[INFRA] Import NVIDIA/CCCL upstream as optimization reference library

CCCL (CUDA C++ Core Libraries) provides:
- CUB: device/block/warp-level GPU primitives (reduce, scan, sort, topk)
- Thrust: high-level parallel algorithms (transform_reduce, sort, scan)
- libcudacxx: CUDA C++ standard library (atomics, barriers, memory)
- cudax: experimental features (memory resources, allocators)
- Tuning policies: per-SM hardware-specific algorithm parameters

Competition optimization vectors mapped to CCCL:
- Output TPS (83% weight): warp_reduce, block_reduce, device_topk
- Input TPS (14% weight): device_scan, block_load, prefetch
- Cache TPS (3% weight): prefix caching strategy patterns
- Memory (0.9 util): pooled/cached/buddy allocators

Source: https://github.com/NVIDIA/cccl (shallow clone, HEAD only)
License: Apache-2.0

cccl_upstream/thrust/testing/transform_reduce.cu

@@ -0,0 +1,104 @@
+#include <thrust/iterator/counting_iterator.h>
+#include <thrust/iterator/iterator_traits.h>
+#include <thrust/iterator/retag.h>
+#include <thrust/transform_reduce.h>
+
+#include <unittest/unittest.h>
+
+template <typename InputIterator, typename UnaryFunction, typename OutputType, typename BinaryFunction>
+OutputType
+transform_reduce(my_system& system, InputIterator, InputIterator, UnaryFunction, OutputType init, BinaryFunction)
+{
+  system.validate_dispatch();
+  return init;
+}
+
+void TestTransformReduceDispatchExplicit()
+{
+  thrust::device_vector<int> vec(1);
+
+  my_system sys(0);
+  thrust::transform_reduce(sys, vec.begin(), vec.begin(), 0, 0, 0);
+
+  ASSERT_EQUAL(true, sys.is_valid());
+}
+DECLARE_UNITTEST(TestTransformReduceDispatchExplicit);
+
+template <typename InputIterator, typename UnaryFunction, typename OutputType, typename BinaryFunction>
+OutputType transform_reduce(my_tag, InputIterator first, InputIterator, UnaryFunction, OutputType init, BinaryFunction)
+{
+  *first = 13;
+  return init;
+}
+
+void TestTransformReduceDispatchImplicit()
+{
+  thrust::device_vector<int> vec(1);
+
+  thrust::transform_reduce(thrust::retag<my_tag>(vec.begin()), thrust::retag<my_tag>(vec.begin()), 0, 0, 0);
+
+  ASSERT_EQUAL(13, vec.front());
+}
+DECLARE_UNITTEST(TestTransformReduceDispatchImplicit);
+
+template <class Vector>
+void TestTransformReduceSimple()
+{
+  using T = typename Vector::value_type;
+
+  Vector data{1, -2, 3};
+
+  T init   = 10;
+  T result = thrust::transform_reduce(data.begin(), data.end(), ::cuda::std::negate<T>(), init, ::cuda::std::plus<T>());
+
+  ASSERT_EQUAL(result, 8);
+}
+DECLARE_VECTOR_UNITTEST(TestTransformReduceSimple);
+
+template <typename T>
+void TestTransformReduce(const size_t n)
+{
+  thrust::host_vector<T> h_data   = unittest::random_integers<T>(n);
+  thrust::device_vector<T> d_data = h_data;
+
+  T init = 13;
+
+  T cpu_result =
+    thrust::transform_reduce(h_data.begin(), h_data.end(), ::cuda::std::negate<T>(), init, ::cuda::std::plus<T>());
+  T gpu_result =
+    thrust::transform_reduce(d_data.begin(), d_data.end(), ::cuda::std::negate<T>(), init, ::cuda::std::plus<T>());
+
+  ASSERT_ALMOST_EQUAL(cpu_result, gpu_result);
+}
+DECLARE_VARIABLE_UNITTEST(TestTransformReduce);
+
+template <typename T>
+void TestTransformReduceFromConst(const size_t n)
+{
+  thrust::host_vector<T> h_data   = unittest::random_integers<T>(n);
+  thrust::device_vector<T> d_data = h_data;
+
+  T init = 13;
+
+  T cpu_result =
+    thrust::transform_reduce(h_data.cbegin(), h_data.cend(), ::cuda::std::negate<T>(), init, ::cuda::std::plus<T>());
+  T gpu_result =
+    thrust::transform_reduce(d_data.cbegin(), d_data.cend(), ::cuda::std::negate<T>(), init, ::cuda::std::plus<T>());
+
+  ASSERT_ALMOST_EQUAL(cpu_result, gpu_result);
+}
+DECLARE_VARIABLE_UNITTEST(TestTransformReduceFromConst);
+
+template <class Vector>
+void TestTransformReduceCountingIterator()
+{
+  using T     = typename Vector::value_type;
+  using space = typename thrust::iterator_system<typename Vector::iterator>::type;
+
+  thrust::counting_iterator<T, space> first(1);
+
+  T result = thrust::transform_reduce(first, first + 3, ::cuda::std::negate<short>(), 0, ::cuda::std::plus<short>());
+
+  ASSERT_EQUAL(result, -6);
+}
+DECLARE_INTEGRAL_VECTOR_UNITTEST(TestTransformReduceCountingIterator);