add predicate to ensure we don't read of the end of the scales

Co-authored-by: Tyler Michael Smith <tyler@neuralmagic.com>

csrc/quantization/cutlass_w8a8/broadcast_load_epilogue_c3x.hpp

@@ -328,28 +328,44 @@ struct Sm90ColOrScalarBroadcast {
     return EmptyProducerLoadCallbacks{};
   }
 
-  template<class GTensor, class RTensor>
+  template<class GTensor, class RTensor, class CTensor, class ProblemShape>
   struct ConsumerStoreCallbacks : EmptyConsumerStoreCallbacks {
     CUTLASS_DEVICE
-    ConsumerStoreCallbacks(GTensor&& tCgCol, RTensor&& tCrCol, Params const& params)
-      : tCgCol(cute::forward<GTensor>(tCgCol)),
-        tCrCol(cute::forward<RTensor>(tCrCol)),
-        params(params) {}
+    ConsumerStoreCallbacks(
+      GTensor&& tCgCol,
+      RTensor&& tCrCol,
+      CTensor&& tCcCol,
+      ProblemShape problem_shape,
+      Params const& params
+    ): 
+      tCgCol(cute::forward<GTensor>(tCgCol)),
+      tCrCol(cute::forward<RTensor>(tCrCol)),
+      tCcCol(cute::forward<CTensor>(tCcCol)),
+      m(get<0>(problem_shape)),
+      params(params) {}
 
     GTensor tCgCol;                                                                    // (CPY,CPY_M,CPY_N,EPI_M,EPI_N)
-    RTensor tCrCol;                                                                    // (CPY,CPY_M,CPY_N,EPI_M,EPI_N)
+    RTensor tCrCol;
+    CTensor tCcCol;                                                                    // (CPY,CPY_M,CPY_N,EPI_M,EPI_N)
     Params const& params;
+    int m;
 
     CUTLASS_DEVICE void
     begin() {
+      Tensor pred = make_tensor<bool>(shape(tCgCol));
+      CUTLASS_PRAGMA_UNROLL
+      for (int i = 0; i < size(pred); ++i) {
+        pred(i) = get<0>(tCcCol(i)) < m;
+      }
+
       if (!params.col_broadcast) {
         fill(tCrCol, *(params.ptr_col));
         return;
       }
 
       // Filter so we don't issue redundant copies over stride-0 modes
       // (only works if 0-strides are in same location, which is by construction)
-      copy_aligned(filter(tCgCol), filter(tCrCol));
+      copy_if(pred, filter(tCgCol), filter(tCrCol));
     }
 
     template <typename ElementAccumulator, int FragmentSize>
@@ -381,8 +397,20 @@ struct Sm90ColOrScalarBroadcast {
       mCol, args.tile_shape_mnk, args.tile_coord_mnkl, args.epi_tile, args.tiled_copy, args.thread_idx);
     Tensor tCrCol = make_tensor_like(tCgCol);                                          // (CPY,CPY_M,CPY_N,EPI_M,EPI_N)
 
-    return ConsumerStoreCallbacks<decltype(tCgCol), decltype(tCrCol)>(
-      cute::move(tCgCol), cute::move(tCrCol), params);
+    // Generate an identity tensor matching the shape of the global tensor and 
+    //  partition the same way, this will be used to generate the predicate
+    //  tensor for loading
+    Tensor cCol = make_identity_tensor(mCol.shape());
+    Tensor tCcCol = sm90_partition_for_epilogue<ReferenceSrc>(                         // (CPY,CPY_M,CPY_N,EPI_M,EPI_N)
+      cCol, args.tile_shape_mnk, args.tile_coord_mnkl, args.epi_tile, args.tiled_copy, args.thread_idx);
+
+    return ConsumerStoreCallbacks(
+      cute::move(tCgCol), 
+      cute::move(tCrCol), 
+      cute::move(tCcCol), 
+      args.problem_shape_mnkl, 
+      params
+    );
   }
 };