Run Attributor/FuncAttrs after function simplification

[aeubanks]

(not for review)

llvm/lib/Passes/PassBuilder.cpp

PassBuilder::buildInlinerPipeline(OptimizationLevel Level,
   MIWP.addRequiredModuleAnalysis<ProfileSummaryAnalysis>();
 
   // Now begin the main postorder CGSCC pipeline.
   // FIXME: The current CGSCC pipeline has its origins in the legacy pass
   // manager and trying to emulate its precise behavior. Much of this doesn't
   // make a lot of sense and we should revisit the core CGSCC structure.
   CGSCCPassManager &MainCGPipeline = MIWP.getPM();
 
-  // Note: historically, the PruneEH pass was run first to deduce nounwind and
-  // generally clean up exception handling overhead. It isn't clear this is
-  // valuable as the inliner doesn't currently care whether it is inlining an
-  // invoke or a call.
-
-  if (AttributorRun & AttributorRunOption::CGSCC)
-    MainCGPipeline.addPass(AttributorCGSCCPass());
-
   if (PTO.Coroutines)
     MainCGPipeline.addPass(CoroSplitPass(Level != OptimizationLevel::O0));
 
-  // Now deduce any function attributes based in the current code.
-  MainCGPipeline.addPass(PostOrderFunctionAttrsPass());
-
   // When at O3 add argument promotion to the pass pipeline.
   // FIXME: It isn't at all clear why this should be limited to O3.
   if (Level == OptimizationLevel::O3)
     MainCGPipeline.addPass(ArgumentPromotionPass());
 
   // Try to perform OpenMP specific optimizations. This is a (quick!) no-op if
   // there are no OpenMP runtime calls present in the module.
   if (Level == OptimizationLevel::O2 || Level == OptimizationLevel::O3)
     MainCGPipeline.addPass(OpenMPOptPass());
 
   for (auto &C : CGSCCOptimizerLateEPCallbacks)
     C(MainCGPipeline, Level);
 
   // Lastly, add the core function simplification pipeline nested inside the
   // CGSCC walk.
   MainCGPipeline.addPass(createCGSCCToFunctionPassAdaptor(
       buildFunctionSimplificationPipeline(Level, Phase)));
 
+  if (AttributorRun & AttributorRunOption::CGSCC)
+    MainCGPipeline.addPass(AttributorCGSCCPass());
+
+  // Now deduce any function attributes based in the current code.
+  MainCGPipeline.addPass(PostOrderFunctionAttrsPass());
+
   return MIWP;
 }
 
 ModulePassManager
 PassBuilder::buildModuleSimplificationPipeline(OptimizationLevel Level,
                                                ThinOrFullLTOPhase Phase) {
   ModulePassManager MPM(DebugLogging);
 

llvm/lib/Transforms/IPO/PassManagerBuilder.cpp

void PassManagerBuilder::populateModulePassManager(
   MPM.add(createPruneEHPass()); // Remove dead EH info
   bool RunInliner = false;
   if (Inliner) {
     MPM.add(Inliner);
     Inliner = nullptr;
     RunInliner = true;
   }
 
-  // Infer attributes on declarations, call sites, arguments, etc. for an SCC.
-  if (AttributorRun & AttributorRunOption::CGSCC)
-    MPM.add(createAttributorCGSCCLegacyPass());
-
   // Try to perform OpenMP specific optimizations. This is a (quick!) no-op if
   // there are no OpenMP runtime calls present in the module.
   if (OptLevel > 1)
     MPM.add(createOpenMPOptLegacyPass());
 
-  MPM.add(createPostOrderFunctionAttrsLegacyPass());
   if (OptLevel > 2)
     MPM.add(createArgumentPromotionPass()); // Scalarize uninlined fn args
 
   addExtensionsToPM(EP_CGSCCOptimizerLate, MPM);
   addFunctionSimplificationPasses(MPM);
 
+  // Infer attributes on declarations, call sites, arguments, etc. for an SCC.
+  if (AttributorRun & AttributorRunOption::CGSCC)
+    MPM.add(createAttributorCGSCCLegacyPass());
+
+  MPM.add(createPostOrderFunctionAttrsLegacyPass());
+
   // FIXME: This is a HACK! The inliner pass above implicitly creates a CGSCC
   // pass manager that we are specifically trying to avoid. To prevent this
   // we must insert a no-op module pass to reset the pass manager.
   MPM.add(createBarrierNoopPass());
 
   if (RunPartialInlining)
     MPM.add(createPartialInliningPass());