unsigned ReplicateOp::GetNumPackedBlockArguments() {
  return getPackedInputs().size();
}

// Returns the number of replicated block arguments.
unsigned ReplicateOp::GetNumReplicatedBlockArguments() {
  return GetBody().getNumArguments() - GetNumPackedBlockArguments();
}

// Returns the replicated block arguments. A copy should be made if the
// replicate op is being modified.

  llvm::SmallVector<Value, 8> new_packed_inputs;
  llvm::SmallVector<llvm::SmallVector<Value, 8>, 8> replicated_inputs;
  replicated_inputs.reserve(replicate.GetNumReplicatedBlockArguments());
  new_packed_inputs.reserve(replicate.GetNumPackedBlockArguments());
  for (const auto& arg : replicate.GetReplicatedBlockArguments()) {
    replicated_inputs.emplace_back();

           << ") 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.

  );

  let regions = (region SizedRegion<1>:$body);

  let extraClassDeclaration = [{
    Block &GetBody() { return getOperation()->getRegion(0).front(); }
    unsigned GetNumReplicatedBlockArguments();
    unsigned GetNumPackedBlockArguments();
    llvm::ArrayRef<BlockArgument> GetPackedBlockArguments();
    llvm::ArrayRef<BlockArgument> GetReplicatedBlockArguments();