return errors::Unimplemented(
        "BroadcastMul is not supported in tracing mode yet.");
  }
  auto imm_ctx = dyn_cast<ImmediateExecutionContext>(ctx);
  AbstractTensorPtr minus_1(imm_ctx->CreateInt32Scalar(-1));
  ImmediateTensorHandlePtr dim(imm_ctx->CreateLocalHandle(minus_1.get()));
  AbstractTensorHandle* expand_dims_outputs;
  TF_RETURN_IF_ERROR(
      ops::ExpandDims(ctx, vec, dim.get(), &expand_dims_outputs, "ExpandDims"));

    name = "Neg_Div_Grad_Y";
    TF_RETURN_IF_ERROR(Neg(ctx, upstream_grad, &temp_output,
                           name.c_str()));  // -U
    AbstractTensorHandlePtr MinusU(temp_output);

    name = "Mul_Div_Grad_Y";
    TF_RETURN_IF_ERROR(Mul(ctx, MinusU.get(), Z, &temp_output,
                           name.c_str()));  // -U*Z
    AbstractTensorHandlePtr UZ(temp_output);

    name = "Div_Grad_Y";

Jonas Meinertz Hansen, Joshi Rekha, Julian Viereck, Keiji Ariyama, Kenton Lee,
Krishna Sankar, Kristina Chodorow, Linchao Zhu, Lukas Krecan, Mark Borgerding,
Mark Daoust, Moussa Taifi, Nathan Howell, Naveen Sundar Govindarajulu, Nick
Sweeting, Niklas Riekenbrauck, Olivier Grisel, Patrick Christ, Povilas
Liubauskas, Rainer Wasserfuhr, Romain Thouvenin, Sagan Bolliger, Sam Abrahams,