diff --git a/SYCL/Reduction/reduction_internal.cpp b/SYCL/Reduction/reduction_internal.cpp
new file mode 100644
index 0000000000..d87a6e8b62
--- /dev/null
+++ b/SYCL/Reduction/reduction_internal.cpp
@@ -0,0 +1,147 @@
+// RUN: %clangxx -fsycl -fsycl-targets=%sycl_triple %s -o %t.out
+// RUN: %CPU_RUN_PLACEHOLDER %t.out
+// RUN: %GPU_RUN_PLACEHOLDER %t.out
+// RUN: %ACC_RUN_PLACEHOLDER %t.out
+
+#include <sycl/sycl.hpp>
+using namespace sycl;
+
+template <int Dims> auto get_global_range(range<Dims> Range) { return Range; }
+template <int Dims> auto get_global_range(nd_range<Dims> NDRange) {
+  return NDRange.get_global_range();
+}
+
+template <int Dims, bool WithOffset>
+auto get_global_id(item<Dims, WithOffset> Item) {
+  return Item.get_id();
+}
+template <int Dims> auto get_global_id(nd_item<Dims> NDItem) {
+  return NDItem.get_global_id();
+}
+
+template <int Dims> auto get_global_id(id<Dims> Id) { return Id; }
+
+// We can select strategy explicitly so no need to test all combinations of
+// types/operations.
+using T = int;
+using BinOpTy = std::plus<T>;
+
+// On Windows, allocating new memory and then initializing it is slow for some
+// reason (not related to reductions). Try to re-use the same memory between
+// test cases.
+struct RedStorage {
+  RedStorage(queue &q) : q(q), Ptr(malloc_device<T>(1, q)), Buf(1) {}
+  ~RedStorage() { free(Ptr, q); }
+
+  template <bool UseUSM> auto get() {
+    if constexpr (UseUSM)
+      return Ptr;
+    else
+      return Buf;
+  }
+  queue &q;
+  T *Ptr;
+  buffer<T, 1> Buf;
+};
+
+template <bool UseUSM, bool InitToIdentity,
+          detail::reduction::strategy Strategy, typename RangeTy>
+static void test(RedStorage &Storage, RangeTy Range) {
+  queue &q = Storage.q;
+
+  T Init{19};
+
+  auto Red = Storage.get<UseUSM>();
+  auto GetRedAcc = [&](handler &cgh) {
+    if constexpr (UseUSM)
+      return Red;
+    else
+      return accessor{Red, cgh};
+  };
+
+  q.submit([&](handler &cgh) {
+     auto RedAcc = GetRedAcc(cgh);
+     cgh.single_task([=]() { RedAcc[0] = Init; });
+   }).wait();
+
+  q.submit([&](handler &cgh) {
+     auto RedSycl = [&]() {
+       if constexpr (UseUSM)
+         if constexpr (InitToIdentity)
+           return reduction(Red, BinOpTy{},
+                            property::reduction::initialize_to_identity{});
+         else
+           return reduction(Red, BinOpTy{});
+       else if constexpr (InitToIdentity)
+         return reduction(Red, cgh, BinOpTy{},
+                          property::reduction::initialize_to_identity{});
+       else
+         return reduction(Red, cgh, BinOpTy{});
+     }();
+     detail::reduction_parallel_for<detail::auto_name, Strategy>(
+         cgh, Range, ext::oneapi::experimental::detail::empty_properties_t{},
+         RedSycl, [=](auto Item, auto &Red) { Red.combine(T{1}); });
+   }).wait();
+
+  auto *Result = malloc_shared<T>(1, q);
+  q.submit([&](handler &cgh) {
+     auto RedAcc = GetRedAcc(cgh);
+     cgh.single_task([=]() { *Result = RedAcc[0]; });
+   }).wait();
+
+  auto N = get_global_range(Range).size();
+  int Expected = InitToIdentity ? N : Init + N;
+#if defined(__PRETTY_FUNCTION__)
+  std::cout << __PRETTY_FUNCTION__;
+#elif defined(__FUNCSIG__)
+  std::cout << __FUNCSIG__;
+#endif
+  std::cout << ": " << *Result << ", expected " << Expected << std::endl;
+  assert(*Result == Expected);
+
+  free(Result, q);
+}
+
+template <int... Inds, class F>
+void loop_impl(std::integer_sequence<int, Inds...>, F &&f) {
+  (f(std::integral_constant<int, Inds>{}), ...);
+}
+
+template <int count, class F> void loop(F &&f) {
+  loop_impl(std::make_integer_sequence<int, count>{}, std::forward<F>(f));
+}
+
+template <bool UseUSM, bool InitToIdentity, typename RangeTy>
+void testAllStrategies(RedStorage &Storage, RangeTy Range) {
+  loop<(int)detail::reduction::strategy::multi>([&](auto Id) {
+    constexpr auto Strategy =
+        // Skip auto_select == 0.
+        detail::reduction::strategy{decltype(Id)::value + 1};
+    test<UseUSM, InitToIdentity, Strategy>(Storage, Range);
+  });
+}
+
+int main() {
+  queue q;
+  RedStorage Storage(q);
+
+  auto TestRange = [&](auto Range) {
+    testAllStrategies<true, true>(Storage, Range);
+    testAllStrategies<true, false>(Storage, Range);
+    testAllStrategies<false, true>(Storage, Range);
+    testAllStrategies<false, false>(Storage, Range);
+  };
+
+  TestRange(range<1>{42});
+  TestRange(range<2>{8, 8});
+  TestRange(range<3>{7, 7, 5});
+  TestRange(nd_range<1>{range<1>{7}, range<1>{7}});
+  TestRange(nd_range<1>{range<1>{3 * 3}, range<1>{3}});
+
+  // TODO: Strategies historically adopted from sycl::range implementation only
+  // support 1-Dim case.
+  //
+  // TestRange(nd_range<2>{range<2>{7, 3}, range<2> {7, 3}});
+  // TestRange(nd_range<2>{range<2>{14, 9}, range<2> {7, 3}});
+  return 0;
+}