[SYCL] Improve cl::sycl::detail::array default constructors code

Signed-off-by: Mikhail Lychkov <mikhail.lychkov@intel.com>

Author: mlychkov

sycl/include/CL/sycl/detail/array.hpp

@@ -22,46 +22,31 @@ template <int dimensions = 1> class array {
   static_assert(dimensions >= 1, "Array cannot be 0-dimensional.");
 
 public:
-  /* TODO: use common_array initialization via initialization list in
-   * constructor when memset conversion between SPIR-V and LLVM IR formats
-   * will be fixed in SPIR-V translator. */
-  template <int N = dimensions, detail::enable_if_t<(N == 1), size_t> = 0>
-  array() {
-    common_array[0] = 0;
-  }
-
-  template <int N = dimensions, detail::enable_if_t<(N == 2), size_t> = 0>
-  array() {
-    common_array[0] = 0;
-    common_array[1] = 0;
-  }
-
-  template <int N = dimensions, detail::enable_if_t<(N == 3), size_t> = 0>
-  array() {
-    common_array[0] = 0;
-    common_array[1] = 0;
-    common_array[2] = 0;
-  }
-
   /* The following constructor is only available in the array struct
    * specialization where: dimensions==1 */
   template <int N = dimensions>
-  array(typename std::enable_if<(N == 1), size_t>::type dim0)
+  array(typename std::enable_if<(N == 1), size_t>::type dim0 = 0)
       : common_array{dim0} {}
 
-  /* The following constructor is only available in the array struct
+  /* The following constructors are only available in the array struct
    * specialization where: dimensions==2 */
   template <int N = dimensions>
   array(typename std::enable_if<(N == 2), size_t>::type dim0, size_t dim1)
       : common_array{dim0, dim1} {}
 
-  /* The following constructor is only available in the array struct
+  template <int N = dimensions, detail::enable_if_t<(N == 2), size_t> = 0>
+  array() : array(0, 0) {}
+
+  /* The following constructors are only available in the array struct
    * specialization where: dimensions==3 */
   template <int N = dimensions>
   array(typename std::enable_if<(N == 3), size_t>::type dim0, size_t dim1,
         size_t dim2)
       : common_array{dim0, dim1, dim2} {}
 
+  template <int N = dimensions, detail::enable_if_t<(N == 3), size_t> = 0>
+  array() : array(0, 0, 0) {}
+
   // Conversion operators to derived classes
   operator cl::sycl::id<dimensions>() const {
     cl::sycl::id<dimensions> result;