[PM/AA] Simplify the AliasAnalysis interface by removing a wrapper

around a DataLayout interface in favor of directly querying DataLayout.

This wrapper specifically helped handle the case where this no
DataLayout, but LLVM now requires it simplifynig all of this. I've
updated callers to directly query DataLayout. This in turn exposed
a bunch of places where we should have DataLayout readily available but
don't which I've fixed. This then in turn exposed that we were passing
DataLayout around in a bunch of arguments rather than making it readily
available so I've also fixed that.

No functionality changed.

llvm-svn: 244189

5 files changed, 63 insertions, 66 deletions

diff --git a/llvm/lib/Analysis/AliasAnalysis.cpp b/llvm/lib/Analysis/AliasAnalysis.cpp
index 43f6622a994..4d4a30290f4 100644
--- a/llvm/lib/Analysis/AliasAnalysis.cpp
+++ b/llvm/lib/Analysis/AliasAnalysis.cpp
@@ -416,13 +416,6 @@ void AliasAnalysis::getAnalysisUsage(AnalysisUsage &AU) const {
   AU.addRequired<AliasAnalysis>();         // All AA's chain
 }
 
-/// getTypeStoreSize - Return the DataLayout store size for the given type,
-/// if known, or a conservative value otherwise.
-///
-uint64_t AliasAnalysis::getTypeStoreSize(Type *Ty) {
-  return DL ? DL->getTypeStoreSize(Ty) : MemoryLocation::UnknownSize;
-}
-
 /// canBasicBlockModify - Return true if it is possible for execution of the
 /// specified basic block to modify the location Loc.
 ///
diff --git a/llvm/lib/Analysis/AliasAnalysisEvaluator.cpp b/llvm/lib/Analysis/AliasAnalysisEvaluator.cpp
index 7114a96c4ec..4540823dbed 100644
--- a/llvm/lib/Analysis/AliasAnalysisEvaluator.cpp
+++ b/llvm/lib/Analysis/AliasAnalysisEvaluator.cpp
@@ -21,8 +21,10 @@
 #include "llvm/ADT/SetVector.h"
 #include "llvm/Analysis/AliasAnalysis.h"
 #include "llvm/IR/Constants.h"
+#include "llvm/IR/DataLayout.h"
 #include "llvm/IR/DerivedTypes.h"
 #include "llvm/IR/Function.h"
+#include "llvm/IR/Module.h"
 #include "llvm/IR/InstIterator.h"
 #include "llvm/IR/Instructions.h"
 #include "llvm/Pass.h"
@@ -139,6 +141,7 @@ static inline bool isInterestingPointer(Value *V) {
 }
 
 bool AAEval::runOnFunction(Function &F) {
+  const DataLayout &DL = F.getParent()->getDataLayout();
   AliasAnalysis &AA = getAnalysis<AliasAnalysis>();
 
   SetVector<Value *> Pointers;
@@ -188,12 +191,12 @@ bool AAEval::runOnFunction(Function &F) {
        I1 != E; ++I1) {
     uint64_t I1Size = MemoryLocation::UnknownSize;
     Type *I1ElTy = cast<PointerType>((*I1)->getType())->getElementType();
-    if (I1ElTy->isSized()) I1Size = AA.getTypeStoreSize(I1ElTy);
+    if (I1ElTy->isSized()) I1Size = DL.getTypeStoreSize(I1ElTy);
 
     for (SetVector<Value *>::iterator I2 = Pointers.begin(); I2 != I1; ++I2) {
       uint64_t I2Size = MemoryLocation::UnknownSize;
       Type *I2ElTy =cast<PointerType>((*I2)->getType())->getElementType();
-      if (I2ElTy->isSized()) I2Size = AA.getTypeStoreSize(I2ElTy);
+      if (I2ElTy->isSized()) I2Size = DL.getTypeStoreSize(I2ElTy);
 
       switch (AA.alias(*I1, I1Size, *I2, I2Size)) {
       case NoAlias:
@@ -289,7 +292,7 @@ bool AAEval::runOnFunction(Function &F) {
          V != Ve; ++V) {
       uint64_t Size = MemoryLocation::UnknownSize;
       Type *ElTy = cast<PointerType>((*V)->getType())->getElementType();
-      if (ElTy->isSized()) Size = AA.getTypeStoreSize(ElTy);
+      if (ElTy->isSized()) Size = DL.getTypeStoreSize(ElTy);
 
