[NewPM][LoopVersioning] Port LoopVersioning to NPM

[ychen]

Add a test case in llvm/test/Transforms/LoopVersioning/basic.ll? Where is the unit test for this (if there is any)?

llvm/lib/Transforms/Utils/LoopVersioning.cpp

259

use function_ref since it is a one-time use/ref of a callable.

275

delete

365

extra brace

[aeubanks]

Address review comments

[ychen]

LGTM

llvm/lib/Transforms/Utils/LoopVersioning.cpp

301–305

format?

[aeubanks]

clang-format

[fhahn]

Thanks for porting this! LGTM

llvm/include/llvm/InitializePasses.h

 void initializeLoopSimplifyCFGLegacyPassPass(PassRegistry&);
 void initializeLoopSimplifyPass(PassRegistry&);
 void initializeLoopStrengthReducePass(PassRegistry&);
 void initializeLoopUnrollAndJamPass(PassRegistry&);
 void initializeLoopUnrollPass(PassRegistry&);
 void initializeLoopUnswitchPass(PassRegistry&);
 void initializeLoopVectorizePass(PassRegistry&);
 void initializeLoopVersioningLICMPass(PassRegistry&);
-void initializeLoopVersioningPassPass(PassRegistry&);
+void initializeLoopVersioningLegacyPassPass(PassRegistry &);
 void initializeLowerAtomicLegacyPassPass(PassRegistry&);
 void initializeLowerConstantIntrinsicsPass(PassRegistry&);
 void initializeLowerEmuTLSPass(PassRegistry&);
 void initializeLowerExpectIntrinsicPass(PassRegistry&);
 void initializeLowerGuardIntrinsicLegacyPassPass(PassRegistry&);
 void initializeLowerWidenableConditionLegacyPassPass(PassRegistry&);
 void initializeLowerIntrinsicsPass(PassRegistry&);
 void initializeLowerInvokeLegacyPassPass(PassRegistry&);

llvm/include/llvm/Transforms/Utils/LoopVersioning.h

 // emits checks to prove this.
 //
 //===----------------------------------------------------------------------===//
 
 #ifndef LLVM_TRANSFORMS_UTILS_LOOPVERSIONING_H
 #define LLVM_TRANSFORMS_UTILS_LOOPVERSIONING_H
 
 #include "llvm/Analysis/ScalarEvolution.h"
+#include "llvm/IR/PassManager.h"
 #include "llvm/Transforms/Utils/LoopUtils.h"
 #include "llvm/Transforms/Utils/ValueMapper.h"
 
 namespace llvm {
 
 class Loop;
 class LoopAccessInfo;
 class LoopInfo;
DenseMap<const RuntimeCheckingPtrGroup *, MDNode *>
       GroupToNonAliasingScopeList;
 
   /// Analyses used.
   const LoopAccessInfo &LAI;
   LoopInfo *LI;
   DominatorTree *DT;
   ScalarEvolution *SE;
 };
+
+/// Expose LoopVersioning as a pass.  Currently this is only used for
+/// unit-testing.  It adds all memchecks necessary to remove all may-aliasing
+/// array accesses from the loop.
+class LoopVersioningPass : public PassInfoMixin<LoopVersioningPass> {
+public:
+  PreservedAnalyses run(Function &F, FunctionAnalysisManager &FAM);
+};
 }
 
