[PM] Add Argument Promotion to the pass pipeline.

[chandlerc]

Summary

This needs explicit requires of the optimization remark emission before
loop pass pipelines containing LICM as we no longer get it from the
inliner -- Argument Promotion may invalidate it. Technically the inliner
could also have broken this, but it never came up in testing.

Depends on D29580.

[davide]

LGTM once the other patches go in

lib/Passes/PassBuilder.cpp

#if 0
   // The LoopUnswitch pass isn't yet ported to the new pass manager.
   LPM1.addPass(LoopUnswitchPass(/* OptimizeForSize */ Level != O3));
 #endif
   LPM2.addPass(IndVarSimplifyPass());
   LPM2.addPass(LoopIdiomRecognizePass());
   LPM2.addPass(LoopDeletionPass());
   LPM2.addPass(LoopUnrollPass::createFull());
 
+  // We provide the opt remark emitter pass for LICM to use. We only need to do
+  // this once as it is immutable.
+  FPM.addPass(RequireAnalysisPass<OptimizationRemarkEmitterAnalysis, Function>());
   FPM.addPass(createFunctionToLoopPassAdaptor(std::move(LPM1)));
   FPM.addPass(SimplifyCFGPass());
   FPM.addPass(InstCombinePass());
   FPM.addPass(createFunctionToLoopPassAdaptor(std::move(LPM2)));
 
   // Eliminate redundancies.
   if (Level != O1) {
     // These passes add substantial compile time so skip them at O1.
#endif
   // the callees have already been fully optimized, and we want to inline them
   // into the callers so that our optimizations can reflect that.
   // FIXME; Customize the threshold based on optimization level.
   MainCGPipeline.addPass(InlinerPass());
 
   // 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 == O3)
+    MainCGPipeline.addPass(ArgumentPromotionPass());
+
   // Lastly, add the core function simplification pipeline nested inside the
   // CGSCC walk.
   MainCGPipeline.addPass(createCGSCCToFunctionPassAdaptor(
       buildFunctionSimplificationPipeline(Level, DebugLogging)));
 
   MPM.addPass(
       createModuleToPostOrderCGSCCPassAdaptor(std::move(MainCGPipeline)));
 
#endif
   // Unroll small loops to hide loop backedge latency and saturate any parallel
   // execution resources of an out-of-order processor. We also then need to
   // clean up redundancies and loop invariant code.
   // FIXME: It would be really good to use a loop-integrated instruction
   // combiner for cleanup here so that the unrolling and LICM can be pipelined
   // across the loop nests.
   OptimizePM.addPass(createFunctionToLoopPassAdaptor(LoopUnrollPass::create()));
   OptimizePM.addPass(InstCombinePass());
+  OptimizePM.addPass(RequireAnalysisPass<OptimizationRemarkEmitterAnalysis, Function>());
   OptimizePM.addPass(createFunctionToLoopPassAdaptor(LICMPass()));
 
   // Now that we've vectorized and unrolled loops, we may have more refined
   // alignment information, try to re-derive it here.
   OptimizePM.addPass(AlignmentFromAssumptionsPass());
 
   // LoopSink pass sinks instructions hoisted by LICM, which serves as a
   // canonicalization pass that enables other optimizations. As a result,

