message: [XLA] Skip AllReduceCombiner when threshold is 0
diff: @@ -268,6 +268,11 @@ StatusOr<bool> AllReduceCombiner::Run(HloModule* module) {
  VLOG(1) << "Running AllReduceCombiner with threshold of "
  << combine_threshold_in_bytes_ << " bytes";
  + if (combine_threshold_in_bytes_ <= 0 || combine_threshold_count_ <= 0) {
  + VLOG(1) << "Skip AllReduceCombiner because the threshold is zero";
  + return false;
  + }
  +
  if (hlo_query::ContainsLayoutConstrainedAllReduce(*module)) {
  VLOG(1) << "Skip AllReduceCombiner because the module contains all-reduce "
  "with constrained layouts";
  