1 files changed, 618 insertions, 0 deletions
diff --git a/llvm/lib/Transforms/Utils/AssumeBundleBuilder.cpp b/llvm/lib/Transforms/Utils/AssumeBundleBuilder.cpp
new file mode 100644
index 000000000000..7ff73fcdada7
--- /dev/null
+++ b/llvm/lib/Transforms/Utils/AssumeBundleBuilder.cpp
@@ -0,0 +1,618 @@
+//===- AssumeBundleBuilder.cpp - tools to preserve informations -*- C++ -*-===//
+//
+// Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions.
+// See https://llvm.org/LICENSE.txt for license information.
+// SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception
+//
+//===----------------------------------------------------------------------===//
+
+#define DEBUG_TYPE "assume-builder"
+
+#include "llvm/Transforms/Utils/AssumeBundleBuilder.h"
+#include "llvm/ADT/DepthFirstIterator.h"
+#include "llvm/ADT/MapVector.h"
+#include "llvm/ADT/Statistic.h"
+#include "llvm/Analysis/AssumeBundleQueries.h"
+#include "llvm/Analysis/AssumptionCache.h"
+#include "llvm/Analysis/ValueTracking.h"
+#include "llvm/IR/Dominators.h"
+#include "llvm/IR/Function.h"
+#include "llvm/IR/InstIterator.h"
+#include "llvm/IR/IntrinsicInst.h"
+#include "llvm/IR/Module.h"
+#include "llvm/InitializePasses.h"
+#include "llvm/Support/CommandLine.h"
+#include "llvm/Support/DebugCounter.h"
+#include "llvm/Transforms/Utils/Local.h"
+
+using namespace llvm;
+
+cl::opt<bool> ShouldPreserveAllAttributes(
+    "assume-preserve-all", cl::init(false), cl::Hidden,
+    cl::desc("enable preservation of all attrbitues. even those that are "
+             "unlikely to be usefull"));
+
+cl::opt<bool> EnableKnowledgeRetention(
+    "enable-knowledge-retention", cl::init(false), cl::Hidden,
+    cl::desc(
+        "enable preservation of attributes throughout code transformation"));
+
+STATISTIC(NumAssumeBuilt, "Number of assume built by the assume builder");
+STATISTIC(NumBundlesInAssumes, "Total number of Bundles in the assume built");
+STATISTIC(NumAssumesMerged,
+          "Number of assume merged by the assume simplify pass");
+STATISTIC(NumAssumesRemoved,
+          "Number of assume removed by the assume simplify pass");
+
+DEBUG_COUNTER(BuildAssumeCounter, "assume-builder-counter",
+              "Controls which assumes gets created");
+
+namespace {
+
+bool isUsefullToPreserve(Attribute::AttrKind Kind) {
+  switch (Kind) {
+    case Attribute::NonNull:
+    case Attribute::Alignment:
+    case Attribute::Dereferenceable:
+    case Attribute::DereferenceableOrNull:
+    case Attribute::Cold:
+      return true;
+    default:
+      return false;
+  }
+}
+
+/// This function will try to transform the given knowledge into a more
+/// canonical one. the canonical knowledge maybe the given one.
+RetainedKnowledge canonicalizedKnowledge(RetainedKnowledge RK, Module *M) {
+  switch (RK.AttrKind) {
+  default:
+    return RK;
+  case Attribute::NonNull:
+    RK.WasOn = GetUnderlyingObject(RK.WasOn, M->getDataLayout());
+    return RK;
+  case Attribute::Alignment: {
+    Value *V = RK.WasOn->stripInBoundsOffsets([&](const Value *Strip) {
+      if (auto *GEP = dyn_cast<GEPOperator>(Strip))
+        RK.ArgValue =
+            MinAlign(RK.ArgValue,
+                     GEP->getMaxPreservedAlignment(M->getDataLayout()).value());
+    });
+    RK.WasOn = V;
+    return RK;
+  }
+  case Attribute::Dereferenceable:
+  case Attribute::DereferenceableOrNull: {
+    int64_t Offset = 0;
+    Value *V = GetPointerBaseWithConstantOffset(
+        RK.WasOn, Offset, M->getDataLayout(), /*AllowNonInBounds*/ false);
+    if (Offset < 0)
+      return RK;
+    RK.ArgValue = RK.ArgValue + Offset;
+    RK.WasOn = V;
+  }
+  }
+  return RK;
+}
+
+/// This class contain all knowledge that have been gather while building an
+/// llvm.assume and the function to manipulate it.
