Add "const" in GetUnderlyingObjects. NFC

Summary:
Both the input Value pointer and the returned Value
pointers in GetUnderlyingObjects are now declared as
const.

It turned out that all current (in-tree) uses of
GetUnderlyingObjects were trivial to update, being
satisfied with have those Value pointers declared
as const. Actually, in the past several of the users
had to use const_cast, just because of ValueTracking
not providing a version of GetUnderlyingObjects with
"const" Value pointers. With this patch we get rid
of those const casts.

Reviewers: hfinkel, materi, jkorous

Reviewed By: jkorous

Subscribers: dexonsmith, jkorous, jholewinski, sdardis, eraman, hiraditya, jrtc27, atanasyan, llvm-commits

Tags: #llvm

Differential Revision: https://reviews.llvm.org/D61038

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@359072 91177308-0d34-0410-b5e6-96231b3b80d8

include/llvm/Analysis/ValueTracking.h

@@ -351,7 +351,8 @@ class Value;
   /// Since A[i] and A[i-1] are independent pointers, getUnderlyingObjects
   /// should not assume that Curr and Prev share the same underlying object thus
   /// it shouldn't look through the phi above.
-  void GetUnderlyingObjects(Value *V, SmallVectorImpl<Value *> &Objects,
+  void GetUnderlyingObjects(const Value *V,
+                            SmallVectorImpl<const Value *> &Objects,
                             const DataLayout &DL, LoopInfo *LI = nullptr,
                             unsigned MaxLookup = 6);
 

lib/Analysis/GlobalsModRef.cpp

@@ -896,13 +896,13 @@ ModRefInfo GlobalsAAResult::getModRefInfoForArgument(const CallBase *Call,
   // Iterate through all the arguments to the called function. If any argument
   // is based on GV, return the conservative result.
   for (auto &A : Call->args()) {
-    SmallVector<Value*, 4> Objects;
+    SmallVector<const Value*, 4> Objects;
     GetUnderlyingObjects(A, Objects, DL);
 
     // All objects must be identified.
     if (!all_of(Objects, isIdentifiedObject) &&
         // Try ::alias to see if all objects are known not to alias GV.
-        !all_of(Objects, [&](Value *V) {
+        !all_of(Objects, [&](const Value *V) {
           return this->alias(MemoryLocation(V), MemoryLocation(GV), AAQI) ==
                  NoAlias;
         }))

lib/Analysis/InstructionSimplify.cpp

@@ -2281,12 +2281,12 @@ computePointerICmp(const DataLayout &DL, const TargetLibraryInfo *TLI,
     // come from a pointer that cannot overlap with dynamically-allocated
     // memory within the lifetime of the current function (allocas, byval
     // arguments, globals), then determine the comparison result here.
-    SmallVector<Value *, 8> LHSUObjs, RHSUObjs;
+    SmallVector<const Value *, 8> LHSUObjs, RHSUObjs;
     GetUnderlyingObjects(LHS, LHSUObjs, DL);
     GetUnderlyingObjects(RHS, RHSUObjs, DL);
 
     // Is the set of underlying objects all noalias calls?
-    auto IsNAC = [](ArrayRef<Value *> Objects) {
+    auto IsNAC = [](ArrayRef<const Value *> Objects) {
       return all_of(Objects, isNoAliasCall);
     };
 
@@ -2296,8 +2296,8 @@ computePointerICmp(const DataLayout &DL, const TargetLibraryInfo *TLI,
     // live with the compared-to allocation). For globals, we exclude symbols
     // that might be resolve lazily to symbols in another dynamically-loaded
     // library (and, thus, could be malloc'ed by the implementation).
-    auto IsAllocDisjoint = [](ArrayRef<Value *> Objects) {
-      return all_of(Objects, [](Value *V) {
+    auto IsAllocDisjoint = [](ArrayRef<const Value *> Objects) {
+      return all_of(Objects, [](const Value *V) {
         if (const AllocaInst *AI = dyn_cast<AllocaInst>(V))
           return AI->getParent() && AI->getFunction() && AI->isStaticAlloca();
         if (const GlobalValue *GV = dyn_cast<GlobalValue>(V))

lib/Analysis/LoopAccessAnalysis.cpp

@@ -842,7 +842,7 @@ void AccessAnalysis::processMemAccesses() {
     bool SetHasWrite = false;
 