       switch (AA.getModRefInfo(*C, *V, Size)) {
       case MRI_NoModRef:
diff --git a/llvm/lib/Analysis/AliasSetTracker.cpp b/llvm/lib/Analysis/AliasSetTracker.cpp
index 05bbe9b227d..f9d3126833b 100644
--- a/llvm/lib/Analysis/AliasSetTracker.cpp
+++ b/llvm/lib/Analysis/AliasSetTracker.cpp
@@ -17,6 +17,7 @@
 #include "llvm/IR/InstIterator.h"
 #include "llvm/IR/Instructions.h"
 #include "llvm/IR/IntrinsicInst.h"
+#include "llvm/IR/Module.h"
 #include "llvm/IR/LLVMContext.h"
 #include "llvm/IR/Type.h"
 #include "llvm/Pass.h"
@@ -306,8 +307,9 @@ bool AliasSetTracker::add(LoadInst *LI) {
 
   AliasSet::AccessLattice Access = AliasSet::RefAccess;
   bool NewPtr;
+  const DataLayout &DL = LI->getModule()->getDataLayout();
   AliasSet &AS = addPointer(LI->getOperand(0),
-                            AA.getTypeStoreSize(LI->getType()),
+                            DL.getTypeStoreSize(LI->getType()),
                             AAInfo, Access, NewPtr);
   if (LI->isVolatile()) AS.setVolatile();
   return NewPtr;
@@ -321,9 +323,10 @@ bool AliasSetTracker::add(StoreInst *SI) {
 
   AliasSet::AccessLattice Access = AliasSet::ModAccess;
   bool NewPtr;
+  const DataLayout &DL = SI->getModule()->getDataLayout();
   Value *Val = SI->getOperand(0);
   AliasSet &AS = addPointer(SI->getOperand(1),
-                            AA.getTypeStoreSize(Val->getType()),
+                            DL.getTypeStoreSize(Val->getType()),
                             AAInfo, Access, NewPtr);
   if (SI->isVolatile()) AS.setVolatile();
   return NewPtr;
@@ -440,7 +443,8 @@ AliasSetTracker::remove(Value *Ptr, uint64_t Size, const AAMDNodes &AAInfo) {
 }
 
 bool AliasSetTracker::remove(LoadInst *LI) {
-  uint64_t Size = AA.getTypeStoreSize(LI->getType());
+  const DataLayout &DL = LI->getModule()->getDataLayout();
+  uint64_t Size = DL.getTypeStoreSize(LI->getType());
 
   AAMDNodes AAInfo;
   LI->getAAMetadata(AAInfo);
@@ -452,7 +456,8 @@ bool AliasSetTracker::remove(LoadInst *LI) {
 }
 
 bool AliasSetTracker::remove(StoreInst *SI) {
-  uint64_t Size = AA.getTypeStoreSize(SI->getOperand(0)->getType());
+  const DataLayout &DL = SI->getModule()->getDataLayout();
+  uint64_t Size = DL.getTypeStoreSize(SI->getOperand(0)->getType());
 
   AAMDNodes AAInfo;
   SI->getAAMetadata(AAInfo);
diff --git a/llvm/lib/Analysis/DependenceAnalysis.cpp b/llvm/lib/Analysis/DependenceAnalysis.cpp
index 16e42ce6231..4ee82f0f134 100644
--- a/llvm/lib/Analysis/DependenceAnalysis.cpp
+++ b/llvm/lib/Analysis/DependenceAnalysis.cpp
@@ -631,8 +631,8 @@ static AliasResult underlyingObjectsAlias(AliasAnalysis *AA,
                                           const Value *B) {
   const Value *AObj = GetUnderlyingObject(A, DL);
   const Value *BObj = GetUnderlyingObject(B, DL);
-  return AA->alias(AObj, AA->getTypeStoreSize(AObj->getType()),
-                   BObj, AA->getTypeStoreSize(BObj->getType()));
+  return AA->alias(AObj, DL.getTypeStoreSize(AObj->getType()),
+                   BObj, DL.getTypeStoreSize(BObj->getType()));
 }
 
