[SimplifyCFG] Enable LastRunTrackingAnalysis for SimplifyCFGPass

llvm/include/llvm/Transforms/Scalar/SimplifyCFG.h

@@ -28,6 +28,7 @@ namespace llvm {
 /// it may further optimize control-flow to create non-canonical forms.
 class SimplifyCFGPass : public PassInfoMixin<SimplifyCFGPass> {
   SimplifyCFGOptions Options;
+  static char ID;
 
 public:
   /// The default constructor sets the pass options to create canonical IR,

llvm/include/llvm/Transforms/Utils/SimplifyCFGOptions.h

@@ -85,6 +85,22 @@ struct SimplifyCFGOptions {
     SpeculateUnpredictables = B;
     return *this;
   }
+
+  bool isCompatibleWith(const SimplifyCFGOptions &LastOptions) const {
+    return BonusInstThreshold == LastOptions.BonusInstThreshold &&
+           ForwardSwitchCondToPhi == LastOptions.ForwardSwitchCondToPhi &&
+           ConvertSwitchRangeToICmp == LastOptions.ConvertSwitchRangeToICmp &&
+           ConvertSwitchToLookupTable ==
+               LastOptions.ConvertSwitchToLookupTable &&
+           NeedCanonicalLoop == LastOptions.NeedCanonicalLoop &&
+           HoistCommonInsts == LastOptions.HoistCommonInsts &&
+           HoistLoadsStoresWithCondFaulting ==
+               LastOptions.HoistLoadsStoresWithCondFaulting &&
+           SinkCommonInsts == LastOptions.SinkCommonInsts &&
+           SimplifyCondBranch == LastOptions.SimplifyCondBranch &&
+           SpeculateBlocks == LastOptions.SpeculateBlocks &&
+           SpeculateUnpredictables == LastOptions.SpeculateUnpredictables;
+  }
 };
 
 } // namespace llvm

llvm/lib/Transforms/Scalar/SimplifyCFGPass.cpp

@@ -28,6 +28,7 @@
 #include "llvm/Analysis/CFG.h"
 #include "llvm/Analysis/DomTreeUpdater.h"
 #include "llvm/Analysis/GlobalsModRef.h"
+#include "llvm/Analysis/LastRunTrackingAnalysis.h"
 #include "llvm/Analysis/TargetTransformInfo.h"
 #include "llvm/IR/Attributes.h"
 #include "llvm/IR/CFG.h"
@@ -373,19 +374,31 @@ void SimplifyCFGPass::printPipeline(
 
 PreservedAnalyses SimplifyCFGPass::run(Function &F,
                                        FunctionAnalysisManager &AM) {
+  auto &LRT = AM.getResult<LastRunTrackingAnalysis>(F);
+  // No changes since last SimplifyCFGPass pass, exit early.
+  if (LRT.shouldSkip(&ID, Options))
+    return PreservedAnalyses::all();
+
   auto &TTI = AM.getResult<TargetIRAnalysis>(F);
   Options.AC = &AM.getResult<AssumptionAnalysis>(F);
   DominatorTree *DT = nullptr;
   if (RequireAndPreserveDomTree)
     DT = &AM.getResult<DominatorTreeAnalysis>(F);
-  if (!simplifyFunctionCFG(F, TTI, DT, Options))
+  if (!simplifyFunctionCFG(F, TTI, DT, Options)) {
+    LRT.update(&ID, /*Changed=*/false, Options);
     return PreservedAnalyses::all();
+  }
+
   PreservedAnalyses PA;
   if (RequireAndPreserveDomTree)
     PA.preserve<DominatorTreeAnalysis>();
+  LRT.update(&ID, /*Changed=*/true, Options);
+  PA.preserve<LastRunTrackingAnalysis>();
   return PA;
 }
 
+char SimplifyCFGPass::ID = 0;
+
 namespace {
 struct CFGSimplifyPass : public FunctionPass {
   static char ID;

