Add an Assumption-Tracking Pass

This adds an immutable pass, AssumptionTracker, which keeps a cache of
@llvm.assume call instructions within a module. It uses callback value handles
to keep stale functions and intrinsics out of the map, and it relies on any
code that creates new @llvm.assume calls to notify it of the new instructions.
The benefit is that code needing to find @llvm.assume intrinsics can do so
directly, without scanning the function, thus allowing the cost of @llvm.assume
handling to be negligible when none are present.

The current design is intended to be lightweight. We don't keep track of
anything until we need a list of assumptions in some function. The first time
this happens, we scan the function. After that, we add/remove @llvm.assume
calls from the cache in response to registration calls and ValueHandle
callbacks.

There are no new direct test cases for this pass, but because it calls it
validation function upon module finalization, we'll pick up detectable
inconsistencies from the other tests that touch @llvm.assume calls.

This pass will be used by follow-up commits that make use of @llvm.assume.

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@217334 91177308-0d34-0410-b5e6-96231b3b80d8

include/llvm/Analysis/AssumptionTracker.h

@@ -0,0 +1,128 @@
+//===- llvm/Analysis/AssumptionTracker.h - Track @llvm.assume ---*- C++ -*-===//
+//
+//                     The LLVM Compiler Infrastructure
+//
+// This file is distributed under the University of Illinois Open Source
+// License. See LICENSE.TXT for details.
+//
+//===----------------------------------------------------------------------===//
+//
+// This file contains a pass that keeps track of @llvm.assume intrinsics in
+// the functions of a module (allowing assumptions within any function to be
+// found cheaply by other parts of the optimizer).
+//
+//===----------------------------------------------------------------------===//
+
+#ifndef LLVM_ANALYSIS_ASSUMPTIONTRACKER_H
+#define LLVM_ANALYSIS_ASSUMPTIONTRACKER_H
+
+#include "llvm/ADT/DenseMap.h"
+#include "llvm/ADT/DenseSet.h"
+#include "llvm/ADT/SmallSet.h"
+#include "llvm/IR/Function.h"
+#include "llvm/IR/Instructions.h"
+#include "llvm/IR/ValueHandle.h"
+#include "llvm/Pass.h"
+#include <memory>
+
+namespace llvm {
+
+/// An immutable pass that tracks @llvm.assume intrinsics in a module.
+class AssumptionTracker : public ImmutablePass {
+  /// A callback value handle applied to function objects, which we use to
+  /// delete our cache of intrinsics for a function when it is deleted.
+  class FunctionCallbackVH : public CallbackVH {
+    AssumptionTracker *AT;
+    void deleted() override;
+
+    public:
+      typedef DenseMapInfo<Value *> DMI;
+
+      FunctionCallbackVH(Value *V, AssumptionTracker *AT = nullptr)
+        : CallbackVH(V), AT(AT) {}
+  };
+
+  /// A callback value handle applied to call instructions, which keeps
+  /// track of the call's parent function so that we can remove a
+  /// assumption intrinsic call from our cache when the instruction is
+  /// deleted.
+  class CallCallbackVH : public CallbackVH {
+    AssumptionTracker *AT;
+    void deleted() override;
+
+    // We store the function here because we need it to lookup the set
+    // containing this handle when the underlying CallInst is being deleted.
+    Function *F;
+
+    public:
+      typedef DenseMapInfo<Instruction *> DMI;
+
+      CallCallbackVH(Instruction *I, AssumptionTracker *AT = nullptr)
+        : CallbackVH(I), AT(AT), F(nullptr) {
+        if (I != DMI::getEmptyKey() && I != DMI::getTombstoneKey())
+          F = I->getParent()->getParent();
+      }
+
+      operator CallInst*() const {
+        Value *V = getValPtr();
+        if (V == DMI::getEmptyKey() || V == DMI::getTombstoneKey())
+          return static_cast<CallInst*>(V);
+
+        return cast<CallInst>(V);
+      }
+
+      CallInst *operator->() const { return cast<CallInst>(getValPtr()); }
+      CallInst &operator*() const { return *cast<CallInst>(getValPtr()); }
+  };
+
+  friend FunctionCallbackVH;
+  friend CallCallbackVH;
+
+  // FIXME: SmallSet might be better here, but it currently has no iterators.
+  typedef DenseSet<CallCallbackVH, CallCallbackVH::DMI> CallHandleSet;
+  typedef DenseMap<FunctionCallbackVH, std::unique_ptr<CallHandleSet>,
+                   FunctionCallbackVH::DMI> FunctionCallsMap;
+  FunctionCallsMap CachedAssumeCalls;
+
+  /// Scan the provided function for @llvm.assume intrinsic calls. Returns an
+  /// iterator to the set for this function in the CachedAssumeCalls map.
+  FunctionCallsMap::iterator scanFunction(Function *F);
+
+public:
+  /// Remove the cache of @llvm.assume intrinsics for the given function.
+  void forgetCachedAssumptions(Function *F);
+
+  /// Add an @llvm.assume intrinsic to the cache for its parent function.
+  void registerAssumption(CallInst *CI);
+
+  typedef CallHandleSet::iterator assumption_iterator;
+  typedef iterator_range<assumption_iterator> assumption_range;
+
+  inline assumption_range assumptions(Function *F) {
+    FunctionCallsMap::iterator I = CachedAssumeCalls.find(F);
+    if (I == CachedAssumeCalls.end()) {
+      I = scanFunction(F);
+    }
+
+    return assumption_range(I->second->begin(), I->second->end());
+  }
+
+  AssumptionTracker();
+  ~AssumptionTracker();
+
+  void releaseMemory() override {
+    CachedAssumeCalls.shrink_and_clear();
+  }
+
+  void verifyAnalysis() const override;
+  bool doFinalization(Module &) override {
+    verifyAnalysis();
+    return false;
+  }
+
+  static char ID; // Pass identification, replacement for typeid
+};
+
+} // end namespace llvm
+
+#endif