 
diff --git a/llvm/lib/Analysis/Lint.cpp b/llvm/lib/Analysis/Lint.cpp
index 0b9308a573a..ca277f56a25 100644
--- a/llvm/lib/Analysis/Lint.cpp
+++ b/llvm/lib/Analysis/Lint.cpp
@@ -49,6 +49,7 @@
 #include "llvm/IR/DataLayout.h"
 #include "llvm/IR/Dominators.h"
 #include "llvm/IR/Function.h"
+#include "llvm/IR/Module.h"
 #include "llvm/IR/InstVisitor.h"
 #include "llvm/IR/IntrinsicInst.h"
 #include "llvm/IR/LegacyPassManager.h"
@@ -98,12 +99,13 @@ namespace {
     void visitInsertElementInst(InsertElementInst &I);
     void visitUnreachableInst(UnreachableInst &I);
 
-    Value *findValue(Value *V, const DataLayout &DL, bool OffsetOk) const;
-    Value *findValueImpl(Value *V, const DataLayout &DL, bool OffsetOk,
+    Value *findValue(Value *V, bool OffsetOk) const;
+    Value *findValueImpl(Value *V, bool OffsetOk,
                          SmallPtrSetImpl<Value *> &Visited) const;
 
   public:
     Module *Mod;
+    const DataLayout *DL;
     AliasAnalysis *AA;
     AssumptionCache *AC;
     DominatorTree *DT;
@@ -178,6 +180,7 @@ INITIALIZE_PASS_END(Lint, "lint", "Statically lint-checks LLVM IR",
 //
 bool Lint::runOnFunction(Function &F) {
   Mod = F.getParent();
+  DL = &F.getParent()->getDataLayout();
   AA = &getAnalysis<AliasAnalysis>();
   AC = &getAnalysis<AssumptionCacheTracker>().getAssumptionCache(F);
   DT = &getAnalysis<DominatorTreeWrapperPass>().getDomTree();
@@ -200,12 +203,11 @@ void Lint::visitFunction(Function &F) {
 void Lint::visitCallSite(CallSite CS) {
   Instruction &I = *CS.getInstruction();
   Value *Callee = CS.getCalledValue();
-  const DataLayout &DL = CS->getModule()->getDataLayout();
 
   visitMemoryReference(I, Callee, MemoryLocation::UnknownSize, 0, nullptr,
                        MemRef::Callee);
 
-  if (Function *F = dyn_cast<Function>(findValue(Callee, DL,
+  if (Function *F = dyn_cast<Function>(findValue(Callee,
                                                  /*OffsetOk=*/false))) {
     Assert(CS.getCallingConv() == F->getCallingConv(),
            "Undefined behavior: Caller and callee calling convention differ",
@@ -253,8 +255,8 @@ void Lint::visitCallSite(CallSite CS) {
         if (Formal->hasStructRetAttr() && Actual->getType()->isPointerTy()) {
           Type *Ty =
             cast<PointerType>(Formal->getType())->getElementType();
-          visitMemoryReference(I, Actual, AA->getTypeStoreSize(Ty),
-                               DL.getABITypeAlignment(Ty), Ty,
+          visitMemoryReference(I, Actual, DL->getTypeStoreSize(Ty),
+                               DL->getABITypeAlignment(Ty), Ty,
                                MemRef::Read | MemRef::Write);
         }
       }
@@ -264,7 +266,7 @@ void Lint::visitCallSite(CallSite CS) {
   if (CS.isCall() && cast<CallInst>(CS.getInstruction())->isTailCall())
     for (CallSite::arg_iterator AI = CS.arg_begin(), AE = CS.arg_end();
          AI != AE; ++AI) {
-      Value *Obj = findValue(*AI, DL, /*OffsetOk=*/true);
+      Value *Obj = findValue(*AI, /*OffsetOk=*/true);
       Assert(!isa<AllocaInst>(Obj),
              "Undefined behavior: Call with \"tail\" keyword references "
              "alloca",
@@ -291,7 +293,7 @@ void Lint::visitCallSite(CallSite CS) {
       // overlap is not distinguished from the case where nothing is known.
       uint64_t Size = 0;
       if (const ConstantInt *Len =
-              dyn_cast<ConstantInt>(findValue(MCI->getLength(), DL,
+              dyn_cast<ConstantInt>(findValue(MCI->getLength(),
                                               /*OffsetOk=*/false)))
         if (Len->getValue().isIntN(32))
           Size = Len->getValue().getZExtValue();
@@ -367,8 +369,7 @@ void Lint::visitReturnInst(ReturnInst &I) {
          "Unusual: Return statement in function with noreturn attribute", &I);
 