 #endif

llvm/lib/Passes/PassBuilder.cpp

 #include "llvm/Transforms/Utils/BreakCriticalEdges.h"
 #include "llvm/Transforms/Utils/CanonicalizeAliases.h"
 #include "llvm/Transforms/Utils/CanonicalizeFreezeInLoops.h"
 #include "llvm/Transforms/Utils/EntryExitInstrumenter.h"
 #include "llvm/Transforms/Utils/InjectTLIMappings.h"
 #include "llvm/Transforms/Utils/LCSSA.h"
 #include "llvm/Transforms/Utils/LibCallsShrinkWrap.h"
 #include "llvm/Transforms/Utils/LoopSimplify.h"
+#include "llvm/Transforms/Utils/LoopVersioning.h"
 #include "llvm/Transforms/Utils/LowerInvoke.h"
 #include "llvm/Transforms/Utils/Mem2Reg.h"
 #include "llvm/Transforms/Utils/NameAnonGlobals.h"
 #include "llvm/Transforms/Utils/SymbolRewriter.h"
 #include "llvm/Transforms/Vectorize/LoadStoreVectorizer.h"
 #include "llvm/Transforms/Vectorize/LoopVectorize.h"
 #include "llvm/Transforms/Vectorize/SLPVectorizer.h"
 #include "llvm/Transforms/Vectorize/VectorCombine.h"

llvm/lib/Passes/PassRegistry.def

 FUNCTION_PASS("newgvn", NewGVNPass())
 FUNCTION_PASS("jump-threading", JumpThreadingPass())
 FUNCTION_PASS("partially-inline-libcalls", PartiallyInlineLibCallsPass())
 FUNCTION_PASS("lcssa", LCSSAPass())
 FUNCTION_PASS("loop-data-prefetch", LoopDataPrefetchPass())
 FUNCTION_PASS("loop-load-elim", LoopLoadEliminationPass())
 FUNCTION_PASS("loop-fusion", LoopFusePass())
 FUNCTION_PASS("loop-distribute", LoopDistributePass())
+FUNCTION_PASS("loop-versioning", LoopVersioningPass())
 FUNCTION_PASS("pgo-memop-opt", PGOMemOPSizeOpt())
 FUNCTION_PASS("print", PrintFunctionPass(dbgs()))
 FUNCTION_PASS("print<assumptions>", AssumptionPrinterPass(dbgs()))
 FUNCTION_PASS("print<block-freq>", BlockFrequencyPrinterPass(dbgs()))
 FUNCTION_PASS("print<branch-prob>", BranchProbabilityPrinterPass(dbgs()))
 FUNCTION_PASS("print<da>", DependenceAnalysisPrinterPass(dbgs()))
 FUNCTION_PASS("print<domtree>", DominatorTreePrinterPass(dbgs()))
 FUNCTION_PASS("print<postdomtree>", PostDominatorTreePrinterPass(dbgs()))

llvm/lib/Transforms/Scalar/Scalar.cpp

void llvm::initializeScalarOpts(PassRegistry &Registry) {
   initializeSpeculativeExecutionLegacyPassPass(Registry);
   initializeStraightLineStrengthReducePass(Registry);
   initializePlaceBackedgeSafepointsImplPass(Registry);
   initializePlaceSafepointsPass(Registry);
   initializeFloat2IntLegacyPassPass(Registry);
   initializeLoopDistributeLegacyPass(Registry);
   initializeLoopLoadEliminationPass(Registry);
   initializeLoopSimplifyCFGLegacyPassPass(Registry);
-  initializeLoopVersioningPassPass(Registry);
+  initializeLoopVersioningLegacyPassPass(Registry);
   initializeEntryExitInstrumenterPass(Registry);
   initializePostInlineEntryExitInstrumenterPass(Registry);
 }
 
 void LLVMAddLoopSimplifyCFGPass(LLVMPassManagerRef PM) {
   unwrap(PM)->add(createLoopSimplifyCFGPass());
 }
 

llvm/lib/Transforms/Utils/LoopVersioning.cpp

 // emits checks to prove this.
 //
 //===----------------------------------------------------------------------===//
 
