message: Remove TODO due to this function is specified as 4D now.
  This comment was added when this function is BroadcastAdd.
diff: @@ -202,10 +202,6 @@ inline void Add(const ArithmeticParams& params,
  }
  }
  -// TODO(jiawen): We can implement BroadcastAdd on buffers of arbitrary
  -// dimensionality if the runtime code does a single loop over one dimension
  -// that handles broadcasting as the base case. The code generator would then
  -// generate max(D1, D2) nested for loops.
  inline void BroadcastAdd4DSlow(const ArithmeticParams& params,
  const RuntimeShape& input1_shape,
  const float* input1_data,
  