   if (Value *V = I.getReturnValue()) {
-    Value *Obj =
-        findValue(V, F->getParent()->getDataLayout(), /*OffsetOk=*/true);
+    Value *Obj = findValue(V, /*OffsetOk=*/true);
     Assert(!isa<AllocaInst>(Obj), "Unusual: Returning alloca value", &I);
   }
 }
@@ -383,8 +384,7 @@ void Lint::visitMemoryReference(Instruction &I,
   if (Size == 0)
     return;
 
-  Value *UnderlyingObject =
-      findValue(Ptr, I.getModule()->getDataLayout(), /*OffsetOk=*/true);
+  Value *UnderlyingObject = findValue(Ptr, /*OffsetOk=*/true);
   Assert(!isa<ConstantPointerNull>(UnderlyingObject),
          "Undefined behavior: Null pointer dereference", &I);
   Assert(!isa<UndefValue>(UnderlyingObject),
@@ -423,9 +423,8 @@ void Lint::visitMemoryReference(Instruction &I,
   // Check for buffer overflows and misalignment.
   // Only handles memory references that read/write something simple like an
   // alloca instruction or a global variable.
-  auto &DL = I.getModule()->getDataLayout();
   int64_t Offset = 0;
-  if (Value *Base = GetPointerBaseWithConstantOffset(Ptr, Offset, DL)) {
+  if (Value *Base = GetPointerBaseWithConstantOffset(Ptr, Offset, *DL)) {
     // OK, so the access is to a constant offset from Ptr.  Check that Ptr is
     // something we can handle and if so extract the size of this base object
     // along with its alignment.
@@ -435,20 +434,20 @@ void Lint::visitMemoryReference(Instruction &I,
     if (AllocaInst *AI = dyn_cast<AllocaInst>(Base)) {
       Type *ATy = AI->getAllocatedType();
       if (!AI->isArrayAllocation() && ATy->isSized())
-        BaseSize = DL.getTypeAllocSize(ATy);
+        BaseSize = DL->getTypeAllocSize(ATy);
       BaseAlign = AI->getAlignment();
       if (BaseAlign == 0 && ATy->isSized())
-        BaseAlign = DL.getABITypeAlignment(ATy);
+        BaseAlign = DL->getABITypeAlignment(ATy);
     } else if (GlobalVariable *GV = dyn_cast<GlobalVariable>(Base)) {
       // If the global may be defined differently in another compilation unit
       // then don't warn about funky memory accesses.
       if (GV->hasDefinitiveInitializer()) {
         Type *GTy = GV->getType()->getElementType();
         if (GTy->isSized())
-          BaseSize = DL.getTypeAllocSize(GTy);
+          BaseSize = DL->getTypeAllocSize(GTy);
         BaseAlign = GV->getAlignment();
         if (BaseAlign == 0 && GTy->isSized())
-          BaseAlign = DL.getABITypeAlignment(GTy);
+          BaseAlign = DL->getABITypeAlignment(GTy);
       }
     }
 
@@ -462,7 +461,7 @@ void Lint::visitMemoryReference(Instruction &I,
     // Accesses that say that the memory is more aligned than it is are not
     // defined.
     if (Align == 0 && Ty && Ty->isSized())
-      Align = DL.getABITypeAlignment(Ty);
+      Align = DL->getABITypeAlignment(Ty);
     Assert(!BaseAlign || Align <= MinAlign(BaseAlign, Offset),
            "Undefined behavior: Memory reference address is misaligned", &I);
   }
@@ -470,13 +469,13 @@ void Lint::visitMemoryReference(Instruction &I,
 
 void Lint::visitLoadInst(LoadInst &I) {
   visitMemoryReference(I, I.getPointerOperand(),
-                       AA->getTypeStoreSize(I.getType()), I.getAlignment(),
+                       DL->getTypeStoreSize(I.getType()), I.getAlignment(),
                        I.getType(), MemRef::Read);
 }
 
