Rename WeakVH to WeakTrackingVH; NFC

This relands r301424.

llvm-svn: 301812
diff --git a/llvm/lib/Transforms/Utils/BasicBlockUtils.cpp b/llvm/lib/Transforms/Utils/BasicBlockUtils.cpp
index 22af21d..3d5cbfc 100644
--- a/llvm/lib/Transforms/Utils/BasicBlockUtils.cpp
+++ b/llvm/lib/Transforms/Utils/BasicBlockUtils.cpp
@@ -78,8 +78,8 @@
 
 bool llvm::DeleteDeadPHIs(BasicBlock *BB, const TargetLibraryInfo *TLI) {
   // Recursively deleting a PHI may cause multiple PHIs to be deleted
-  // or RAUW'd undef, so use an array of WeakVH for the PHIs to delete.
-  SmallVector<WeakVH, 8> PHIs;
+  // or RAUW'd undef, so use an array of WeakTrackingVH for the PHIs to delete.
+  SmallVector<WeakTrackingVH, 8> PHIs;
   for (BasicBlock::iterator I = BB->begin();
        PHINode *PN = dyn_cast<PHINode>(I); ++I)
     PHIs.push_back(PN);
diff --git a/llvm/lib/Transforms/Utils/CloneFunction.cpp b/llvm/lib/Transforms/Utils/CloneFunction.cpp
index 385c123..d5124ac 100644
--- a/llvm/lib/Transforms/Utils/CloneFunction.cpp
+++ b/llvm/lib/Transforms/Utils/CloneFunction.cpp
@@ -245,7 +245,7 @@
 void PruningFunctionCloner::CloneBlock(const BasicBlock *BB,
                                        BasicBlock::const_iterator StartingInst,
                                        std::vector<const BasicBlock*> &ToClone){
-  WeakVH &BBEntry = VMap[BB];
+  WeakTrackingVH &BBEntry = VMap[BB];
 
   // Have we already cloned this block?
   if (BBEntry) return;
@@ -547,7 +547,7 @@
   // Make a second pass over the PHINodes now that all of them have been
   // remapped into the new function, simplifying the PHINode and performing any
   // recursive simplifications exposed. This will transparently update the
-  // WeakVH in the VMap. Notably, we rely on that so that if we coalesce
+  // WeakTrackingVH in the VMap. Notably, we rely on that so that if we coalesce
   // two PHINodes, the iteration over the old PHIs remains valid, and the
   // mapping will just map us to the new node (which may not even be a PHI
   // node).
diff --git a/llvm/lib/Transforms/Utils/Local.cpp b/llvm/lib/Transforms/Utils/Local.cpp
index 364b33d..ce6b703 100644
--- a/llvm/lib/Transforms/Utils/Local.cpp
+++ b/llvm/lib/Transforms/Utils/Local.cpp
@@ -562,7 +562,7 @@
   // that can be removed.
   BB->removePredecessor(Pred, true);
 
-  WeakVH PhiIt = &BB->front();
+  WeakTrackingVH PhiIt = &BB->front();
   while (PHINode *PN = dyn_cast<PHINode>(PhiIt)) {
     PhiIt = &*++BasicBlock::iterator(cast<Instruction>(PhiIt));
     Value *OldPhiIt = PhiIt;
@@ -1476,7 +1476,7 @@
   II->setAttributes(CI->getAttributes());
 
   // Make sure that anything using the call now uses the invoke!  This also
-  // updates the CallGraph if present, because it uses a WeakVH.
+  // updates the CallGraph if present, because it uses a WeakTrackingVH.
   CI->replaceAllUsesWith(II);
 
   // Delete the original call
diff --git a/llvm/lib/Transforms/Utils/LoopUnroll.cpp b/llvm/lib/Transforms/Utils/LoopUnroll.cpp
index 85684a0..4ab4d79 100644
--- a/llvm/lib/Transforms/Utils/LoopUnroll.cpp
+++ b/llvm/lib/Transforms/Utils/LoopUnroll.cpp
@@ -757,7 +757,7 @@
 
   // Simplify any new induction variables in the partially unrolled loop.
   if (SE && !CompletelyUnroll && Count > 1) {
-    SmallVector<WeakVH, 16> DeadInsts;
+    SmallVector<WeakTrackingVH, 16> DeadInsts;
     simplifyLoopIVs(L, SE, DT, LI, DeadInsts);
 
     // Aggressively clean up dead instructions that simplifyLoopIVs already
diff --git a/llvm/lib/Transforms/Utils/SimplifyIndVar.cpp b/llvm/lib/Transforms/Utils/SimplifyIndVar.cpp
index a4cc6a0..02a5d3d 100644
--- a/llvm/lib/Transforms/Utils/SimplifyIndVar.cpp
+++ b/llvm/lib/Transforms/Utils/SimplifyIndVar.cpp
@@ -51,13 +51,13 @@
     ScalarEvolution  *SE;
     DominatorTree    *DT;
 
-    SmallVectorImpl<WeakVH> &DeadInsts;
+    SmallVectorImpl<WeakTrackingVH> &DeadInsts;
 
     bool Changed;
 
   public:
     SimplifyIndvar(Loop *Loop, ScalarEvolution *SE, DominatorTree *DT,
-                   LoopInfo *LI,SmallVectorImpl<WeakVH> &Dead)
+                   LoopInfo *LI, SmallVectorImpl<WeakTrackingVH> &Dead)
         : L(Loop), LI(LI), SE(SE), DT(DT), DeadInsts(Dead), Changed(false) {
       assert(LI && "IV simplification requires LoopInfo");
     }
@@ -701,7 +701,7 @@
 /// Simplify instructions that use this induction variable
 /// by using ScalarEvolution to analyze the IV's recurrence.
 bool simplifyUsersOfIV(PHINode *CurrIV, ScalarEvolution *SE, DominatorTree *DT,
-                       LoopInfo *LI, SmallVectorImpl<WeakVH> &Dead,
+                       LoopInfo *LI, SmallVectorImpl<WeakTrackingVH> &Dead,
                        IVVisitor *V) {
   SimplifyIndvar SIV(LI->getLoopFor(CurrIV->getParent()), SE, DT, LI, Dead);
   SIV.simplifyUsers(CurrIV, V);
@@ -711,7 +711,7 @@
 /// Simplify users of induction variables within this
 /// loop. This does not actually change or add IVs.
 bool simplifyLoopIVs(Loop *L, ScalarEvolution *SE, DominatorTree *DT,
-                     LoopInfo *LI, SmallVectorImpl<WeakVH> &Dead) {
+                     LoopInfo *LI, SmallVectorImpl<WeakTrackingVH> &Dead) {
   bool Changed = false;
   for (BasicBlock::iterator I = L->getHeader()->begin(); isa<PHINode>(I); ++I) {
     Changed |= simplifyUsersOfIV(cast<PHINode>(I), SE, DT, LI, Dead);