message: [XLA] Do not reserve large hash maps when there are many small computations.
diff: @@ -3470,12 +3470,7 @@ template <typename Visitor>
  static Status PostOrderDFS(HloInstruction* root, Visitor* visitor,
  const InternalCompareFunction* operand_order,
  bool ignore_control_predecessors) {
  - // Calculating the instruction count within a module can be expensive on large
  - // models so only do it if the visit state is empty. This will help when the
  - // same visitor is reused across many computations of a single module.
  - if (visitor->VisitStateCapacity() == 0) {
  - visitor->ReserveVisitStates(root->GetModule()->instruction_count());
  - }
  + visitor->ReserveVisitStates(root->parent()->instruction_count());
  // dfs_stack holds pairs of <HloInstruction*->unique_id(), HloInstruction*>.
  //
  