include/llvm/InitializePasses.h

@@ -262,6 +262,7 @@ void initializeDataLayoutPassPass(PassRegistry &);
 void initializeTargetTransformInfoAnalysisGroup(PassRegistry&);
 void initializeNoTTIPass(PassRegistry&);
 void initializeTargetLibraryInfoPass(PassRegistry&);
+void initializeAssumptionTrackerPass(PassRegistry &);
 void initializeTwoAddressInstructionPassPass(PassRegistry&);
 void initializeTypeBasedAliasAnalysisPass(PassRegistry&);
 void initializeScopedNoAliasAAPass(PassRegistry&);

include/llvm/Transforms/Utils/Cloning.h

@@ -44,6 +44,7 @@ class Loop;
 class LoopInfo;
 class AllocaInst;
 class AliasAnalysis;
+class AssumptionTracker;
 
 /// CloneModule - Return an exact copy of the specified module
 ///
@@ -160,14 +161,16 @@ class InlineFunctionInfo {
 public:
   explicit InlineFunctionInfo(CallGraph *cg = nullptr,
                               const DataLayout *DL = nullptr,
-                              AliasAnalysis *AA = nullptr)
-    : CG(cg), DL(DL), AA(AA) {}
+                              AliasAnalysis *AA = nullptr,
+                              AssumptionTracker *AT = nullptr)
+    : CG(cg), DL(DL), AA(AA), AT(AT) {}
 
   /// CG - If non-null, InlineFunction will update the callgraph to reflect the
   /// changes it makes.
   CallGraph *CG;
   const DataLayout *DL;
   AliasAnalysis *AA;
+  AssumptionTracker *AT;
 
   /// StaticAllocas - InlineFunction fills this in with all static allocas that
   /// get copied into the caller.