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

@@ -104,6 +104,7 @@
 ; CHECK-O-NEXT: Running pass: EntryExitInstrumenterPass
 ; CHECK-O-NEXT: Running pass: LowerExpectIntrinsicPass
 ; CHECK-O-NEXT: Running pass: SimplifyCFGPass
+; CHECK-O-NEXT: Running analysis: LastRunTrackingAnalysis
 ; CHECK-O-NEXT: Running analysis: TargetIRAnalysis
 ; CHECK-O-NEXT: Running analysis: AssumptionAnalysis
 ; CHECK-O-NEXT: Running pass: SROAPass
@@ -118,7 +119,6 @@
 ; CHECK-O-NEXT: Running pass: GlobalOptPass
 ; CHECK-O-NEXT: Running pass: PromotePass
 ; CHECK-O-NEXT: Running pass: InstCombinePass
-; CHECK-O-NEXT: Running analysis: LastRunTrackingAnalysis
 ; CHECK-O-NEXT: Running analysis: OptimizationRemarkEmitterAnalysis
 ; CHECK-O-NEXT: Running analysis: AAManager
 ; CHECK-O-NEXT: Running analysis: BasicAA

llvm/test/Other/new-pm-thinlto-prelink-defaults.ll

@@ -73,6 +73,7 @@
 ; CHECK-O-NEXT: Running pass: EntryExitInstrumenterPass
 ; CHECK-O-NEXT: Running pass: LowerExpectIntrinsicPass
 ; CHECK-O-NEXT: Running pass: SimplifyCFGPass
+; CHECK-O-NEXT: Running analysis: LastRunTrackingAnalysis
 ; CHECK-O-NEXT: Running analysis: TargetIRAnalysis
 ; CHECK-O-NEXT: Running analysis: AssumptionAnalysis
 ; CHECK-O-NEXT: Running pass: SROAPass
@@ -86,7 +87,6 @@
 ; CHECK-O-NEXT: Running pass: GlobalOptPass
 ; CHECK-O-NEXT: Running pass: PromotePass
 ; CHECK-O-NEXT: Running pass: InstCombinePass
-; CHECK-O-NEXT: Running analysis: LastRunTrackingAnalysis
 ; CHECK-O-NEXT: Running analysis: OptimizationRemarkEmitterAnalysis
 ; CHECK-O-NEXT: Running analysis: AAManager
 ; CHECK-O-NEXT: Running analysis: BasicAA

llvm/test/Other/new-pm-thinlto-prelink-pgo-defaults.ll

@@ -37,6 +37,7 @@
 ; CHECK-O-NEXT: Running pass: EntryExitInstrumenterPass
 ; CHECK-O-NEXT: Running pass: LowerExpectIntrinsicPass
 ; CHECK-O-NEXT: Running pass: SimplifyCFGPass
+; CHECK-O-NEXT: Running analysis: LastRunTrackingAnalysis
 ; CHECK-O-NEXT: Running analysis: TargetIRAnalysis
 ; CHECK-O-NEXT: Running analysis: AssumptionAnalysis
 ; CHECK-O-NEXT: Running pass: SROAPass
@@ -50,7 +51,6 @@
 ; CHECK-O-NEXT: Running pass: GlobalOptPass
 ; CHECK-O-NEXT: Running pass: PromotePass
 ; CHECK-O-NEXT: Running pass: InstCombinePass
-; CHECK-O-NEXT: Running analysis: LastRunTrackingAnalysis
 ; CHECK-O-NEXT: Running analysis: OptimizationRemarkEmitterAnalysis
 ; CHECK-O-NEXT: Running analysis: AAManager
 ; CHECK-O-NEXT: Running analysis: BasicAA
@@ -122,8 +122,8 @@
 ; CHECK-O23SZ-NEXT: Running pass: CorrelatedValuePropagationPass
 ; CHECK-O23SZ-NEXT: Invalidating analysis: LazyValueAnalysis
 ; CHECK-O-NEXT: Running pass: SimplifyCFGPass
-; CHECK-O-NEXT: Running pass: InstCombinePass
 ; CHECK-O-NEXT: Running analysis: LastRunTrackingAnalysis
+; CHECK-O-NEXT: Running pass: InstCombinePass
 ; CHECK-O-NEXT: Running analysis: BlockFrequencyAnalysis on foo
 ; CHECK-O-NEXT: Running analysis: BranchProbabilityAnalysis on foo
 ; CHECK-O-NEXT: Running analysis: LoopAnalysis on foo

