// to the list of return values. Returns the mapping from the buffer
// indices to the added size indices, which is a list of tuples
// (buffer_return_index, size_return_index, fixed_size).
template <class TerminatorOp>
llvm::SmallVector<std::tuple<int64_t, int64_t, bool>, 8>
AddTensorListSizesToTerminator(
    Block& block, const llvm::SmallDenseMap<Value, SizeInfo>& buffer_to_size) {
  auto old_terminator = block.getTerminator();