message: FIFOs with no users should be removable
  Summary: Fixes T18098
  Reviewers: #tensorflow, #framework_ip_review_-_any_oss_or_third-party_code_use_has_been_approved, davidn
  Subscribers: davidn
  Maniphest Tasks: T18098
diff: @@ -14,6 +14,7 @@ limitations under the License.
  ==============================================================================*/
  #include "tensorflow/compiler/plugin/poplar/driver/tools/custom_ops/fifo.h"
  +
  #include "tensorflow/compiler/plugin/poplar/kernels/custom_kernels_util.h"
  #include "tensorflow/compiler/plugin/poplar/kernels/ops.pb.h"
  @@ -22,9 +23,7 @@ namespace poplarplugin {
  HloFifoInstruction::HloFifoInstruction(HloInstruction* operand, int64 depth)
  : HloPoplarInstruction(operand->shape(), {operand}, PoplarOp::Fifo, depth),
  - depth_(depth) {
  - set_custom_call_has_side_effect(true);
  -}
  + depth_(depth) {}
  const HloInstruction* HloFifoInstruction::input() const { return operand(0); }
  