if (!HasRankAtLeast(op.getOutBackprop(), 2))
      return op.emitOpError(
          "requires out_backprop operand to have rank at least two with `NHWC` "
          "data format");
  } else {
    // Op definition requires data_format to be either NHWC or NCHW.
    DCHECK_EQ(format, tensorflow::TensorFormat::FORMAT_NCHW);
    if (!HasRankAtLeast(op.getOutBackprop(), 3))
      return op.emitOpError(