Disable vectorization on device only when compiling for sycl

Eigen/Core

@@ -35,17 +35,17 @@
   #undef EIGEN_INTERNAL_DEBUGGING
   #endif
 
-  // Do not try to vectorize on CUDA and SYCL!
-  #ifndef EIGEN_DONT_VECTORIZE
-  #define EIGEN_DONT_VECTORIZE
-  #endif
-
   #ifdef EIGEN_EXCEPTIONS
   #undef EIGEN_EXCEPTIONS
   #endif
 
   // All functions callable from CUDA code must be qualified with __device__
   #ifdef __CUDACC__
+    // Do not try to vectorize on CUDA and SYCL!
+    #ifndef EIGEN_DONT_VECTORIZE
+    #define EIGEN_DONT_VECTORIZE
+    #endif
+
     #define EIGEN_DEVICE_FUNC __host__ __device__
     // We need math_functions.hpp to ensure that that EIGEN_USING_STD_MATH macro
     // works properly on the device side

unsupported/Eigen/CXX11/src/Tensor/TensorMeta.h

@@ -83,6 +83,27 @@ struct PacketType<half, GpuDevice> {
 };
 #endif
 
+#if defined(EIGEN_USE_SYCL)
+template <typename T>
+  struct PacketType<T, SyclDevice> {
+  typedef T type;
+  static const int size = 1;
+  enum {
+    HasAdd    = 0,
+    HasSub    = 0,
+    HasMul    = 0,
+    HasNegate = 0,
+    HasAbs    = 0,
+    HasArg    = 0,
+    HasAbs2   = 0,
+    HasMin    = 0,
+    HasMax    = 0,
+    HasConj   = 0,
+    HasSetLinear = 0,
+    HasBlend  = 0
+  };
+};
+#endif
 
 
 // Tuple mimics std::pair but works on e.g. nvcc.