+struct AssumeBuilderState {
+  Module *M;
+
+  using MapKey = std::pair<Value *, Attribute::AttrKind>;
+  SmallMapVector<MapKey, unsigned, 8> AssumedKnowledgeMap;
+  Instruction *InstBeingRemoved = nullptr;
+  AssumptionCache* AC = nullptr;
+  DominatorTree* DT = nullptr;
+
+  AssumeBuilderState(Module *M, Instruction *I = nullptr,
+                     AssumptionCache *AC = nullptr, DominatorTree *DT = nullptr)
+      : M(M), InstBeingRemoved(I), AC(AC), DT(DT) {}
+
+  bool tryToPreserveWithoutAddingAssume(RetainedKnowledge RK) {
+    if (!InstBeingRemoved || !RK.WasOn)
+      return false;
+    bool HasBeenPreserved = false;
+    Use* ToUpdate = nullptr;
+    getKnowledgeForValue(
+        RK.WasOn, {RK.AttrKind}, AC,
+        [&](RetainedKnowledge RKOther, Instruction *Assume,
+            const CallInst::BundleOpInfo *Bundle) {
+          if (!isValidAssumeForContext(Assume, InstBeingRemoved, DT))
+            return false;
+          if (RKOther.ArgValue >= RK.ArgValue) {
+            HasBeenPreserved = true;
+            return true;
+          } else if (isValidAssumeForContext(InstBeingRemoved, Assume,
+                                             DT)) {
+            HasBeenPreserved = true;
+            IntrinsicInst *Intr = cast<IntrinsicInst>(Assume);
+            ToUpdate = &Intr->op_begin()[Bundle->Begin + ABA_Argument];
+            return true;
+          }
+          return false;
+        });
+    if (ToUpdate)
+      ToUpdate->set(
+          ConstantInt::get(Type::getInt64Ty(M->getContext()), RK.ArgValue));
+    return HasBeenPreserved;
+  }
+
+  bool isKnowledgeWorthPreserving(RetainedKnowledge RK) {
+    if (!RK)
+      return false;
+    if (!RK.WasOn)
+      return true;
+    if (RK.WasOn->getType()->isPointerTy()) {
+      Value *UnderlyingPtr = GetUnderlyingObject(RK.WasOn, M->getDataLayout());
+      if (isa<AllocaInst>(UnderlyingPtr) || isa<GlobalValue>(UnderlyingPtr))
+        return false;
+    }
+    if (auto *Arg = dyn_cast<Argument>(RK.WasOn)) {
+      if (Arg->hasAttribute(RK.AttrKind) &&
+          (!Attribute::doesAttrKindHaveArgument(RK.AttrKind) ||
+           Arg->getAttribute(RK.AttrKind).getValueAsInt() >= RK.ArgValue))
+        return false;
+      return true;
+    }
+    if (auto *Inst = dyn_cast<Instruction>(RK.WasOn))
+      if (wouldInstructionBeTriviallyDead(Inst)) {
+        if (RK.WasOn->use_empty())
+          return false;
+        Use *SingleUse = RK.WasOn->getSingleUndroppableUse();
+        if (SingleUse && SingleUse->getUser() == InstBeingRemoved)
+          return false;
+      }
+    return true;
+  }
+
+  void addKnowledge(RetainedKnowledge RK) {
+    RK = canonicalizedKnowledge(RK, M);
+
+    if (!isKnowledgeWorthPreserving(RK))
+      return;
+
+    if (tryToPreserveWithoutAddingAssume(RK))
+      return;
+    MapKey Key{RK.WasOn, RK.AttrKind};
+    auto Lookup = AssumedKnowledgeMap.find(Key);
+    if (Lookup == AssumedKnowledgeMap.end()) {
+      AssumedKnowledgeMap[Key] = RK.ArgValue;
+      return;
+    }
+    assert(((Lookup->second == 0 && RK.ArgValue == 0) ||
+            (Lookup->second != 0 && RK.ArgValue != 0)) &&
+           "inconsistent argument value");
+
+    /// This is only desirable because for all attributes taking an argument
+    /// higher is better.
