Avoid circular include dependency in reduction.cuh

cpp/include/raft/util/reduction.cuh

@@ -19,7 +19,6 @@
 #include <raft/core/cudart_utils.hpp>
 #include <raft/core/operators.hpp>
 #include <raft/util/cuda_dev_essentials.cuh>
-#include <raft/util/pow2_utils.cuh>
 #include <raft/util/warp_primitives.cuh>
 
 #include <stdint.h>
@@ -242,10 +241,12 @@ DI i_t binaryBlockReduce(i_t val, i_t* shmem)
 template <int logicalWarpSize, int vecWidth, typename T, typename ReduceLambda>
 DI void logicalWarpReduceVector(T* acc, int lane_id, ReduceLambda reduce_op)
 {
-  static_assert(raft::is_pow2(vecWidth), "Vec width must be a power of two.");
+  static_assert(vecWidth > 0, "Vec width must be strictly positive.");
+  static_assert(!(vecWidth & (vecWidth - 1)), "Vec width must be a power of two.");
   static_assert(logicalWarpSize >= 2 && logicalWarpSize <= 32,
                 "Logical warp size must be between 2 and 32");
-  static_assert(raft::is_pow2(logicalWarpSize), "Logical warp size must be a power of two.");
+  static_assert(!(logicalWarpSize & (logicalWarpSize - 1)),
+                "Logical warp size must be a power of two.");
 
   constexpr int shflStride   = logicalWarpSize / 2;
   constexpr int nextWarpSize = logicalWarpSize / 2;