test/Other/new-pm-defaults.ll

 ; CHECK-O-NEXT: Running analysis: InnerAnalysisManagerProxy
 ; CHECK-O-NEXT: Running analysis: LazyCallGraphAnalysis
 ; CHECK-O-NEXT: Starting CGSCC pass manager run.
 ; CHECK-O-NEXT: Running pass: InlinerPass
 ; CHECK-O-NEXT: Running analysis: OuterAnalysisManagerProxy<{{.*}}LazyCallGraph{{.*}}>
 ; CHECK-O-NEXT: Running analysis: FunctionAnalysisManagerCGSCCProxy
 ; CHECK-O-NEXT: Running analysis: OptimizationRemarkEmitterAnalysis
 ; CHECK-O-NEXT: Running pass: PostOrderFunctionAttrsPass
+; CHECK-O3-NEXT: Running pass: ArgumentPromotionPass
 ; CHECK-O-NEXT: Running pass: CGSCCToFunctionPassAdaptor<{{.*}}PassManager{{.*}}>
 ; CHECK-O-NEXT: Starting llvm::Function pass manager run.
 ; CHECK-O-NEXT: Running pass: SROA
 ; CHECK-O-NEXT: Running pass: EarlyCSEPass
 ; CHECK-O-NEXT: Running pass: SpeculativeExecutionPass
 ; CHECK-O-NEXT: Running pass: JumpThreadingPass
 ; CHECK-O-NEXT: Running analysis: LazyValueAnalysis
 ; CHECK-O-NEXT: Running pass: CorrelatedValuePropagationPass
 ; CHECK-O-NEXT: Running pass: SimplifyCFGPass
 ; CHECK-O-NEXT: Running pass: InstCombinePass
 ; CHECK-O1-NEXT: Running pass: LibCallsShrinkWrapPass
 ; CHECK-O2-NEXT: Running pass: LibCallsShrinkWrapPass
 ; CHECK-O3-NEXT: Running pass: LibCallsShrinkWrapPass
 ; CHECK-O-NEXT: Running pass: TailCallElimPass
 ; CHECK-O-NEXT: Running pass: SimplifyCFGPass
 ; CHECK-O-NEXT: Running pass: ReassociatePass
+; CHECK-O-NEXT: Running pass: RequireAnalysisPass<{{.*}}OptimizationRemarkEmitterAnalysis
 ; CHECK-O-NEXT: Running pass: FunctionToLoopPassAdaptor<{{.*}}LoopStandardAnalysisResults{{.*}}>
 ; CHECK-O-NEXT: Running analysis: LoopAnalysis
 ; CHECK-O-NEXT: Running analysis: InnerAnalysisManagerProxy
 ; CHECK-O-NEXT: Running analysis: ScalarEvolutionAnalysis
 ; CHECK-O-NEXT: Starting Loop pass manager run.
 ; CHECK-O-NEXT: Running pass: LoopRotatePass
 ; CHECK-O-NEXT: Running pass: LICM
 ; CHECK-O-NEXT: Running analysis: OuterAnalysisManagerProxy

 ; CHECK-O-NEXT: Running pass: LoopLoadEliminationPass
 ; CHECK-O-NEXT: Running analysis: LoopAccessAnalysis
 ; CHECK-O-NEXT: Running pass: InstCombinePass
 ; CHECK-O-NEXT: Running pass: SLPVectorizerPass
 ; CHECK-O-NEXT: Running pass: SimplifyCFGPass
 ; CHECK-O-NEXT: Running pass: InstCombinePass
 ; CHECK-O-NEXT: Running pass: FunctionToLoopPassAdaptor<{{.*}}LoopUnrollPass
 ; CHECK-O-NEXT: Running pass: InstCombinePass
+; CHECK-O-NEXT: Running pass: RequireAnalysisPass<{{.*}}OptimizationRemarkEmitterAnalysis
 ; CHECK-O-NEXT: Running pass: FunctionToLoopPassAdaptor<{{.*}}LICMPass
 ; CHECK-O-NEXT: Running pass: AlignmentFromAssumptionsPass
 ; CHECK-O-NEXT: Running pass: LoopSinkPass
 ; CHECK-O-NEXT: Running pass: InstSimplifierPass
 ; CHECK-O-NEXT: Finished llvm::Function pass manager run.
 ; CHECK-O-NEXT: Running pass: GlobalDCEPass
 ; CHECK-O-NEXT: Running pass: ConstantMergePass
 ; CHECK-O-NEXT: Finished llvm::Module pass manager run.