+    Lookup->second = std::max(Lookup->second, RK.ArgValue);
+  }
+
+  void addAttribute(Attribute Attr, Value *WasOn) {
+    if (Attr.isTypeAttribute() || Attr.isStringAttribute() ||
+        (!ShouldPreserveAllAttributes &&
+         !isUsefullToPreserve(Attr.getKindAsEnum())))
+      return;
+    unsigned AttrArg = 0;
+    if (Attr.isIntAttribute())
+      AttrArg = Attr.getValueAsInt();
+    addKnowledge({Attr.getKindAsEnum(), AttrArg, WasOn});
+  }
+
+  void addCall(const CallBase *Call) {
+    auto addAttrList = [&](AttributeList AttrList) {
+      for (unsigned Idx = AttributeList::FirstArgIndex;
+           Idx < AttrList.getNumAttrSets(); Idx++)
+        for (Attribute Attr : AttrList.getAttributes(Idx))
+          addAttribute(Attr, Call->getArgOperand(Idx - 1));
+      for (Attribute Attr : AttrList.getFnAttributes())
+        addAttribute(Attr, nullptr);
+    };
+    addAttrList(Call->getAttributes());
+    if (Function *Fn = Call->getCalledFunction())
+      addAttrList(Fn->getAttributes());
+  }
+
+  IntrinsicInst *build() {
+    if (AssumedKnowledgeMap.empty())
+      return nullptr;
+    if (!DebugCounter::shouldExecute(BuildAssumeCounter))
+      return nullptr;
+    Function *FnAssume = Intrinsic::getDeclaration(M, Intrinsic::assume);
+    LLVMContext &C = M->getContext();
+    SmallVector<OperandBundleDef, 8> OpBundle;
+    for (auto &MapElem : AssumedKnowledgeMap) {
+      SmallVector<Value *, 2> Args;
+      if (MapElem.first.first)
+        Args.push_back(MapElem.first.first);
+
+      /// This is only valid because for all attribute that currently exist a
+      /// value of 0 is useless. and should not be preserved.
+      if (MapElem.second)
+        Args.push_back(ConstantInt::get(Type::getInt64Ty(M->getContext()),
+                                        MapElem.second));
+      OpBundle.push_back(OperandBundleDefT<Value *>(
+          std::string(Attribute::getNameFromAttrKind(MapElem.first.second)),
+          Args));
+      NumBundlesInAssumes++;
+    }
+    NumAssumeBuilt++;
+    return cast<IntrinsicInst>(CallInst::Create(
+        FnAssume, ArrayRef<Value *>({ConstantInt::getTrue(C)}), OpBundle));
+  }
+
+  void addAccessedPtr(Instruction *MemInst, Value *Pointer, Type *AccType,
+                      MaybeAlign MA) {
+    unsigned DerefSize = MemInst->getModule()
+                             ->getDataLayout()
+                             .getTypeStoreSize(AccType)
+                             .getKnownMinSize();
+    if (DerefSize != 0) {
+      addKnowledge({Attribute::Dereferenceable, DerefSize, Pointer});
+      if (!NullPointerIsDefined(MemInst->getFunction(),
+                                Pointer->getType()->getPointerAddressSpace()))
+        addKnowledge({Attribute::NonNull, 0u, Pointer});
+    }
+    if (MA.valueOrOne() > 1)
+      addKnowledge(
+          {Attribute::Alignment, unsigned(MA.valueOrOne().value()), Pointer});
+  }
+
+  void addInstruction(Instruction *I) {
+    if (auto *Call = dyn_cast<CallBase>(I))
+      return addCall(Call);
+    if (auto *Load = dyn_cast<LoadInst>(I))
+      return addAccessedPtr(I, Load->getPointerOperand(), Load->getType(),
+                            Load->getAlign());
+    if (auto *Store = dyn_cast<StoreInst>(I))
+      return addAccessedPtr(I, Store->getPointerOperand(),
+                            Store->getValueOperand()->getType(),
+                            Store->getAlign());
+    // TODO: Add support for the other Instructions.
