Clean up AliasTemporaries (#1815)

* Allow const size arrays in AliasTemporaries
* Fix integer types used

cub/cub/util_temporary_storage.cuh

@@ -51,8 +51,7 @@ CUB_NAMESPACE_BEGIN
 #ifndef DOXYGEN_SHOULD_SKIP_THIS // Do not document
 
 /**
- * @brief Alias temporaries to externally-allocated device storage (or simply return the amount of
- *        storage needed).
+ * @brief Alias temporaries to externally-allocated device storage (or simply return the amount of storage needed).
  *
  * @param[in] d_temp_storage
  *   Device-accessible allocation of temporary storage.
@@ -73,18 +72,18 @@ _CCCL_HOST_DEVICE _CCCL_FORCEINLINE cudaError_t AliasTemporaries(
   void* d_temp_storage,
   size_t& temp_storage_bytes,
   void* (&allocations)[ALLOCATIONS],
-  size_t (&allocation_sizes)[ALLOCATIONS])
+  const size_t (&allocation_sizes)[ALLOCATIONS])
 {
-  constexpr int ALIGN_BYTES = 256;
-  constexpr int ALIGN_MASK  = ~(ALIGN_BYTES - 1);
+  constexpr size_t ALIGN_BYTES = 256;
+  constexpr size_t ALIGN_MASK  = ~(ALIGN_BYTES - 1);
 
   // Compute exclusive prefix sum over allocation requests
   size_t allocation_offsets[ALLOCATIONS];
   size_t bytes_needed = 0;
   for (int i = 0; i < ALLOCATIONS; ++i)
   {
-    size_t allocation_bytes = (allocation_sizes[i] + ALIGN_BYTES - 1) & ALIGN_MASK;
-    allocation_offsets[i]   = bytes_needed;
+    const size_t allocation_bytes = (allocation_sizes[i] + ALIGN_BYTES - 1) & ALIGN_MASK;
+    allocation_offsets[i]         = bytes_needed;
     bytes_needed += allocation_bytes;
   }
   bytes_needed += ALIGN_BYTES - 1;
@@ -103,7 +102,8 @@ _CCCL_HOST_DEVICE _CCCL_FORCEINLINE cudaError_t AliasTemporaries(
   }
 
   // Alias
-  d_temp_storage = (void*) ((size_t(d_temp_storage) + ALIGN_BYTES - 1) & ALIGN_MASK);
+  d_temp_storage =
+    reinterpret_cast<void*>((reinterpret_cast<uintptr_t>(d_temp_storage) + ALIGN_BYTES - 1) & ALIGN_MASK);
   for (int i = 0; i < ALLOCATIONS; ++i)
   {
     allocations[i] = static_cast<char*>(d_temp_storage) + allocation_offsets[i];