message: Add vlogging of HloModule before and after fusion.
diff: @@ -203,6 +203,9 @@ bool InstructionFusion::CanFuseOnAllPaths(
  }
  StatusOr<bool> InstructionFusion::Run(HloModule* module) {
  + VLOG(2) << "Before instruction fusion:";
  + XLA_VLOG_LINES(2, module->ToString());
  +
  bool changed = false;
  module_ = module;
  for (auto* computation : module->MakeNonfusionComputations()) {
  @@ -371,6 +374,10 @@ StatusOr<bool> InstructionFusion::Run(HloModule* module) {
  }
  }
  }
  +
  + VLOG(2) << "After instruction fusion:";
  + XLA_VLOG_LINES(2, module->ToString());
  +
  return changed;
  }
  