llvm/test/Other/new-pm-thinlto-prelink-samplepgo-defaults.ll

@@ -36,6 +36,7 @@
 ; CHECK-O-NEXT: Running pass: EntryExitInstrumenterPass
 ; CHECK-O-NEXT: Running pass: LowerExpectIntrinsicPass
 ; CHECK-O-NEXT: Running pass: SimplifyCFGPass
+; CHECK-O-NEXT: Running analysis: LastRunTrackingAnalysis
 ; CHECK-O-NEXT: Running analysis: TargetIRAnalysis
 ; CHECK-O-NEXT: Running analysis: AssumptionAnalysis
 ; CHECK-O-NEXT: Running pass: SROAPass
@@ -53,7 +54,6 @@
 ; CHECK-O-NEXT: Running pass: GlobalOptPass
 ; CHECK-O-NEXT: Running pass: PromotePass
 ; CHECK-O-NEXT: Running pass: InstCombinePass
-; CHECK-O-NEXT: Running analysis: LastRunTrackingAnalysis
 ; CHECK-O-NEXT: Running analysis: OptimizationRemarkEmitterAnalysis on foo
 ; CHECK-O-NEXT: Running analysis: AAManager on foo
 ; CHECK-O-NEXT: Running analysis: BasicAA

llvm/unittests/IR/PassManagerTest.cpp

@@ -8,6 +8,7 @@
 
 #include "llvm/IR/PassManager.h"
 #include "llvm/Analysis/AssumptionCache.h"
+#include "llvm/Analysis/LastRunTrackingAnalysis.h"
 #include "llvm/Analysis/TargetTransformInfo.h"
 #include "llvm/AsmParser/Parser.h"
 #include "llvm/IR/Dominators.h"
@@ -835,6 +836,7 @@ TEST_F(PassManagerTest, FunctionPassCFGChecker) {
   FAM.registerPass([&] { return DominatorTreeAnalysis(); });
   FAM.registerPass([&] { return AssumptionAnalysis(); });
   FAM.registerPass([&] { return TargetIRAnalysis(); });
+  FAM.registerPass([&] { return LastRunTrackingAnalysis(); });
 
   FPM.addPass(SimplifyCFGPass());
   FPM.run(*F, FAM);
@@ -884,6 +886,7 @@ TEST_F(PassManagerTest, FunctionPassCFGCheckerInvalidateAnalysis) {
   FAM.registerPass([&] { return DominatorTreeAnalysis(); });
   FAM.registerPass([&] { return AssumptionAnalysis(); });
   FAM.registerPass([&] { return TargetIRAnalysis(); });
+  FAM.registerPass([&] { return LastRunTrackingAnalysis(); });
 
   FPM.addPass(TestSimplifyCFGInvalidatingAnalysisPass());
   FPM.run(*F, FAM);
@@ -952,6 +955,7 @@ TEST_F(PassManagerTest, FunctionPassCFGCheckerWrapped) {
   FAM.registerPass([&] { return DominatorTreeAnalysis(); });
   FAM.registerPass([&] { return AssumptionAnalysis(); });
   FAM.registerPass([&] { return TargetIRAnalysis(); });
+  FAM.registerPass([&] { return LastRunTrackingAnalysis(); });
 
   FunctionPassManager InnerFPM;
   InnerFPM.addPass(SimplifyCFGPass());