+    // TODO: Maybe we should look around and merge with other llvm.assume.
+  }
+};
+
+} // namespace
+
+IntrinsicInst *llvm::buildAssumeFromInst(Instruction *I) {
+  if (!EnableKnowledgeRetention)
+    return nullptr;
+  AssumeBuilderState Builder(I->getModule());
+  Builder.addInstruction(I);
+  return Builder.build();
+}
+
+void llvm::salvageKnowledge(Instruction *I, AssumptionCache *AC,
+                            DominatorTree *DT) {
+  if (!EnableKnowledgeRetention || I->isTerminator())
+    return;
+  AssumeBuilderState Builder(I->getModule(), I, AC, DT);
+  Builder.addInstruction(I);
+  if (IntrinsicInst *Intr = Builder.build()) {
+    Intr->insertBefore(I);
+    if (AC)
+      AC->registerAssumption(Intr);
+  }
+}
+
+namespace {
+
+struct AssumeSimplify {
+  Function &F;
+  AssumptionCache &AC;
+  DominatorTree *DT;
+  LLVMContext &C;
+  SmallDenseSet<IntrinsicInst *> CleanupToDo;
+  StringMapEntry<uint32_t> *IgnoreTag;
+  SmallDenseMap<BasicBlock *, SmallVector<IntrinsicInst *, 4>, 8> BBToAssume;
+  bool MadeChange = false;
+
+  AssumeSimplify(Function &F, AssumptionCache &AC, DominatorTree *DT,
+                 LLVMContext &C)
+      : F(F), AC(AC), DT(DT), C(C),
+        IgnoreTag(C.getOrInsertBundleTag(IgnoreBundleTag)) {}
+
+  void buildMapping(bool FilterBooleanArgument) {
+    BBToAssume.clear();
+    for (Value *V : AC.assumptions()) {
+      if (!V)
+        continue;
+      IntrinsicInst *Assume = cast<IntrinsicInst>(V);
+      if (FilterBooleanArgument) {
+        auto *Arg = dyn_cast<ConstantInt>(Assume->getOperand(0));
+        if (!Arg || Arg->isZero())
+          continue;
+      }
+      BBToAssume[Assume->getParent()].push_back(Assume);
+    }
+
+    for (auto &Elem : BBToAssume) {
+      llvm::sort(Elem.second,
+                 [](const IntrinsicInst *LHS, const IntrinsicInst *RHS) {
+                   return LHS->comesBefore(RHS);
+                 });
+    }
+  }
+
+  /// Remove all asumes in CleanupToDo if there boolean argument is true and
+  /// ForceCleanup is set or the assume doesn't hold valuable knowledge.
+  void RunCleanup(bool ForceCleanup) {
+    for (IntrinsicInst *Assume : CleanupToDo) {
+      auto *Arg = dyn_cast<ConstantInt>(Assume->getOperand(0));
+      if (!Arg || Arg->isZero() ||
+          (!ForceCleanup && !isAssumeWithEmptyBundle(*Assume)))
+        continue;
+      MadeChange = true;
+      if (ForceCleanup)
+        NumAssumesMerged++;
+      else
+        NumAssumesRemoved++;
+      Assume->eraseFromParent();
+    }
+    CleanupToDo.clear();
+  }
+
+  /// Remove knowledge stored in assume when it is already know by an attribute
+  /// or an other assume. This can when valid update an existing knowledge in an
+  /// attribute or an other assume.