     // Map of pointers to last access encountered.
-    typedef DenseMap<Value*, MemAccessInfo> UnderlyingObjToAccessMap;
+    typedef DenseMap<const Value*, MemAccessInfo> UnderlyingObjToAccessMap;
     UnderlyingObjToAccessMap ObjToLastAccess;
 
     // Set of access to check after all writes have been processed.
@@ -903,13 +903,13 @@ void AccessAnalysis::processMemAccesses() {
 
           // Create sets of pointers connected by a shared alias set and
           // underlying object.
-          typedef SmallVector<Value *, 16> ValueVector;
+          typedef SmallVector<const Value *, 16> ValueVector;
           ValueVector TempObjects;
 
           GetUnderlyingObjects(Ptr, TempObjects, DL, LI);
           LLVM_DEBUG(dbgs()
                      << "Underlying objects for pointer " << *Ptr << "\n");
-          for (Value *UnderlyingObj : TempObjects) {
+          for (const Value *UnderlyingObj : TempObjects) {
             // nullptr never alias, don't join sets for pointer that have "null"
             // in their UnderlyingObjects list.
             if (isa<ConstantPointerNull>(UnderlyingObj) &&

lib/Analysis/ValueTracking.cpp

@@ -3771,26 +3771,27 @@ Value *llvm::GetUnderlyingObject(Value *V, const DataLayout &DL,
   return V;
 }
 
-void llvm::GetUnderlyingObjects(Value *V, SmallVectorImpl<Value *> &Objects,
+void llvm::GetUnderlyingObjects(const Value *V,
+                                SmallVectorImpl<const Value *> &Objects,
                                 const DataLayout &DL, LoopInfo *LI,
                                 unsigned MaxLookup) {
-  SmallPtrSet<Value *, 4> Visited;
-  SmallVector<Value *, 4> Worklist;
+  SmallPtrSet<const Value *, 4> Visited;
+  SmallVector<const Value *, 4> Worklist;
   Worklist.push_back(V);
   do {
-    Value *P = Worklist.pop_back_val();
+    const Value *P = Worklist.pop_back_val();
     P = GetUnderlyingObject(P, DL, MaxLookup);
 
     if (!Visited.insert(P).second)
       continue;
 
-    if (SelectInst *SI = dyn_cast<SelectInst>(P)) {
+    if (auto *SI = dyn_cast<SelectInst>(P)) {
       Worklist.push_back(SI->getTrueValue());
       Worklist.push_back(SI->getFalseValue());
       continue;
     }
 
-    if (PHINode *PN = dyn_cast<PHINode>(P)) {
+    if (auto *PN = dyn_cast<PHINode>(P)) {
       // If this PHI changes the underlying object in every iteration of the
       // loop, don't look through it.  Consider:
       //   int **A;
@@ -3851,10 +3852,10 @@ bool llvm::getUnderlyingObjectsForCodeGen(const Value *V,
   do {
     V = Working.pop_back_val();
 
-    SmallVector<Value *, 4> Objs;
-    GetUnderlyingObjects(const_cast<Value *>(V), Objs, DL);
+    SmallVector<const Value *, 4> Objs;
+    GetUnderlyingObjects(V, Objs, DL);
 
-    for (Value *V : Objs) {
+    for (const Value *V : Objs) {
       if (!Visited.insert(V).second)
         continue;
       if (Operator::getOpcode(V) == Instruction::IntToPtr) {

lib/CodeGen/GlobalISel/IRTranslator.cpp

@@ -846,13 +846,13 @@ bool IRTranslator::translateKnownIntrinsic(const CallInst &CI, Intrinsic::ID ID,
 
     // Get the underlying objects for the location passed on the lifetime
     // marker.
-    SmallVector<Value *, 4> Allocas;
+    SmallVector<const Value *, 4> Allocas;
     GetUnderlyingObjects(CI.getArgOperand(1), Allocas, *DL);
 