include/llvm/Transforms/Utils/UnrollLoop.h

@@ -18,6 +18,7 @@
 
 namespace llvm {
 
+class AssumptionTracker;
 class Loop;
 class LoopInfo;
 class LPPassManager;
@@ -25,7 +26,7 @@ class Pass;
 
 bool UnrollLoop(Loop *L, unsigned Count, unsigned TripCount, bool AllowRuntime,
                 unsigned TripMultiple, LoopInfo *LI, Pass *PP,
-                LPPassManager *LPM);
+                LPPassManager *LPM, AssumptionTracker *AT);
 
 bool UnrollRuntimeLoopProlog(Loop *L, unsigned Count, LoopInfo *LI,
                              LPPassManager* LPM);

lib/Analysis/AssumptionTracker.cpp

@@ -0,0 +1,113 @@
+//===- AssumptionTracker.cpp - Track @llvm.assume -------------------------===//
+//
+//                     The LLVM Compiler Infrastructure
+//
+// This file is distributed under the University of Illinois Open Source
+// License. See LICENSE.TXT for details.
+//
+//===----------------------------------------------------------------------===//
+//
+// This file contains a pass that keeps track of @llvm.assume intrinsics in
+// the functions of a module.
+//
+//===----------------------------------------------------------------------===//
+
+#include "llvm/Analysis/AssumptionTracker.h"
+#include "llvm/IR/CallSite.h"
+#include "llvm/IR/Dominators.h"
+#include "llvm/IR/Function.h"
+#include "llvm/IR/Instructions.h"
+#include "llvm/IR/IntrinsicInst.h"
+#include "llvm/IR/PatternMatch.h"
+#include "llvm/Support/Debug.h"
+using namespace llvm;
+using namespace llvm::PatternMatch;
+
+void AssumptionTracker::FunctionCallbackVH::deleted() {
+  AT->forgetCachedAssumptions(cast<Function>(getValPtr()));
+  // 'this' now dangles!
+}
+
+void AssumptionTracker::forgetCachedAssumptions(Function *F) {
+  CachedAssumeCalls.erase(F);
+}
+
+void AssumptionTracker::CallCallbackVH::deleted() {
+  assert(F && "delete callback called on dummy handle");
+  FunctionCallsMap::iterator I = AT->CachedAssumeCalls.find(F);
+  assert(I != AT->CachedAssumeCalls.end() &&
+         "Function cleared from the map without removing the values?");
+
+  I->second->erase(*this);
+  // 'this' now dangles!
+}
+
+AssumptionTracker::FunctionCallsMap::iterator
+AssumptionTracker::scanFunction(Function *F) {
+  auto IP =
+    CachedAssumeCalls.insert(std::make_pair(FunctionCallbackVH(F, this),
+                                            std::unique_ptr<CallHandleSet>(
+                                              new CallHandleSet())));
+  assert(IP.second && "Scanning function already in the map?");
+
+  FunctionCallsMap::iterator I = IP.first;
+
+  // Go through all instructions in all blocks, add all calls to @llvm.assume
+  // to our cache.
+  for (BasicBlock &B : *F)
+    for (Instruction &II : B)
+      if (match(cast<Value>(&II), m_Intrinsic<Intrinsic::assume>(m_Value())))
+        I->second->insert(CallCallbackVH(&II, this));
+
+  return I;
+}
+
+void AssumptionTracker::verifyAnalysis() const {
+#ifndef NDEBUG
+  for (const auto &I : CachedAssumeCalls) {
+    for (const BasicBlock &B : cast<Function>(*I.first))
+      for (const Instruction &II : B) {
+        Instruction *C = const_cast<Instruction*>(&II);
+        if (match(C, m_Intrinsic<Intrinsic::assume>(m_Value()))) {
+          assert(I.second->count(CallCallbackVH(C,
+                   const_cast<AssumptionTracker*>(this))) &&
+                 "Assumption in scanned function not in cache");
+        }
+    }
+  }
+#endif
+}
+
+void AssumptionTracker::registerAssumption(CallInst *CI) {
+  assert(match(cast<Value>(CI),
+               m_Intrinsic<Intrinsic::assume>(m_Value())) &&
+         "Registered call does not call @llvm.assume");
+  assert(CI->getParent() &&
+         "Cannot register @llvm.assume call not in a basic block");
+
+  Function *F = CI->getParent()->getParent();
+  assert(F && "Cannot register @llvm.assume call not in a function");
+
+  FunctionCallsMap::iterator I = CachedAssumeCalls.find(F);
+  if (I == CachedAssumeCalls.end()) {
+    // If this function has not already been scanned, then don't do anything
+    // here. This intrinsic will be found, if it still exists, if the list of
+    // assumptions in this function is requested at some later point. This
+    // maintains the following invariant: if a function is present in the
+    // cache, then its list of assumption intrinsic calls is complete.
+    return;
+  }
+
+  I->second->insert(CallCallbackVH(CI, this));
+}
+
+AssumptionTracker::AssumptionTracker() : ImmutablePass(ID) {
+  initializeAssumptionTrackerPass(*PassRegistry::getPassRegistry());
+}
+
+AssumptionTracker::~AssumptionTracker() {}
+
+INITIALIZE_PASS(AssumptionTracker, "assumption-tracker", "Assumption Tracker",
+                false, true)
+char AssumptionTracker::ID = 0;
+

