[llvm] [libsycl] Implement nd_range kernel submissions (PR #206505)

[Sergey Semenov via llvm-commits]

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@@ -0,0 +1,147 @@
+//===----------------------------------------------------------------------===//
+//
+// Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions.
+// See https://llvm.org/LICENSE.txt for license information.
+// SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception
+//
+//===----------------------------------------------------------------------===//
+///
+/// \file
+/// This file contains the declaration of the SYCL 2020 group class.
+///
+//===----------------------------------------------------------------------===//
+
+#ifndef _LIBSYCL___IMPL_GROUP_HPP
+#define _LIBSYCL___IMPL_GROUP_HPP
+
+#include <sycl/__impl/detail/config.hpp>
+#include <sycl/__impl/detail/linearization.hpp>
+#include <sycl/__impl/index_space_classes.hpp>
+#include <sycl/__impl/memory_enums.hpp>
+#include <sycl/__spirv/spirv_vars.hpp>
+
+#include <cstddef>
+
+_LIBSYCL_BEGIN_NAMESPACE_SYCL
+
+template <int> class nd_item;
+
+// SYCL2020 4.9.1.7. group class.
+/// The group class encapsulates all functionality required to represent a
+///  particular work-group within a parallel execution.
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sergey-semenov wrote:

```suggestion
/// particular work-group within a parallel execution.
```
Nit

https://github.com/llvm/llvm-project/pull/206505