Allow scalar broadcasting in VisitorRowBroadcast and VisitorColBroadcast

Author: tlrmchlsmth

include/cutlass/epilogue/threadblock/fusion/visitor_load.hpp

@@ -403,10 +403,29 @@ struct VisitorRowBroadcast {
       auto src_v = filter(tC_gRow);
       auto coord_v = filter(tC_cRow);
       auto dst_v = filter(tC_rRow);
-      CUTLASS_PRAGMA_UNROLL
-      for (int i = 0; i < size(src_v); ++i) {
-        bool guard = get<1>(coord_v(i)) < n;
-        cutlass::arch::global_load<VecType, sizeof(VecType)>(dst_v(i), (void const*)&src_v(i), guard);
+
+      if (params_ptr->ptr_row) {
+        // In this case we are loading from a row vector and broadcasting
+        CUTLASS_PRAGMA_UNROLL
+        for (int i = 0; i < size(src_v); ++i) {
+          bool guard = get<1>(coord_v(i)) < n;
+          cutlass::arch::global_load<VecType, sizeof(VecType)>(dst_v(i), (void const*)&src_v(i), guard);
+        }
+      } else {
+        // In this case we are loading from a scalar and broadcasting
+        VecType filled_vec;
+        CUTLASS_PRAGMA_UNROLL
+        for (int i = 0; i < VecLength; i++) {
+          reinterpret_cast<Element*>(&filled_vec)[i] = params_ptr->null_default;
+        }
+
+        CUTLASS_PRAGMA_UNROLL
+        for (int i = 0; i < size(src_v); ++i) {
+          if(get<1>(coord_v(i)) < n)
+          {
+            dst_v(i) = filled_vec;
+          }
+        }
       }
     }
 
@@ -524,12 +543,27 @@ struct VisitorColBroadcast {
     CUTLASS_DEVICE void
     begin_epilogue() {
       clear(tC_rCol);
+
       Tensor pred = make_tensor<bool>(shape(tC_gCol));
       CUTLASS_PRAGMA_UNROLL
       for (int i = 0; i < size(pred); ++i) {
         pred(i) = get<0>(tC_cCol(i)) < m;
       }
-      copy_if(pred, tC_gCol, tC_rCol);
+
+      if (params_ptr->ptr_col) {
+        // In this case we are loading from a column vector and broadcasting
+        copy_if(pred, tC_gCol, tC_rCol);
+      } else {
+        // In this case we are loading from a scalar and broadcasting
+        auto dst_v = filter(tC_rCol);
+
+        CUTLASS_PRAGMA_UNROLL
+        for (int i = 0; i < size(dst_v); ++i) {
+          if(pred(i)){
+             dst_v(i) = params_ptr->null_default;
+          }
+        }
+      }
     }
 
     template <class ElementAccumulator, int FragmentSize>