lib/Analysis/CMakeLists.txt

@@ -5,6 +5,7 @@ add_llvm_library(LLVMAnalysis
   AliasDebugger.cpp
   AliasSetTracker.cpp
   Analysis.cpp
+  AssumptionTracker.cpp
   BasicAliasAnalysis.cpp
   BlockFrequencyInfo.cpp
   BlockFrequencyInfoImpl.cpp

lib/Transforms/IPO/InlineAlways.cpp

@@ -15,6 +15,7 @@
 #include "llvm/Transforms/IPO.h"
 #include "llvm/ADT/SmallPtrSet.h"
 #include "llvm/Analysis/AliasAnalysis.h"
+#include "llvm/Analysis/AssumptionTracker.h"
 #include "llvm/Analysis/CallGraph.h"
 #include "llvm/Analysis/InlineCost.h"
 #include "llvm/IR/CallSite.h"
@@ -67,6 +68,7 @@ char AlwaysInliner::ID = 0;
 INITIALIZE_PASS_BEGIN(AlwaysInliner, "always-inline",
                 "Inliner for always_inline functions", false, false)
 INITIALIZE_AG_DEPENDENCY(AliasAnalysis)
+INITIALIZE_PASS_DEPENDENCY(AssumptionTracker)
 INITIALIZE_PASS_DEPENDENCY(CallGraphWrapperPass)
 INITIALIZE_PASS_DEPENDENCY(InlineCostAnalysis)
 INITIALIZE_PASS_END(AlwaysInliner, "always-inline",

lib/Transforms/IPO/InlineSimple.cpp

@@ -13,6 +13,7 @@
 
 #include "llvm/Transforms/IPO.h"
 #include "llvm/Analysis/AliasAnalysis.h"
+#include "llvm/Analysis/AssumptionTracker.h"
 #include "llvm/Analysis/CallGraph.h"
 #include "llvm/Analysis/InlineCost.h"
 #include "llvm/IR/CallSite.h"
@@ -75,6 +76,7 @@ char SimpleInliner::ID = 0;
 INITIALIZE_PASS_BEGIN(SimpleInliner, "inline",
                 "Function Integration/Inlining", false, false)
 INITIALIZE_AG_DEPENDENCY(AliasAnalysis)
+INITIALIZE_PASS_DEPENDENCY(AssumptionTracker)
 INITIALIZE_PASS_DEPENDENCY(CallGraphWrapperPass)
 INITIALIZE_PASS_DEPENDENCY(InlineCostAnalysis)
 INITIALIZE_PASS_END(SimpleInliner, "inline",

lib/Transforms/IPO/Inliner.cpp

@@ -17,6 +17,7 @@
 #include "llvm/ADT/SmallPtrSet.h"
 #include "llvm/ADT/Statistic.h"
 #include "llvm/Analysis/AliasAnalysis.h"
+#include "llvm/Analysis/AssumptionTracker.h"
 #include "llvm/Analysis/CallGraph.h"
 #include "llvm/Analysis/InlineCost.h"
 #include "llvm/IR/CallSite.h"
@@ -76,6 +77,7 @@ Inliner::Inliner(char &ID, int Threshold, bool InsertLifetime)
 /// always explicitly call the implementation here.
 void Inliner::getAnalysisUsage(AnalysisUsage &AU) const {
   AU.addRequired<AliasAnalysis>();
+  AU.addRequired<AssumptionTracker>();
   CallGraphSCCPass::getAnalysisUsage(AU);
 }
 