     // Iterate over each underlying object, creating lifetime markers for each
     // static alloca. Quit if we find a non-static alloca.
-    for (Value *V : Allocas) {
-      AllocaInst *AI = dyn_cast<AllocaInst>(V);
+    for (const Value *V : Allocas) {
+      const AllocaInst *AI = dyn_cast<AllocaInst>(V);
       if (!AI)
         continue;
 

lib/CodeGen/MachinePipeliner.cpp

@@ -541,16 +541,16 @@ static bool isDependenceBarrier(MachineInstr &MI, AliasAnalysis *AA) {
 /// Return the underlying objects for the memory references of an instruction.
 /// This function calls the code in ValueTracking, but first checks that the
 /// instruction has a memory operand.
-static void getUnderlyingObjects(MachineInstr *MI,
-                                 SmallVectorImpl<Value *> &Objs,
+static void getUnderlyingObjects(const MachineInstr *MI,
+                                 SmallVectorImpl<const Value *> &Objs,
                                  const DataLayout &DL) {
   if (!MI->hasOneMemOperand())
     return;
   MachineMemOperand *MM = *MI->memoperands_begin();
   if (!MM->getValue())
     return;
-  GetUnderlyingObjects(const_cast<Value *>(MM->getValue()), Objs, DL);
-  for (Value *V : Objs) {
+  GetUnderlyingObjects(MM->getValue(), Objs, DL);
+  for (const Value *V : Objs) {
     if (!isIdentifiedObject(V)) {
       Objs.clear();
       return;
@@ -564,7 +564,7 @@ static void getUnderlyingObjects(MachineInstr *MI,
 /// dependence. This code is very similar to the code in ScheduleDAGInstrs
 /// but that code doesn't create loop carried dependences.
 void SwingSchedulerDAG::addLoopCarriedDependences(AliasAnalysis *AA) {
-  MapVector<Value *, SmallVector<SUnit *, 4>> PendingLoads;
+  MapVector<const Value *, SmallVector<SUnit *, 4>> PendingLoads;
   Value *UnknownValue =
     UndefValue::get(Type::getVoidTy(MF.getFunction().getContext()));
   for (auto &SU : SUnits) {
@@ -572,7 +572,7 @@ void SwingSchedulerDAG::addLoopCarriedDependences(AliasAnalysis *AA) {
     if (isDependenceBarrier(MI, AA))
       PendingLoads.clear();
     else if (MI.mayLoad()) {
-      SmallVector<Value *, 4> Objs;
+      SmallVector<const Value *, 4> Objs;
       getUnderlyingObjects(&MI, Objs, MF.getDataLayout());
       if (Objs.empty())
         Objs.push_back(UnknownValue);
@@ -581,12 +581,12 @@ void SwingSchedulerDAG::addLoopCarriedDependences(AliasAnalysis *AA) {
         SUs.push_back(&SU);
       }
     } else if (MI.mayStore()) {
-      SmallVector<Value *, 4> Objs;
+      SmallVector<const Value *, 4> Objs;
       getUnderlyingObjects(&MI, Objs, MF.getDataLayout());
       if (Objs.empty())
         Objs.push_back(UnknownValue);
       for (auto V : Objs) {
-        MapVector<Value *, SmallVector<SUnit *, 4>>::iterator I =
+        MapVector<const Value *, SmallVector<SUnit *, 4>>::iterator I =
             PendingLoads.find(V);
         if (I == PendingLoads.end())
           continue;

lib/CodeGen/SelectionDAG/SelectionDAGBuilder.cpp

@@ -6463,12 +6463,12 @@ SelectionDAGBuilder::visitIntrinsicCall(const CallInst &I, unsigned Intrinsic) {
     const int64_t ObjectSize =
         cast<ConstantInt>(I.getArgOperand(0))->getSExtValue();
     Value *const ObjectPtr = I.getArgOperand(1);
-    SmallVector<Value *, 4> Allocas;
+    SmallVector<const Value *, 4> Allocas;
     GetUnderlyingObjects(ObjectPtr, Allocas, *DL);
 