+  void dropRedundantKnowledge() {
+    struct MapValue {
+      IntrinsicInst *Assume;
+      unsigned ArgValue;
+      CallInst::BundleOpInfo *BOI;
+    };
+    buildMapping(false);
+    SmallDenseMap<std::pair<Value *, Attribute::AttrKind>,
+                  SmallVector<MapValue, 2>, 16>
+        Knowledge;
+    for (BasicBlock *BB : depth_first(&F))
+      for (Value *V : BBToAssume[BB]) {
+        if (!V)
+          continue;
+        IntrinsicInst *Assume = cast<IntrinsicInst>(V);
+        for (CallInst::BundleOpInfo &BOI : Assume->bundle_op_infos()) {
+          auto RemoveFromAssume = [&]() {
+            CleanupToDo.insert(Assume);
+            if (BOI.Begin != BOI.End) {
+              Use *U = &Assume->op_begin()[BOI.Begin + ABA_WasOn];
+              U->set(UndefValue::get(U->get()->getType()));
+            }
+            BOI.Tag = IgnoreTag;
+          };
+          if (BOI.Tag == IgnoreTag) {
+            CleanupToDo.insert(Assume);
+            continue;
+          }
+          RetainedKnowledge RK = getKnowledgeFromBundle(*Assume, BOI);
+          if (auto *Arg = dyn_cast_or_null<Argument>(RK.WasOn)) {
+            bool HasSameKindAttr = Arg->hasAttribute(RK.AttrKind);
+            if (HasSameKindAttr)
+              if (!Attribute::doesAttrKindHaveArgument(RK.AttrKind) ||
+                  Arg->getAttribute(RK.AttrKind).getValueAsInt() >=
+                      RK.ArgValue) {
+                RemoveFromAssume();
+                continue;
+              }
+            if (isValidAssumeForContext(
+                    Assume, &*F.getEntryBlock().getFirstInsertionPt()) ||
+                Assume == &*F.getEntryBlock().getFirstInsertionPt()) {
+              if (HasSameKindAttr)
+                Arg->removeAttr(RK.AttrKind);
+              Arg->addAttr(Attribute::get(C, RK.AttrKind, RK.ArgValue));
+              MadeChange = true;
+              RemoveFromAssume();
+              continue;
+            }
+          }
+          auto &Lookup = Knowledge[{RK.WasOn, RK.AttrKind}];
+          for (MapValue &Elem : Lookup) {
+            if (!isValidAssumeForContext(Elem.Assume, Assume, DT))
+              continue;
+            if (Elem.ArgValue >= RK.ArgValue) {
+              RemoveFromAssume();
+              continue;
+            } else if (isValidAssumeForContext(Assume, Elem.Assume, DT)) {
+              Elem.Assume->op_begin()[Elem.BOI->Begin + ABA_Argument].set(
+                  ConstantInt::get(Type::getInt64Ty(C), RK.ArgValue));
+              MadeChange = true;
+              RemoveFromAssume();
+              continue;
+            }
+          }
+          Lookup.push_back({Assume, RK.ArgValue, &BOI});
+        }
+      }
+  }
+
+  using MergeIterator = SmallVectorImpl<IntrinsicInst *>::iterator;
+
+  /// Merge all Assumes from Begin to End in and insert the resulting assume as
+  /// high as possible in the basicblock.
+  void mergeRange(BasicBlock *BB, MergeIterator Begin, MergeIterator End) {
+    if (Begin == End || std::next(Begin) == End)
+      return;
+    /// Provide no additional information so that AssumeBuilderState doesn't
+    /// try to do any punning since it already has been done better.