@@ -441,6 +443,7 @@ static bool InlineHistoryIncludes(Function *F, int InlineHistoryID,
 
 bool Inliner::runOnSCC(CallGraphSCC &SCC) {
   CallGraph &CG = getAnalysis<CallGraphWrapperPass>().getCallGraph();
+  AssumptionTracker *AT = &getAnalysis<AssumptionTracker>();
   DataLayoutPass *DLP = getAnalysisIfAvailable<DataLayoutPass>();
   const DataLayout *DL = DLP ? &DLP->getDataLayout() : nullptr;
   const TargetLibraryInfo *TLI = getAnalysisIfAvailable<TargetLibraryInfo>();
@@ -503,7 +506,7 @@ bool Inliner::runOnSCC(CallGraphSCC &SCC) {
 
   
   InlinedArrayAllocasTy InlinedArrayAllocas;
-  InlineFunctionInfo InlineInfo(&CG, DL, AA);
+  InlineFunctionInfo InlineInfo(&CG, DL, AA, AT);
   
   // Now that we have all of the call sites, loop over them and inline them if
   // it looks profitable to do so.

lib/Transforms/InstCombine/InstCombine.h

@@ -11,12 +11,14 @@
 #define LLVM_LIB_TRANSFORMS_INSTCOMBINE_INSTCOMBINE_H
 
 #include "InstCombineWorklist.h"
+#include "llvm/Analysis/AssumptionTracker.h"
 #include "llvm/Analysis/TargetFolder.h"
 #include "llvm/Analysis/ValueTracking.h"
 #include "llvm/IR/IRBuilder.h"
 #include "llvm/IR/InstVisitor.h"
 #include "llvm/IR/IntrinsicInst.h"
 #include "llvm/IR/Operator.h"
+#include "llvm/IR/PatternMatch.h"
 #include "llvm/Pass.h"
 #include "llvm/Transforms/Utils/SimplifyLibCalls.h"
 
@@ -71,14 +73,20 @@ static inline Constant *SubOne(Constant *C) {
 class LLVM_LIBRARY_VISIBILITY InstCombineIRInserter
     : public IRBuilderDefaultInserter<true> {
   InstCombineWorklist &Worklist;
+  AssumptionTracker *AT;
 
 public:
-  InstCombineIRInserter(InstCombineWorklist &WL) : Worklist(WL) {}
+  InstCombineIRInserter(InstCombineWorklist &WL, AssumptionTracker *AT)
+    : Worklist(WL), AT(AT) {}
 
   void InsertHelper(Instruction *I, const Twine &Name, BasicBlock *BB,
                     BasicBlock::iterator InsertPt) const {
     IRBuilderDefaultInserter<true>::InsertHelper(I, Name, BB, InsertPt);
     Worklist.Add(I);
+
+    using namespace llvm::PatternMatch;
+    if ((match(I, m_Intrinsic<Intrinsic::assume>(m_Value()))))
+      AT->registerAssumption(cast<CallInst>(I));
   }
 };
 
@@ -86,6 +94,7 @@ public:
 class LLVM_LIBRARY_VISIBILITY InstCombiner
     : public FunctionPass,
       public InstVisitor<InstCombiner, Instruction *> {
+  AssumptionTracker *AT;
   const DataLayout *DL;
   TargetLibraryInfo *TLI;
   bool MadeIRChange;
@@ -114,6 +123,8 @@ public:
 
   void getAnalysisUsage(AnalysisUsage &AU) const override;
 