-    for (SmallVectorImpl<Value*>::iterator Object = Allocas.begin(),
+    for (SmallVectorImpl<const Value*>::iterator Object = Allocas.begin(),
            E = Allocas.end(); Object != E; ++Object) {
-      AllocaInst *LifetimeObject = dyn_cast_or_null<AllocaInst>(*Object);
+      const AllocaInst *LifetimeObject = dyn_cast_or_null<AllocaInst>(*Object);
 
       // Could not find an Alloca.
       if (!LifetimeObject)

lib/Target/Mips/MipsDelaySlotFiller.cpp

@@ -540,10 +540,10 @@ getUnderlyingObjects(const MachineInstr &MI,
 
   const Value *V = (*MI.memoperands_begin())->getValue();
 
-  SmallVector<Value *, 4> Objs;
-  GetUnderlyingObjects(const_cast<Value *>(V), Objs, DL);
+  SmallVector<const Value *, 4> Objs;
+  GetUnderlyingObjects(V, Objs, DL);
 
-  for (SmallVectorImpl<Value *>::iterator I = Objs.begin(), E = Objs.end();
+  for (SmallVectorImpl<const Value *>::iterator I = Objs.begin(), E = Objs.end();
        I != E; ++I) {
     if (!isIdentifiedObject(V))
       return false;

lib/Target/NVPTX/NVPTXISelDAGToDAG.cpp

@@ -701,11 +701,11 @@ static bool canLowerToLDG(MemSDNode *N, const NVPTXSubtarget &Subtarget,
   // We use GetUnderlyingObjects() here instead of GetUnderlyingObject() mainly
   // because the former looks through phi nodes while the latter does not. We
   // need to look through phi nodes to handle pointer induction variables.
-  SmallVector<Value *, 8> Objs;
-  GetUnderlyingObjects(const_cast<Value *>(N->getMemOperand()->getValue()),
+  SmallVector<const Value *, 8> Objs;
+  GetUnderlyingObjects(N->getMemOperand()->getValue(),
                        Objs, F->getDataLayout());
 
-  return all_of(Objs, [&](Value *V) {
+  return all_of(Objs, [&](const Value *V) {
     if (auto *A = dyn_cast<const Argument>(V))
       return IsKernelFn && A->onlyReadsMemory() && A->hasNoAliasAttr();
     if (auto *GV = dyn_cast<const GlobalVariable>(V))

lib/Transforms/Instrumentation/DataFlowSanitizer.cpp

@@ -1190,10 +1190,10 @@ Value *DFSanFunction::loadShadow(Value *Addr, uint64_t Size, uint64_t Align,
   }
 
   uint64_t ShadowAlign = Align * DFS.ShadowWidth / 8;
-  SmallVector<Value *, 2> Objs;
+  SmallVector<const Value *, 2> Objs;
   GetUnderlyingObjects(Addr, Objs, Pos->getModule()->getDataLayout());
   bool AllConstants = true;
-  for (Value *Obj : Objs) {
+  for (const Value *Obj : Objs) {
     if (isa<Function>(Obj) || isa<BlockAddress>(Obj))
       continue;
     if (isa<GlobalVariable>(Obj) && cast<GlobalVariable>(Obj)->isConstant())

lib/Transforms/Scalar/DeadStoreElimination.cpp

@@ -99,7 +99,7 @@ static void
 deleteDeadInstruction(Instruction *I, BasicBlock::iterator *BBI,
                       MemoryDependenceResults &MD, const TargetLibraryInfo &TLI,
                       InstOverlapIntervalsTy &IOL, OrderedBasicBlock &OBB,
-                      SmallSetVector<Value *, 16> *ValueSet = nullptr) {
+                      SmallSetVector<const Value *, 16> *ValueSet = nullptr) {
   SmallVector<Instruction*, 32> NowDeadInsts;
 