 #include "llvm/Transforms/Utils/LoopVersioning.h"
 #include "llvm/ADT/ArrayRef.h"
 #include "llvm/Analysis/LoopAccessAnalysis.h"
 #include "llvm/Analysis/LoopInfo.h"
+#include "llvm/Analysis/ScalarEvolution.h"
 #include "llvm/IR/Dominators.h"
 #include "llvm/IR/MDBuilder.h"
+#include "llvm/IR/PassManager.h"
 #include "llvm/InitializePasses.h"
 #include "llvm/Support/CommandLine.h"
+#include "llvm/Transforms/Scalar/LoopPassManager.h"
 #include "llvm/Transforms/Utils/BasicBlockUtils.h"
 #include "llvm/Transforms/Utils/Cloning.h"
 #include "llvm/Transforms/Utils/ScalarEvolutionExpander.h"
 
 using namespace llvm;
 
 static cl::opt<bool>
     AnnotateNoAlias("loop-version-annotate-no-alias", cl::init(true),
if (NonAliasingScopeList != GroupToNonAliasingScopeList.end())
           LLVMContext::MD_noalias,
           MDNode::concatenate(
               VersionedInst->getMetadata(LLVMContext::MD_noalias),
               NonAliasingScopeList->second));
   }
 }
 
 namespace {
-/// Also expose this is a pass.  Currently this is only used for
-/// unit-testing.  It adds all memchecks necessary to remove all may-aliasing
-/// array accesses from the loop.
-class LoopVersioningPass : public FunctionPass {
-public:
-  LoopVersioningPass() : FunctionPass(ID) {
-    initializeLoopVersioningPassPass(*PassRegistry::getPassRegistry());
-  }
-
-  bool runOnFunction(Function &F) override {
-    auto *LI = &getAnalysis<LoopInfoWrapperPass>().getLoopInfo();
-    auto *LAA = &getAnalysis<LoopAccessLegacyAnalysis>();
-    auto *DT = &getAnalysis<DominatorTreeWrapperPass>().getDomTree();
-    auto *SE = &getAnalysis<ScalarEvolutionWrapperPass>().getSE();
-
-    // Build up a worklist of inner-loops to version. This is necessary as the
-    // act of versioning a loop creates new loops and can invalidate iterators
-    // across the loops.
-    SmallVector<Loop *, 8> Worklist;
+bool runImpl(LoopInfo *LI, std::function<const LoopAccessInfo &(Loop &)> GetLAA,
+             DominatorTree *DT, ScalarEvolution *SE) {
 
-    for (Loop *TopLevelLoop : *LI)
-      for (Loop *L : depth_first(TopLevelLoop))
-        // We only handle inner-most loops.
-        if (L->empty())
-          Worklist.push_back(L);
 
-    // Now walk the identified inner loops.
-    bool Changed = false;
-    for (Loop *L : Worklist) {
-      const LoopAccessInfo &LAI = LAA->getInfo(L);
-      if (L->isLoopSimplifyForm() && !LAI.hasConvergentOp() &&
-          (LAI.getNumRuntimePointerChecks() ||
-           !LAI.getPSE().getUnionPredicate().isAlwaysTrue())) {
-        LoopVersioning LVer(LAI, L, LI, DT, SE);
-        LVer.versionLoop();
-        LVer.annotateLoopWithNoAlias();
-        Changed = true;
-      }
-    }
+    // const LoopAccessInfo &LAI = LAA->getInfo(L);
+    const LoopAccessInfo &LAI = GetLAA(*L);
 
