first_index = last_index;
      continue;
    }
    if (last_index + 1 != ind.getSExtValue()) return -1;
    last_index++;
  }
  return first_index;
}

}  // namespace

Value GatherElements(Value indices, Value buffer, OpBuilder builder,
                     Location loc) {
  auto buffer_type = mlir::cast<RankedTensorType>(buffer.getType());
  auto result_shape = llvm::to_vector<8>(buffer_type.getShape());

  auto it = buffer_to_size.find(gather.getInputHandle());
  if (it == buffer_to_size.end()) {
    return gather.emitOpError("unknown tensor list");
  }
  auto buffer = gather.getInputHandle();
  auto result = cutil::GatherElements(gather.getIndices(), buffer,
                                      OpBuilder(gather), gather.getLoc());
  gather.getValues().replaceAllUsesWith(result);
  gather.erase();
  return success();
}