impl;