-    return Changed;
-  }
 
+/// Also expose this is a pass.  Currently this is only used for
+/// unit-testing.  It adds all memchecks necessary to remove all may-aliasing
+/// array accesses from the loop.
+class LoopVersioningLegacyPass : public FunctionPass {
+public:
+  LoopVersioningLegacyPass() : FunctionPass(ID) {
+    initializeLoopVersioningLegacyPassPass(*PassRegistry::getPassRegistry());
+  }
+
+  bool runOnFunction(Function &F) override {
+    auto *LI = &getAnalysis<LoopInfoWrapperPass>().getLoopInfo();
+    std::function<const LoopAccessInfo &(Loop &)> GetLAA =
+        [&](Loop &L) -> const LoopAccessInfo & {
+      return getAnalysis<LoopAccessLegacyAnalysis>().getInfo(&L);
+    };
+
+    auto *DT = &getAnalysis<DominatorTreeWrapperPass>().getDomTree();
+    auto *SE = &getAnalysis<ScalarEvolutionWrapperPass>().getSE();
+
+    return runImpl(LI, GetLAA, DT, SE);
+  }
+
   void getAnalysisUsage(AnalysisUsage &AU) const override {
     AU.addRequired<LoopInfoWrapperPass>();
     AU.addPreserved<LoopInfoWrapperPass>();
     AU.addRequired<LoopAccessLegacyAnalysis>();
     AU.addRequired<DominatorTreeWrapperPass>();
     AU.addPreserved<DominatorTreeWrapperPass>();
     AU.addRequired<ScalarEvolutionWrapperPass>();
   }
 
   static char ID;
 };
 }
 
 #define LVER_OPTION "loop-versioning"
 #define DEBUG_TYPE LVER_OPTION
 
-char LoopVersioningPass::ID;
+char LoopVersioningLegacyPass::ID;
 static const char LVer_name[] = "Loop Versioning";
 
-INITIALIZE_PASS_BEGIN(LoopVersioningPass, LVER_OPTION, LVer_name, false, false)
+INITIALIZE_PASS_BEGIN(LoopVersioningLegacyPass, LVER_OPTION, LVer_name, false,
+                      false)
 INITIALIZE_PASS_DEPENDENCY(LoopInfoWrapperPass)
 INITIALIZE_PASS_DEPENDENCY(LoopAccessLegacyAnalysis)
 INITIALIZE_PASS_DEPENDENCY(DominatorTreeWrapperPass)
 INITIALIZE_PASS_DEPENDENCY(ScalarEvolutionWrapperPass)
-INITIALIZE_PASS_END(LoopVersioningPass, LVER_OPTION, LVer_name, false, false)
+INITIALIZE_PASS_END(LoopVersioningLegacyPass, LVER_OPTION, LVer_name, false,
+                    false)
 
 namespace llvm {
-FunctionPass *createLoopVersioningPass() {
-  return new LoopVersioningPass();
+FunctionPass *createLoopVersioningLegacyPass() {
+  return new LoopVersioningLegacyPass();
+}
+
+PreservedAnalyses LoopVersioningPass::run(Function &F,
+                                          FunctionAnalysisManager &AM) {
+  auto &SE = AM.getResult<ScalarEvolutionAnalysis>(F);
+  auto &LI = AM.getResult<LoopAnalysis>(F);
+  auto &TTI = AM.getResult<TargetIRAnalysis>(F);
+  auto &DT = AM.getResult<DominatorTreeAnalysis>(F);
+  auto &TLI = AM.getResult<TargetLibraryAnalysis>(F);
+  auto &AA = AM.getResult<AAManager>(F);
+  auto &AC = AM.getResult<AssumptionAnalysis>(F);
+  MemorySSA *MSSA = EnableMSSALoopDependency
+                        ? &AM.getResult<MemorySSAAnalysis>(F).getMSSA()
+                        : nullptr;
+
+  auto &LAM = AM.getResult<LoopAnalysisManagerFunctionProxy>(F).getManager();
+  std::function<const LoopAccessInfo &(Loop &)> GetLAA =
+      [&](Loop &L) -> const LoopAccessInfo & {
+    LoopStandardAnalysisResults AR = {AA, AC, DT, LI, SE, TLI, TTI, MSSA};
+    return LAM.getResult<LoopAccessAnalysis>(L, AR);
+  };
+
+  if (runImpl(&LI, GetLAA, &DT, &SE)) {
+    return PreservedAnalyses::none();
+  }
+  return PreservedAnalyses::all();
 }
 }