+  AssumptionTracker *getAssumptionTracker() const { return AT; }
+
   const DataLayout *getDataLayout() const { return DL; }
 
   TargetLibraryInfo *getTargetLibraryInfo() const { return TLI; }

lib/Transforms/InstCombine/InstCombineCalls.cpp

@@ -996,6 +996,8 @@ Instruction *InstCombiner::visitCallInst(CallInst &CI) {
   }
   case Intrinsic::assume: {
     // Canonicalize assume(a && b) -> assume(a); assume(b);
+    // Note: New assumption intrinsics created here are registered by
+    // the InstCombineIRInserter object.
     Value *IIOperand = II->getArgOperand(0), *A, *B,
           *AssumeIntrinsic = II->getCalledValue();
     if (match(IIOperand, m_And(m_Value(A), m_Value(B)))) {
@@ -1005,8 +1007,10 @@ Instruction *InstCombiner::visitCallInst(CallInst &CI) {
     }
     // assume(!(a || b)) -> assume(!a); assume(!b);
     if (match(IIOperand, m_Not(m_Or(m_Value(A), m_Value(B))))) {
-      Builder->CreateCall(AssumeIntrinsic, Builder->CreateNot(A), II->getName());
-      Builder->CreateCall(AssumeIntrinsic, Builder->CreateNot(B), II->getName());
+      Builder->CreateCall(AssumeIntrinsic, Builder->CreateNot(A),
+                          II->getName());
+      Builder->CreateCall(AssumeIntrinsic, Builder->CreateNot(B),
+                          II->getName());
       return EraseInstFromFunction(*II);
     }
     break;

lib/Transforms/InstCombine/InstructionCombining.cpp

@@ -39,6 +39,7 @@
 #include "llvm/ADT/SmallPtrSet.h"
 #include "llvm/ADT/Statistic.h"
 #include "llvm/ADT/StringSwitch.h"
+#include "llvm/Analysis/AssumptionTracker.h"
 #include "llvm/Analysis/ConstantFolding.h"
 #include "llvm/Analysis/InstructionSimplify.h"
 #include "llvm/Analysis/MemoryBuiltins.h"
@@ -85,12 +86,14 @@ void LLVMInitializeInstCombine(LLVMPassRegistryRef R) {
 char InstCombiner::ID = 0;
 INITIALIZE_PASS_BEGIN(InstCombiner, "instcombine",
                 "Combine redundant instructions", false, false)
+INITIALIZE_PASS_DEPENDENCY(AssumptionTracker)
 INITIALIZE_PASS_DEPENDENCY(TargetLibraryInfo)
 INITIALIZE_PASS_END(InstCombiner, "instcombine",
                 "Combine redundant instructions", false, false)
 
 void InstCombiner::getAnalysisUsage(AnalysisUsage &AU) const {
   AU.setPreservesCFG();
+  AU.addRequired<AssumptionTracker>();
   AU.addRequired<TargetLibraryInfo>();
 }
 
@@ -2907,6 +2910,7 @@ bool InstCombiner::runOnFunction(Function &F) {
   if (skipOptnoneFunction(F))
     return false;
 
+  AT = &getAnalysis<AssumptionTracker>();
   DataLayoutPass *DLP = getAnalysisIfAvailable<DataLayoutPass>();
   DL = DLP ? &DLP->getDataLayout() : nullptr;
   TLI = &getAnalysis<TargetLibraryInfo>();
@@ -2918,7 +2922,7 @@ bool InstCombiner::runOnFunction(Function &F) {
   /// instructions into the worklist when they are created.
   IRBuilder<true, TargetFolder, InstCombineIRInserter>
     TheBuilder(F.getContext(), TargetFolder(DL),
-               InstCombineIRInserter(Worklist));
+               InstCombineIRInserter(Worklist, AT));
   Builder = &TheBuilder;
 
   InstCombinerLibCallSimplifier TheSimplifier(DL, TLI, this);

lib/Transforms/Scalar/LoopUnrollPass.cpp

@@ -13,6 +13,7 @@
 //===----------------------------------------------------------------------===//
 
