message: Use the new poplar clone tensor interface
diff: @@ -105,11 +105,7 @@ CreateCallOp(poplar::Graph &graph,
  seq.add(visitor->second.sequence);
  for (size_t i=0; i<visitor->second.outputs().size(); i++) {
  - // TODO use 'clone' when poplar supports it
  - poplar::Tensor o = graph.addTensor(
  - visitor->second.outputs()[i].elementType(),
  - visitor->second.outputs()[i].shape());
  - popstd::mapTensor(graph, o);
  + poplar::Tensor o = graph.clone(visitor->second.outputs()[i]);
  seq.add(poplar::program::Copy(visitor->second.outputs()[i], o));
  TF_RETURN_IF_ERROR(AddOutputTensor(tensor_map, inst, i, o));
  }
  @@ -172,10 +168,7 @@ CreateWhileOp(poplar::Graph &graph,
  main_seq.add(repeat_while_true);
  - // TODO use 'clone' when poplar supports it
  - poplar::Tensor o = graph.addTensor(body_output.elementType(),
  - body_output.shape());
  - popstd::mapTensor(graph, o);
  + poplar::Tensor o = graph.clone(body_output);
  main_seq.add(poplar::program::Copy(body_output, o));
  TF_RETURN_IF_ERROR(AddOutputTensor(tensor_map, inst, 0, o));
  