[NewPM] Add missing LTO ArgPromotion pass

[nikic]

Summary

This is a followup to D96780 to add one more pass missing from the NewPM LTO pipeline. The missing ArgPromotion run is inserted at the same position as in the LegacyPM (https://github.com/llvm/llvm-project/blob/16086d47c0d0cd08ffae8e69a69c88653e654d01/llvm/lib/Transforms/IPO/PassManagerBuilder.cpp#L1096-L1098), which resolves the already present TODO.

The compile-time impact is minimal: https://llvm-compile-time-tracker.com/compare.php?from=16086d47c0d0cd08ffae8e69a69c88653e654d01&to=90de51b3dfb00239941f00b0eeaa7fc78db2f8b8&stat=instructions

I believe this resolves the last blocker for the NewPM migration in rustc...

[aeubanks]

lgtm

llvm/lib/Passes/PassBuilder.cpp

PassBuilder::buildLTODefaultPipeline(OptimizationLevel Level,
   // invoke or a call.
   // Run the inliner now.
   MPM.addPass(ModuleInlinerWrapperPass(getInlineParamsFromOptLevel(Level)));
 
   // Optimize globals again after we ran the inliner.
   MPM.addPass(GlobalOptPass());
 
   // Garbage collect dead functions.
-  // FIXME: Add ArgumentPromotion pass after once it's ported.
   MPM.addPass(GlobalDCEPass());
 
+  // If we didn't decide to inline a function, check to see if we can
+  // transform it to pass arguments by value instead of by reference.
+  MPM.addPass(createModuleToPostOrderCGSCCPassAdaptor(ArgumentPromotionPass()));
+
   FunctionPassManager FPM;
   // The IPO Passes may leave cruft around. Clean up after them.
   FPM.addPass(InstCombinePass());
   invokePeepholeEPCallbacks(FPM, Level);
 
   FPM.addPass(JumpThreadingPass(/*InsertFreezeWhenUnfoldingSelect*/ true));
 
   // Do a post inline PGO instrumentation and use pass. This is a context

llvm/test/Other/new-pm-lto-defaults.ll

 ; CHECK-O23SZ-NEXT: Running pass: InstCombinePass
 ; CHECK-EP-Peephole-NEXT: Running pass: NoOpFunctionPass
 ; CHECK-O23SZ-NEXT: Running pass: ModuleInlinerWrapperPass
 ; CHECK-O23SZ-NEXT: Running analysis: InlineAdvisorAnalysis
 ; CHECK-O23SZ-NEXT: Running pass: InlinerPass
 ; CHECK-O23SZ-NEXT: Running pass: InlinerPass
 ; CHECK-O23SZ-NEXT: Running pass: GlobalOptPass
 ; CHECK-O23SZ-NEXT: Running pass: GlobalDCEPass
+; CHECK-O23SZ-NEXT: Running pass: ArgumentPromotionPass
 ; CHECK-O23SZ-NEXT: Running pass: InstCombinePass
 ; CHECK-EP-Peephole-NEXT: Running pass: NoOpFunctionPass
 ; CHECK-O23SZ-NEXT: Running pass: JumpThreadingPass
 ; CHECK-O23SZ-NEXT: Running analysis: LazyValueAnalysis
 ; CHECK-O23SZ-NEXT: Running pass: SROA on foo
 ; CHECK-O23SZ-NEXT: Running pass: TailCallElimPass on foo
 ; CHECK-O23SZ-NEXT: Running pass: PostOrderFunctionAttrsPass on (foo)
 ; CHECK-O23SZ-NEXT: Running pass: RequireAnalysisPass<{{.*}}GlobalsAA