 void Lint::visitStoreInst(StoreInst &I) {
   visitMemoryReference(I, I.getPointerOperand(),
-                       AA->getTypeStoreSize(I.getOperand(0)->getType()),
+                       DL->getTypeStoreSize(I.getOperand(0)->getType()),
                        I.getAlignment(),
                        I.getOperand(0)->getType(), MemRef::Write);
 }
@@ -492,23 +491,22 @@ void Lint::visitSub(BinaryOperator &I) {
 }
 
 void Lint::visitLShr(BinaryOperator &I) {
-  if (ConstantInt *CI = dyn_cast<ConstantInt>(
-          findValue(I.getOperand(1), I.getModule()->getDataLayout(),
-                    /*OffsetOk=*/false)))
+  if (ConstantInt *CI = dyn_cast<ConstantInt>(findValue(I.getOperand(1),
+                                                        /*OffsetOk=*/false)))
     Assert(CI->getValue().ult(cast<IntegerType>(I.getType())->getBitWidth()),
            "Undefined result: Shift count out of range", &I);
 }
 
 void Lint::visitAShr(BinaryOperator &I) {
-  if (ConstantInt *CI = dyn_cast<ConstantInt>(findValue(
-          I.getOperand(1), I.getModule()->getDataLayout(), /*OffsetOk=*/false)))
+  if (ConstantInt *CI =
+          dyn_cast<ConstantInt>(findValue(I.getOperand(1), /*OffsetOk=*/false)))
     Assert(CI->getValue().ult(cast<IntegerType>(I.getType())->getBitWidth()),
            "Undefined result: Shift count out of range", &I);
 }
 
 void Lint::visitShl(BinaryOperator &I) {
-  if (ConstantInt *CI = dyn_cast<ConstantInt>(findValue(
-          I.getOperand(1), I.getModule()->getDataLayout(), /*OffsetOk=*/false)))
+  if (ConstantInt *CI =
+          dyn_cast<ConstantInt>(findValue(I.getOperand(1), /*OffsetOk=*/false)))
     Assert(CI->getValue().ult(cast<IntegerType>(I.getType())->getBitWidth()),
            "Undefined result: Shift count out of range", &I);
 }
@@ -777,17 +775,15 @@ void Lint::visitIndirectBrInst(IndirectBrInst &I) {
 }
 
 void Lint::visitExtractElementInst(ExtractElementInst &I) {
-  if (ConstantInt *CI = dyn_cast<ConstantInt>(
-          findValue(I.getIndexOperand(), I.getModule()->getDataLayout(),
-                    /*OffsetOk=*/false)))
+  if (ConstantInt *CI = dyn_cast<ConstantInt>(findValue(I.getIndexOperand(),
+                                                        /*OffsetOk=*/false)))
     Assert(CI->getValue().ult(I.getVectorOperandType()->getNumElements()),
            "Undefined result: extractelement index out of range", &I);
 }
 
 void Lint::visitInsertElementInst(InsertElementInst &I) {
-  if (ConstantInt *CI = dyn_cast<ConstantInt>(
-          findValue(I.getOperand(2), I.getModule()->getDataLayout(),
-                    /*OffsetOk=*/false)))
+  if (ConstantInt *CI = dyn_cast<ConstantInt>(findValue(I.getOperand(2),
+                                                        /*OffsetOk=*/false)))
     Assert(CI->getValue().ult(I.getType()->getNumElements()),
            "Undefined result: insertelement index out of range", &I);
 }
@@ -808,13 +804,13 @@ void Lint::visitUnreachableInst(UnreachableInst &I) {
 /// Most analysis passes don't require this logic, because instcombine
 /// will simplify most of these kinds of things away. But it's a goal of
 /// this Lint pass to be useful even on non-optimized IR.
-Value *Lint::findValue(Value *V, const DataLayout &DL, bool OffsetOk) const {
+Value *Lint::findValue(Value *V, bool OffsetOk) const {
   SmallPtrSet<Value *, 4> Visited;
-  return findValueImpl(V, DL, OffsetOk, Visited);
+  return findValueImpl(V, OffsetOk, Visited);
 }
 