 #include "llvm/Transforms/Scalar.h"
+#include "llvm/Analysis/AssumptionTracker.h"
 #include "llvm/Analysis/CodeMetrics.h"
 #include "llvm/Analysis/LoopPass.h"
 #include "llvm/Analysis/ScalarEvolution.h"
@@ -102,6 +103,7 @@ namespace {
     /// loop preheaders be inserted into the CFG...
     ///
     void getAnalysisUsage(AnalysisUsage &AU) const override {
+      AU.addRequired<AssumptionTracker>();
       AU.addRequired<LoopInfo>();
       AU.addPreserved<LoopInfo>();
       AU.addRequiredID(LoopSimplifyID);
@@ -182,6 +184,7 @@ namespace {
 char LoopUnroll::ID = 0;
 INITIALIZE_PASS_BEGIN(LoopUnroll, "loop-unroll", "Unroll loops", false, false)
 INITIALIZE_AG_DEPENDENCY(TargetTransformInfo)
+INITIALIZE_PASS_DEPENDENCY(AssumptionTracker)
 INITIALIZE_PASS_DEPENDENCY(LoopInfo)
 INITIALIZE_PASS_DEPENDENCY(LoopSimplify)
 INITIALIZE_PASS_DEPENDENCY(LCSSA)
@@ -351,6 +354,7 @@ bool LoopUnroll::runOnLoop(Loop *L, LPPassManager &LPM) {
   LoopInfo *LI = &getAnalysis<LoopInfo>();
   ScalarEvolution *SE = &getAnalysis<ScalarEvolution>();
   const TargetTransformInfo &TTI = getAnalysis<TargetTransformInfo>();
+  AssumptionTracker *AT = &getAnalysis<AssumptionTracker>();
 
   BasicBlock *Header = L->getHeader();
   DEBUG(dbgs() << "Loop Unroll: F[" << Header->getParent()->getName()
@@ -493,7 +497,8 @@ bool LoopUnroll::runOnLoop(Loop *L, LPPassManager &LPM) {
   }
 
   // Unroll the loop.
-  if (!UnrollLoop(L, Count, TripCount, AllowRuntime, TripMultiple, LI, this, &LPM))
+  if (!UnrollLoop(L, Count, TripCount, AllowRuntime, TripMultiple, LI, this,
+                  &LPM, AT))
     return false;
 
   return true;

lib/Transforms/Scalar/LoopUnswitch.cpp

@@ -30,6 +30,7 @@
 #include "llvm/ADT/STLExtras.h"
 #include "llvm/ADT/SmallPtrSet.h"
 #include "llvm/ADT/Statistic.h"
+#include "llvm/Analysis/AssumptionTracker.h"
 #include "llvm/Analysis/CodeMetrics.h"
 #include "llvm/Analysis/InstructionSimplify.h"
 #include "llvm/Analysis/LoopInfo.h"
@@ -126,6 +127,7 @@ namespace {
   class LoopUnswitch : public LoopPass {
     LoopInfo *LI;  // Loop information
     LPPassManager *LPM;
+    AssumptionTracker *AT;
 
     // LoopProcessWorklist - Used to check if second loop needs processing
     // after RewriteLoopBodyWithConditionConstant rewrites first loop.
@@ -164,6 +166,7 @@ namespace {
     /// loop preheaders be inserted into the CFG.
     ///
     void getAnalysisUsage(AnalysisUsage &AU) const override {
+      AU.addRequired<AssumptionTracker>();
       AU.addRequiredID(LoopSimplifyID);
       AU.addPreservedID(LoopSimplifyID);
       AU.addRequired<LoopInfo>();
@@ -326,6 +329,7 @@ char LoopUnswitch::ID = 0;
 INITIALIZE_PASS_BEGIN(LoopUnswitch, "loop-unswitch", "Unswitch loops",
                       false, false)
 INITIALIZE_AG_DEPENDENCY(TargetTransformInfo)
+INITIALIZE_PASS_DEPENDENCY(AssumptionTracker)
 INITIALIZE_PASS_DEPENDENCY(LoopSimplify)
 INITIALIZE_PASS_DEPENDENCY(LoopInfo)
 INITIALIZE_PASS_DEPENDENCY(LCSSA)
@@ -376,6 +380,7 @@ bool LoopUnswitch::runOnLoop(Loop *L, LPPassManager &LPM_Ref) {
   if (skipOptnoneFunction(L))
     return false;
 