+    AssumeBuilderState Builder(F.getParent());
+
+    /// For now it is initialized to the best value it could have
+    Instruction *InsertPt = BB->getFirstNonPHI();
+    if (isa<LandingPadInst>(InsertPt))
+      InsertPt = InsertPt->getNextNode();
+    for (IntrinsicInst *I : make_range(Begin, End)) {
+      CleanupToDo.insert(I);
+      for (CallInst::BundleOpInfo &BOI : I->bundle_op_infos()) {
+        RetainedKnowledge RK = getKnowledgeFromBundle(*I, BOI);
+        if (!RK)
+          continue;
+        Builder.addKnowledge(RK);
+        if (auto *I = dyn_cast_or_null<Instruction>(RK.WasOn))
+          if (I->getParent() == InsertPt->getParent() &&
+              (InsertPt->comesBefore(I) || InsertPt == I))
+            InsertPt = I->getNextNode();
+      }
+    }
+
+    /// Adjust InsertPt if it is before Begin, since mergeAssumes only
+    /// guarantees we can place the resulting assume between Begin and End.
+    if (InsertPt->comesBefore(*Begin))
+      for (auto It = (*Begin)->getIterator(), E = InsertPt->getIterator();
+           It != E; --It)
+        if (!isGuaranteedToTransferExecutionToSuccessor(&*It)) {
+          InsertPt = It->getNextNode();
+          break;
+        }
+    IntrinsicInst *MergedAssume = Builder.build();
+    if (!MergedAssume)
+      return;
+    MadeChange = true;
+    MergedAssume->insertBefore(InsertPt);
+    AC.registerAssumption(MergedAssume);
+  }
+
+  /// Merge assume when they are in the same BasicBlock and for all instruction
+  /// between them isGuaranteedToTransferExecutionToSuccessor returns true.
+  void mergeAssumes() {
+    buildMapping(true);
+
+    SmallVector<MergeIterator, 4> SplitPoints;
+    for (auto &Elem : BBToAssume) {
+      SmallVectorImpl<IntrinsicInst *> &AssumesInBB = Elem.second;
+      if (AssumesInBB.size() < 2)
+        continue;
+      /// AssumesInBB is already sorted by order in the block.
+
+      BasicBlock::iterator It = AssumesInBB.front()->getIterator();
+      BasicBlock::iterator E = AssumesInBB.back()->getIterator();
+      SplitPoints.push_back(AssumesInBB.begin());
+      MergeIterator LastSplit = AssumesInBB.begin();
+      for (; It != E; ++It)
+        if (!isGuaranteedToTransferExecutionToSuccessor(&*It)) {
+          for (; (*LastSplit)->comesBefore(&*It); ++LastSplit)
+            ;
+          if (SplitPoints.back() != LastSplit)
+            SplitPoints.push_back(LastSplit);
+        }
+      SplitPoints.push_back(AssumesInBB.end());
+      for (auto SplitIt = SplitPoints.begin();
+           SplitIt != std::prev(SplitPoints.end()); SplitIt++) {
+        mergeRange(Elem.first, *SplitIt, *(SplitIt + 1));
+      }
+      SplitPoints.clear();
+    }
+  }
+};
+
+bool simplifyAssumes(Function &F, AssumptionCache *AC, DominatorTree *DT) {
+  AssumeSimplify AS(F, *AC, DT, F.getContext());
+
+  /// Remove knowledge that is already known by a dominating other assume or an
+  /// attribute.
+  AS.dropRedundantKnowledge();
+
+  /// Remove assume that are empty.
+  AS.RunCleanup(false);
+
+  /// Merge assume in the same basicblock when possible.
+  AS.mergeAssumes();
+
+  /// Remove assume that were merged.