   NowDeadInsts.push_back(I);
@@ -713,7 +713,7 @@ static bool handleFree(CallInst *F, AliasAnalysis *AA,
 /// the DeadStackObjects set. If so, they become live because the location is
 /// being loaded.
 static void removeAccessedObjects(const MemoryLocation &LoadedLoc,
-                                  SmallSetVector<Value *, 16> &DeadStackObjects,
+                                  SmallSetVector<const Value *, 16> &DeadStackObjects,
                                   const DataLayout &DL, AliasAnalysis *AA,
                                   const TargetLibraryInfo *TLI,
                                   const Function *F) {
@@ -726,12 +726,12 @@ static void removeAccessedObjects(const MemoryLocation &LoadedLoc,
   // If the kill pointer can be easily reduced to an alloca, don't bother doing
   // extraneous AA queries.
   if (isa<AllocaInst>(UnderlyingPointer) || isa<Argument>(UnderlyingPointer)) {
-    DeadStackObjects.remove(const_cast<Value*>(UnderlyingPointer));
+    DeadStackObjects.remove(UnderlyingPointer);
     return;
   }
 
   // Remove objects that could alias LoadedLoc.
-  DeadStackObjects.remove_if([&](Value *I) {
+  DeadStackObjects.remove_if([&](const Value *I) {
     // See if the loaded location could alias the stack location.
     MemoryLocation StackLoc(I, getPointerSize(I, DL, *TLI, F));
     return !AA->isNoAlias(StackLoc, LoadedLoc);
@@ -753,7 +753,7 @@ static bool handleEndBlock(BasicBlock &BB, AliasAnalysis *AA,
 
   // Keep track of all of the stack objects that are dead at the end of the
   // function.
-  SmallSetVector<Value*, 16> DeadStackObjects;
+  SmallSetVector<const Value*, 16> DeadStackObjects;
 
   // Find all of the alloca'd pointers in the entry block.
   BasicBlock &Entry = BB.getParent()->front();
@@ -782,12 +782,12 @@ static bool handleEndBlock(BasicBlock &BB, AliasAnalysis *AA,
     // If we find a store, check to see if it points into a dead stack value.
     if (hasAnalyzableMemoryWrite(&*BBI, *TLI) && isRemovable(&*BBI)) {
       // See through pointer-to-pointer bitcasts
-      SmallVector<Value *, 4> Pointers;
+      SmallVector<const Value *, 4> Pointers;
       GetUnderlyingObjects(getStoredPointerOperand(&*BBI), Pointers, DL);
 
       // Stores to stack values are valid candidates for removal.
       bool AllDead = true;
-      for (Value *Pointer : Pointers)
+      for (const Value *Pointer : Pointers)
         if (!DeadStackObjects.count(Pointer)) {
           AllDead = false;
           break;
@@ -798,7 +798,8 @@ static bool handleEndBlock(BasicBlock &BB, AliasAnalysis *AA,
 
         LLVM_DEBUG(dbgs() << "DSE: Dead Store at End of Block:\n  DEAD: "
                           << *Dead << "\n  Objects: ";
-                   for (SmallVectorImpl<Value *>::iterator I = Pointers.begin(),
+                   for (SmallVectorImpl<const Value *>::iterator I =
+                            Pointers.begin(),
                         E = Pointers.end();
                         I != E; ++I) {
                      dbgs() << **I;
@@ -847,7 +848,7 @@ static bool handleEndBlock(BasicBlock &BB, AliasAnalysis *AA,
 
       // If the call might load from any of our allocas, then any store above
       // the call is live.
-      DeadStackObjects.remove_if([&](Value *I) {
+      DeadStackObjects.remove_if([&](const Value *I) {
         // See if the call site touches the value.
         return isRefSet(AA->getModRefInfo(
             Call, I, getPointerSize(I, DL, *TLI, BB.getParent())));

lib/Transforms/Utils/InlineFunction.cpp

@@ -1041,11 +1041,10 @@ static void AddAliasScopeMetadata(CallSite CS, ValueToValueMapTy &VMap,
 
       SmallSetVector<const Argument *, 4> NAPtrArgs;
       for (const Value *V : PtrArgs) {
-        SmallVector<Value *, 4> Objects;
-        GetUnderlyingObjects(const_cast<Value*>(V),
-                             Objects, DL, /* LI = */ nullptr);
+        SmallVector<const Value *, 4> Objects;
+        GetUnderlyingObjects(V, Objects, DL, /* LI = */ nullptr);
 
-        for (Value *O : Objects)
+        for (const Value *O : Objects)
           ObjSet.insert(O);
       }