Refactor SM90 radix_sort tuning (#3125)

Author: bernhardmgruber

cub/cub/device/dispatch/tuning/tuning_radix_sort.cuh

@@ -761,20 +761,19 @@ struct policy_hub
   /// SM90
   struct Policy900 : ChainedPolicy<900, Policy900, Policy800>
   {
-    enum
-    {
-      PRIMARY_RADIX_BITS     = (sizeof(KeyT) > 1) ? 7 : 5,
-      SINGLE_TILE_RADIX_BITS = (sizeof(KeyT) > 1) ? 6 : 5,
-      SEGMENTED_RADIX_BITS   = (sizeof(KeyT) > 1) ? 6 : 5,
-      ONESWEEP               = true,
-      ONESWEEP_RADIX_BITS    = 8,
-      OFFSET_64BIT           = sizeof(OffsetT) == 8 ? 1 : 0,
-      FLOAT_KEYS             = std::is_same<KeyT, float>::value ? 1 : 0,
-    };
+    static constexpr bool ONESWEEP           = true;
+    static constexpr int ONESWEEP_RADIX_BITS = 8;
 
     using HistogramPolicy    = AgentRadixSortHistogramPolicy<128, 16, 1, KeyT, ONESWEEP_RADIX_BITS>;
     using ExclusiveSumPolicy = AgentRadixSortExclusiveSumPolicy<256, ONESWEEP_RADIX_BITS>;
 
+  private:
+    static constexpr int PRIMARY_RADIX_BITS     = (sizeof(KeyT) > 1) ? 7 : 5;
+    static constexpr int SINGLE_TILE_RADIX_BITS = (sizeof(KeyT) > 1) ? 6 : 5;
+    static constexpr int SEGMENTED_RADIX_BITS   = (sizeof(KeyT) > 1) ? 6 : 5;
+    static constexpr int OFFSET_64BIT           = sizeof(OffsetT) == 8 ? 1 : 0;
+    static constexpr int FLOAT_KEYS             = ::cuda::std::is_same<KeyT, float>::value ? 1 : 0;
+
     using OnesweepPolicyKey32 = AgentRadixSortOnesweepPolicy<
       384,
       KEYS_ONLY ? 20 - OFFSET_64BIT - FLOAT_KEYS
@@ -796,11 +795,11 @@ struct policy_hub
       RADIX_SORT_STORE_DIRECT,
       ONESWEEP_RADIX_BITS>;
 
-    using OnesweepLargeKeyPolicy = //
-      ::cuda::std::_If<sizeof(KeyT) == 4, OnesweepPolicyKey32, OnesweepPolicyKey64>;
+    using OnesweepLargeKeyPolicy = ::cuda::std::_If<sizeof(KeyT) == 4, OnesweepPolicyKey32, OnesweepPolicyKey64>;
+
+    using OnesweepSmallKeyPolicySizes =
+      sm90_small_key_tuning<sizeof(KeyT), KEYS_ONLY ? 0 : sizeof(ValueT), sizeof(OffsetT)>;
 
-    using OnesweepSmallKeyPolicySizes = //
-      detail::radix::sm90_small_key_tuning<sizeof(KeyT), KEYS_ONLY ? 0 : sizeof(ValueT), sizeof(OffsetT)>;
     using OnesweepSmallKeyPolicy = AgentRadixSortOnesweepPolicy<
       OnesweepSmallKeyPolicySizes::threads,
       OnesweepSmallKeyPolicySizes::items,
@@ -810,42 +809,9 @@ struct policy_hub
       BLOCK_SCAN_RAKING_MEMOIZE,
       RADIX_SORT_STORE_DIRECT,
       8>;
-    using OnesweepPolicy = //
-      ::cuda::std::_If<sizeof(KeyT) < 4, //
-                       OnesweepSmallKeyPolicy, //
-                       OnesweepLargeKeyPolicy>;
-
-    using ScanPolicy =
-      AgentScanPolicy<512,
-                      23,
-                      OffsetT,
-                      BLOCK_LOAD_WARP_TRANSPOSE,
-                      LOAD_DEFAULT,
-                      BLOCK_STORE_WARP_TRANSPOSE,
-                      BLOCK_SCAN_RAKING_MEMOIZE>;
-
-    using DownsweepPolicy = AgentRadixSortDownsweepPolicy<
-      512,
-      23,
-      DominantT,
-      BLOCK_LOAD_TRANSPOSE,
-      LOAD_DEFAULT,
-      RADIX_RANK_MATCH,
-      BLOCK_SCAN_WARP_SCANS,
-      PRIMARY_RADIX_BITS>;
-
-    using AltDownsweepPolicy = AgentRadixSortDownsweepPolicy<
-      (sizeof(KeyT) > 1) ? 256 : 128,
-      47,
-      DominantT,
-      BLOCK_LOAD_TRANSPOSE,
-      LOAD_DEFAULT,
-      RADIX_RANK_MEMOIZE,
-      BLOCK_SCAN_WARP_SCANS,
-      PRIMARY_RADIX_BITS - 1>;
 
-    using UpsweepPolicy    = AgentRadixSortUpsweepPolicy<256, 23, DominantT, LOAD_DEFAULT, PRIMARY_RADIX_BITS>;
-    using AltUpsweepPolicy = AgentRadixSortUpsweepPolicy<256, 47, DominantT, LOAD_DEFAULT, PRIMARY_RADIX_BITS - 1>;
+  public:
+    using OnesweepPolicy = ::cuda::std::_If<sizeof(KeyT) < 4, OnesweepSmallKeyPolicy, OnesweepLargeKeyPolicy>;
 
     using SingleTilePolicy = AgentRadixSortDownsweepPolicy<
       256,