+  AS.RunCleanup(true);
+  return AS.MadeChange;
+}
+
+} // namespace
+
+PreservedAnalyses AssumeSimplifyPass::run(Function &F,
+                                          FunctionAnalysisManager &AM) {
+  if (!EnableKnowledgeRetention)
+    return PreservedAnalyses::all();
+  simplifyAssumes(F, &AM.getResult<AssumptionAnalysis>(F),
+                  AM.getCachedResult<DominatorTreeAnalysis>(F));
+  return PreservedAnalyses::all();
+}
+
+namespace {
+class AssumeSimplifyPassLegacyPass : public FunctionPass {
+public:
+  static char ID;
+
+  AssumeSimplifyPassLegacyPass() : FunctionPass(ID) {
+    initializeAssumeSimplifyPassLegacyPassPass(
+        *PassRegistry::getPassRegistry());
+  }
+  bool runOnFunction(Function &F) override {
+    if (skipFunction(F) || !EnableKnowledgeRetention)
+      return false;
+    AssumptionCache &AC =
+        getAnalysis<AssumptionCacheTracker>().getAssumptionCache(F);
+    DominatorTreeWrapperPass *DTWP =
+        getAnalysisIfAvailable<DominatorTreeWrapperPass>();
+    return simplifyAssumes(F, &AC, DTWP ? &DTWP->getDomTree() : nullptr);
+  }
+
+  void getAnalysisUsage(AnalysisUsage &AU) const override {
+    AU.addRequired<AssumptionCacheTracker>();
+
+    AU.setPreservesAll();
+  }
+};
+} // namespace
+
+char AssumeSimplifyPassLegacyPass::ID = 0;
+
+INITIALIZE_PASS_BEGIN(AssumeSimplifyPassLegacyPass, "assume-simplify",
+                      "Assume Simplify", false, false)
+INITIALIZE_PASS_DEPENDENCY(AssumptionCacheTracker)
+INITIALIZE_PASS_END(AssumeSimplifyPassLegacyPass, "assume-simplify",
+                    "Assume Simplify", false, false)
+
+FunctionPass *llvm::createAssumeSimplifyPass() {
+  return new AssumeSimplifyPassLegacyPass();
+}
+
+PreservedAnalyses AssumeBuilderPass::run(Function &F,
+                                         FunctionAnalysisManager &AM) {
+  AssumptionCache *AC = &AM.getResult<AssumptionAnalysis>(F);
+  DominatorTree* DT = AM.getCachedResult<DominatorTreeAnalysis>(F);
+  for (Instruction &I : instructions(F))
+    salvageKnowledge(&I, AC, DT);
+  return PreservedAnalyses::all();
+}
+
+namespace {
+class AssumeBuilderPassLegacyPass : public FunctionPass {
+public:
+  static char ID;
+
+  AssumeBuilderPassLegacyPass() : FunctionPass(ID) {
+    initializeAssumeBuilderPassLegacyPassPass(*PassRegistry::getPassRegistry());
+  }
+  bool runOnFunction(Function &F) override {
+    AssumptionCache &AC =
+        getAnalysis<AssumptionCacheTracker>().getAssumptionCache(F);
+    DominatorTreeWrapperPass *DTWP =
+        getAnalysisIfAvailable<DominatorTreeWrapperPass>();
+    for (Instruction &I : instructions(F))
+      salvageKnowledge(&I, &AC, DTWP ? &DTWP->getDomTree() : nullptr);
+    return true;
+  }
+
+  void getAnalysisUsage(AnalysisUsage &AU) const override {
+    AU.addRequired<AssumptionCacheTracker>();
+
+    AU.setPreservesAll();
+  }
+};
+} // namespace
+
+char AssumeBuilderPassLegacyPass::ID = 0;
+
+INITIALIZE_PASS_BEGIN(AssumeBuilderPassLegacyPass, "assume-builder",
+                      "Assume Builder", false, false)
+INITIALIZE_PASS_DEPENDENCY(AssumptionCacheTracker)
+INITIALIZE_PASS_END(AssumeBuilderPassLegacyPass, "assume-builder",
+                    "Assume Builder", false, false)