message: Log Hlo IR when compiling for CPU
diff: @@ -457,8 +457,14 @@ StatusOr<std::unique_ptr<Executable>> CpuCompiler::Compile(
  llvm_module->setDataLayout(jit->data_layout());
  llvm_module->setTargetTriple(jit->target_triple().getTriple());
  + VLOG(2) << "Before optimization:";
  + XLA_VLOG_LINES(2, module->ToString());
  +
  TF_RETURN_IF_ERROR(RunHloPasses(module.get(), /*is_aot_compile=*/false));
  + VLOG(2) << "After optimization:";
  + XLA_VLOG_LINES(2, module->ToString());
  +
  HloComputation* computation = module->entry_computation();
  std::unordered_map<const HloInstruction*, size_t> hlo_to_profile_idx;
  if (module->config().hlo_profiling_enabled()) {
  