message: shrink peak memory consumptio with -tv-save-ir
diff: @@ -671,8 +671,10 @@ llvmGetPassPluginInfo() {
  else if (is_first)
  TVPass::batched_pass_begin_name = "beginning";
  - if ((is_first || do_start) && opt_save_ir)
  + if ((is_first || do_start) && opt_save_ir) {
  + MClone.reset();
  MClone = llvm::CloneModule(*unwrapModule(IR));
  + }
  if (is_first || do_start || do_finish)
  runTVPass(*const_cast<llvm::Module *>(unwrapModule(IR)));
  @@ -689,6 +691,7 @@ llvmGetPassPluginInfo() {
  PB.getPassInstrumentationCallbacks()
  ->registerBeforeNonSkippedPassCallback(
  [](llvm::StringRef P, llvm::Any IR) {
  + MClone.reset();
  MClone = llvm::CloneModule(*unwrapModule(IR));
  });
  }
  