message: [XLA] Free Reachability Map before constructing a new one.
diff: @@ -30,10 +30,10 @@ StatusOr<bool> MultiOutputFusion::Run(HloModule* module) {
  for (auto* computation : module->MakeNonfusionComputations()) {
  computation_ = computation;
  - RecomputeReachability();
  candidates_.clear();
  candidates_index_.clear();
  all_fusion_candidates_.clear();
  + RecomputeReachability();
  int64 index = 0;
  for (auto it : computation_->MakeInstructionPostOrder()) {
  @@ -258,6 +258,8 @@ bool MultiOutputFusion::LegalToFuse(HloInstruction* instr1,
  }
  void MultiOutputFusion::RecomputeReachability() {
  + // Free the memory used for the reachability map before computing a new one.
  + reachability_.reset();
  reachability_ = HloReachabilityMap::Build(computation_);
  }
  