<< ") to append to replicate to be num_replicas ("
           << replicate.getN() << ")";
  }

  // add block arg to region. This is in $body.
  unsigned block_arg_idx = replicate.GetNumReplicatedBlockArguments();
  Block& block = replicate.GetBody();
  block_arg = block.insertArgument(block_arg_idx, type, replicate.getLoc());

  // add to $replicated_inputs. This also updates OperandSegmentSizeAttr.