[SYCL] Add basic tests of reduction properties

Signed-off-by: John Pennycook <[email protected]>

Author: Pennycook

sycl/test-e2e/Reduction/reduction_deterministic.cpp

@@ -0,0 +1,43 @@
+#include <cstdio>
+#include <cstdlib>
+#include <random>
+
+#include <sycl/sycl.hpp>
+
+namespace syclex = sycl::ext::oneapi::experimental;
+
+float sum(sycl::queue q, float *input, size_t N) {
+
+  float result = 0;
+  {
+    sycl::buffer<float> buf{&result, 1};
+
+    q.submit([&](sycl::handler &h) {
+      auto reduction = sycl::reduction(
+          buf, h, sycl::plus<>(), syclex::properties(syclex::deterministic));
+      h.parallel_for(N, reduction,
+                     [=](size_t i, auto &reducer) { reducer += input[i]; });
+    });
+  }
+  return result;
+}
+
+int main(int argc, char *argv[]) {
+
+  constexpr size_t N = 1024;
+  float *array = new float[N];
+
+  std::random_device rd;
+  std::mt19937 gen(rd());
+  std::uniform_real_distribution<float> dist(0.0f, 1.0f);
+  std::generate(array, array + N, [&]() { return dist(gen); });
+
+  sycl::queue q;
+  float x = sum(q, array, N);
+  float y = sum(q, array, N);
+
+  // NB: determinism guarantees bitwise reproducible reductions for floats
+  assert(sycl::bit_cast<unsigned int>(x) == sycl::bit_cast<unsigned int>(y));
+
+  delete[] array;
+}

sycl/test-e2e/Reduction/reduction_initialize_to_identity.cpp

@@ -0,0 +1,37 @@
+#include <cstdio>
+#include <cstdlib>
+#include <numeric>
+
+#include <sycl/sycl.hpp>
+
+namespace syclex = sycl::ext::oneapi::experimental;
+
+int sum(sycl::queue q, int *input, size_t N) {
+
+  int result = 42;
+  {
+    sycl::buffer<int> buf{&result, 1};
+
+    q.submit([&](sycl::handler &h) {
+      auto reduction =
+          sycl::reduction(buf, h, sycl::plus<>(),
+                          syclex::properties(syclex::initialize_to_identity));
+      h.parallel_for(N, reduction,
+                     [=](size_t i, auto &reducer) { reducer += input[i]; });
+    });
+  }
+  return result;
+}
+
+int main(int argc, char *argv[]) {
+
+  constexpr size_t N = 32;
+  int *array = new int[N];
+  std::iota(array, array + N, 1);
+
+  sycl::queue q;
+  int x = sum(q, array, N);
+  assert(x == 528);
+
+  delete[] array;
+}