+  AT = &getAnalysis<AssumptionTracker>();
   LI = &getAnalysis<LoopInfo>();
   LPM = &LPM_Ref;
   DominatorTreeWrapperPass *DTWP =
@@ -823,6 +828,10 @@ void LoopUnswitch::UnswitchNontrivialCondition(Value *LIC, Constant *Val,
   F->getBasicBlockList().splice(NewPreheader, F->getBasicBlockList(),
                                 NewBlocks[0], F->end());
 
+  // FIXME: We could register any cloned assumptions instead of clearing the
+  // whole function's cache.
+  AT->forgetCachedAssumptions(F);
+
   // Now we create the new Loop object for the versioned loop.
   Loop *NewLoop = CloneLoop(L, L->getParentLoop(), VMap, LI, LPM);
 

lib/Transforms/Utils/InlineFunction.cpp

@@ -18,6 +18,7 @@
 #include "llvm/ADT/SetVector.h"
 #include "llvm/ADT/StringExtras.h"
 #include "llvm/Analysis/AliasAnalysis.h"
+#include "llvm/Analysis/AssumptionTracker.h"
 #include "llvm/Analysis/CallGraph.h"
 #include "llvm/Analysis/CaptureTracking.h"
 #include "llvm/Analysis/InstructionSimplify.h"
@@ -982,6 +983,11 @@ bool llvm::InlineFunction(CallSite CS, InlineFunctionInfo &IFI,
 
     // Add noalias metadata if necessary.
     AddAliasScopeMetadata(CS, VMap, IFI.DL, IFI.AA);
+
+    // FIXME: We could register any cloned assumptions instead of clearing the
+    // whole function's cache.
+    if (IFI.AT)
+      IFI.AT->forgetCachedAssumptions(Caller);
   }
 
   // If there are any alloca instructions in the block that used to be the entry

lib/Transforms/Utils/LoopUnroll.cpp

@@ -19,6 +19,7 @@
 #include "llvm/Transforms/Utils/UnrollLoop.h"
 #include "llvm/ADT/SmallPtrSet.h"
 #include "llvm/ADT/Statistic.h"
+#include "llvm/Analysis/AssumptionTracker.h"
 #include "llvm/Analysis/InstructionSimplify.h"
 #include "llvm/Analysis/LoopIterator.h"
 #include "llvm/Analysis/LoopPass.h"
@@ -154,7 +155,8 @@ FoldBlockIntoPredecessor(BasicBlock *BB, LoopInfo* LI, LPPassManager *LPM,
 /// available from the Pass it must also preserve those analyses.
 bool llvm::UnrollLoop(Loop *L, unsigned Count, unsigned TripCount,
                       bool AllowRuntime, unsigned TripMultiple,
-                      LoopInfo *LI, Pass *PP, LPPassManager *LPM) {
+                      LoopInfo *LI, Pass *PP, LPPassManager *LPM,
+                      AssumptionTracker *AT) {
   BasicBlock *Preheader = L->getLoopPreheader();
   if (!Preheader) {
     DEBUG(dbgs() << "  Can't unroll; loop preheader-insertion failed.\n");
@@ -442,6 +444,10 @@ bool llvm::UnrollLoop(Loop *L, unsigned Count, unsigned TripCount,
     }
   }
 
+  // FIXME: We could register any cloned assumptions instead of clearing the
+  // whole function's cache.
+  AT->forgetCachedAssumptions(F);
+
   DominatorTree *DT = nullptr;
   if (PP) {
     // FIXME: Reconstruct dom info, because it is not preserved properly.