message: [XLA:TF] Explain why we're not doing sum reductions in 16 bit
diff: @@ -303,6 +303,8 @@ Status XlaHelpers::OneHot(xla::XlaBuilder* builder, int64 depth, int axis,
  }
  DataType XlaHelpers::SumAccumulationType(const DataType& dtype) {
  + // Upcast 16 bit sum reductions to 32 bit to reduce the precision loss from
  + // repeated floating point additions.
  if (dtype == DT_BFLOAT16 || dtype == DT_HALF) {
  return DT_FLOAT;
  }
  