message: Don't overwrite the output of the body if it is a constant
diff: @@ -230,8 +230,10 @@ CreateWhileOp(poplar::Graph &graph,
  poplar::program::Sequence main_seq;
  for (unsigned int i=0; i<param_count; i++) {
  + if (body_outputs[i].isParallelWriteable()) {
  main_seq.add(poplar::program::Copy(inits[i], body_outputs[i]));
  }
  + }
  // Body
  poplar::program::Sequence body_seq;
  