message: Add a little bit of extra info to the error
diff: @@ -408,7 +408,7 @@ Status BaseVisitor::HandleCall(HloInstruction* inst) {
  else {
  return port::Status(port::error::FAILED_PRECONDITION,
  port::StrCat("Unrecognized special call op ",
  - inst->name()));
  + inst->name(), ": ", name));
  }
  } else {
  poplar::program::Program prog;
  