 /// findValueImpl - Implementation helper for findValue.
-Value *Lint::findValueImpl(Value *V, const DataLayout &DL, bool OffsetOk,
+Value *Lint::findValueImpl(Value *V, bool OffsetOk,
                            SmallPtrSetImpl<Value *> &Visited) const {
   // Detect self-referential values.
   if (!Visited.insert(V).second)
@@ -825,7 +821,7 @@ Value *Lint::findValueImpl(Value *V, const DataLayout &DL, bool OffsetOk,
   // TODO: Look through eliminable cast pairs.
   // TODO: Look through calls with unique return values.
   // TODO: Look through vector insert/extract/shuffle.
-  V = OffsetOk ? GetUnderlyingObject(V, DL) : V->stripPointerCasts();
+  V = OffsetOk ? GetUnderlyingObject(V, *DL) : V->stripPointerCasts();
   if (LoadInst *L = dyn_cast<LoadInst>(V)) {
     BasicBlock::iterator BBI = L;
     BasicBlock *BB = L->getParent();
@@ -835,7 +831,7 @@ Value *Lint::findValueImpl(Value *V, const DataLayout &DL, bool OffsetOk,
         break;
       if (Value *U = FindAvailableLoadedValue(L->getPointerOperand(),
                                               BB, BBI, 6, AA))
-        return findValueImpl(U, DL, OffsetOk, Visited);
+        return findValueImpl(U, OffsetOk, Visited);
       if (BBI != BB->begin()) break;
       BB = BB->getUniquePredecessor();
       if (!BB) break;
@@ -844,38 +840,38 @@ Value *Lint::findValueImpl(Value *V, const DataLayout &DL, bool OffsetOk,
   } else if (PHINode *PN = dyn_cast<PHINode>(V)) {
     if (Value *W = PN->hasConstantValue())
       if (W != V)
-        return findValueImpl(W, DL, OffsetOk, Visited);
+        return findValueImpl(W, OffsetOk, Visited);
   } else if (CastInst *CI = dyn_cast<CastInst>(V)) {
-    if (CI->isNoopCast(DL))
-      return findValueImpl(CI->getOperand(0), DL, OffsetOk, Visited);
+    if (CI->isNoopCast(*DL))
+      return findValueImpl(CI->getOperand(0), OffsetOk, Visited);
   } else if (ExtractValueInst *Ex = dyn_cast<ExtractValueInst>(V)) {
     if (Value *W = FindInsertedValue(Ex->getAggregateOperand(),
                                      Ex->getIndices()))
       if (W != V)
-        return findValueImpl(W, DL, OffsetOk, Visited);
+        return findValueImpl(W, OffsetOk, Visited);
   } else if (ConstantExpr *CE = dyn_cast<ConstantExpr>(V)) {
     // Same as above, but for ConstantExpr instead of Instruction.
     if (Instruction::isCast(CE->getOpcode())) {
       if (CastInst::isNoopCast(Instruction::CastOps(CE->getOpcode()),
                                CE->getOperand(0)->getType(), CE->getType(),
-                               DL.getIntPtrType(V->getType())))
-        return findValueImpl(CE->getOperand(0), DL, OffsetOk, Visited);
+                               DL->getIntPtrType(V->getType())))
+        return findValueImpl(CE->getOperand(0), OffsetOk, Visited);
     } else if (CE->getOpcode() == Instruction::ExtractValue) {
       ArrayRef<unsigned> Indices = CE->getIndices();
       if (Value *W = FindInsertedValue(CE->getOperand(0), Indices))
         if (W != V)
-          return findValueImpl(W, DL, OffsetOk, Visited);
+          return findValueImpl(W, OffsetOk, Visited);
     }
   }
 
   // As a last resort, try SimplifyInstruction or constant folding.
   if (Instruction *Inst = dyn_cast<Instruction>(V)) {
-    if (Value *W = SimplifyInstruction(Inst, DL, TLI, DT, AC))
-      return findValueImpl(W, DL, OffsetOk, Visited);
+    if (Value *W = SimplifyInstruction(Inst, *DL, TLI, DT, AC))
+      return findValueImpl(W, OffsetOk, Visited);
   } else if (ConstantExpr *CE = dyn_cast<ConstantExpr>(V)) {
-    if (Value *W = ConstantFoldConstantExpression(CE, DL, TLI))
+    if (Value *W = ConstantFoldConstantExpression(CE, *DL, TLI))
       if (W != V)
-        return findValueImpl(W, DL, OffsetOk, Visited);
+        return findValueImpl(W, OffsetOk, Visited);
   }
 
   return V;