commit be23012d5a84fefdb6d0a267f9ffb4bafb4804d7
Author: Kazu Hirata <kazu@google.com>
Date:   Sun Feb 7 09:49:36 2021 -0800

    [Transforms/Utils] Use range-based for loops (NFC)

diff --git a/llvm/lib/Transforms/Utils/CloneFunction.cpp b/llvm/lib/Transforms/Utils/CloneFunction.cpp
index 51a49574e55d..a953ba5c6b14 100644
--- a/llvm/lib/Transforms/Utils/CloneFunction.cpp
+++ b/llvm/lib/Transforms/Utils/CloneFunction.cpp
@@ -563,9 +563,8 @@ void llvm::CloneAndPruneIntoFromInst(Function *NewFunc, const Function *OldFunc,
       assert(NumPreds < PN->getNumIncomingValues());
       // Count how many times each predecessor comes to this block.
       std::map<BasicBlock*, unsigned> PredCount;
-      for (pred_iterator PI = pred_begin(NewBB), E = pred_end(NewBB);
-           PI != E; ++PI)
-        --PredCount[*PI];
+      for (BasicBlock *Pred : predecessors(NewBB))
+        --PredCount[Pred];
 
       // Figure out how many entries to remove from each PHI.
       for (unsigned i = 0, e = PN->getNumIncomingValues(); i != e; ++i)
diff --git a/llvm/lib/Transforms/Utils/CloneModule.cpp b/llvm/lib/Transforms/Utils/CloneModule.cpp
index a6327bbf21bc..6de679bc9640 100644
--- a/llvm/lib/Transforms/Utils/CloneModule.cpp
+++ b/llvm/lib/Transforms/Utils/CloneModule.cpp
@@ -115,28 +115,27 @@ std::unique_ptr<Module> llvm::CloneModule(
   // have been created, loop through and copy the global variable referrers
   // over...  We also set the attributes on the global now.
   //
-  for (Module::const_global_iterator I = M.global_begin(), E = M.global_end();
-       I != E; ++I) {
-    GlobalVariable *GV = cast<GlobalVariable>(VMap[&*I]);
+  for (const GlobalVariable &G : M.globals()) {
+    GlobalVariable *GV = cast<GlobalVariable>(VMap[&G]);
 
     SmallVector<std::pair<unsigned, MDNode *>, 1> MDs;
-    I->getAllMetadata(MDs);
+    G.getAllMetadata(MDs);
     for (auto MD : MDs)
       GV->addMetadata(MD.first,
                       *MapMetadata(MD.second, VMap, RF_MoveDistinctMDs));
 
-    if (I->isDeclaration())
+    if (G.isDeclaration())
       continue;
 
-    if (!ShouldCloneDefinition(&*I)) {
+    if (!ShouldCloneDefinition(&G)) {
       // Skip after setting the correct linkage for an external reference.
       GV->setLinkage(GlobalValue::ExternalLinkage);
       continue;
     }
-    if (I->hasInitializer())
-      GV->setInitializer(MapValue(I->getInitializer(), VMap));
+    if (G.hasInitializer())
+      GV->setInitializer(MapValue(G.getInitializer(), VMap));
 
-    copyComdat(GV, &*I);
+    copyComdat(GV, &G);
   }
 
   // Similarly, copy over function bodies now...
diff --git a/llvm/lib/Transforms/Utils/CodeExtractor.cpp b/llvm/lib/Transforms/Utils/CodeExtractor.cpp
index 461be91f2623..ec316dec9361 100644
--- a/llvm/lib/Transforms/Utils/CodeExtractor.cpp
+++ b/llvm/lib/Transforms/Utils/CodeExtractor.cpp
@@ -1611,15 +1611,14 @@ CodeExtractor::extractCodeRegion(const CodeExtractorAnalysisCache &CEAC) {
   DenseMap<BasicBlock *, BlockFrequency> ExitWeights;
   SmallPtrSet<BasicBlock *, 1> ExitBlocks;
   for (BasicBlock *Block : Blocks) {
-    for (succ_iterator SI = succ_begin(Block), SE = succ_end(Block); SI != SE;
-         ++SI) {
-      if (!Blocks.count(*SI)) {
+    for (BasicBlock *Succ : successors(Block)) {
+      if (!Blocks.count(Succ)) {
         // Update the branch weight for this successor.
         if (BFI) {
-          BlockFrequency &BF = ExitWeights[*SI];
-          BF += BFI->getBlockFreq(Block) * BPI->getEdgeProbability(Block, *SI);
+          BlockFrequency &BF = ExitWeights[Succ];
+          BF += BFI->getBlockFreq(Block) * BPI->getEdgeProbability(Block, Succ);
         }
-        ExitBlocks.insert(*SI);
+        ExitBlocks.insert(Succ);
       }
     }
   }
diff --git a/llvm/lib/Transforms/Utils/FixIrreducible.cpp b/llvm/lib/Transforms/Utils/FixIrreducible.cpp
index 44af95eef67d..10f48fe827f4 100644
--- a/llvm/lib/Transforms/Utils/FixIrreducible.cpp
+++ b/llvm/lib/Transforms/Utils/FixIrreducible.cpp
@@ -129,8 +129,7 @@ static void reconnectChildLoops(LoopInfo &LI, Loop *ParentLoop, Loop *NewLoop,
   SmallVector<Loop *, 8> ChildLoops(FirstChild, CandidateLoops.end());
   CandidateLoops.erase(FirstChild, CandidateLoops.end());
 
-  for (auto II = ChildLoops.begin(), IE = ChildLoops.end(); II != IE; ++II) {
-    auto Child = *II;
+  for (Loop *Child : ChildLoops) {
     LLVM_DEBUG(dbgs() << "child loop: " << Child->getHeader()->getName()
                       << "\n");
     // TODO: A child loop whose header is also a header in the current
diff --git a/llvm/lib/Transforms/Utils/Local.cpp b/llvm/lib/Transforms/Utils/Local.cpp
index 948bf08e7cfe..f8c792a34f0e 100644
--- a/llvm/lib/Transforms/Utils/Local.cpp
+++ b/llvm/lib/Transforms/Utils/Local.cpp
@@ -743,11 +743,11 @@ void llvm::MergeBasicBlockIntoOnlyPred(BasicBlock *DestBB,
   SmallVector<DominatorTree::UpdateType, 32> Updates;
 
   if (DTU) {
-    for (auto I = pred_begin(PredBB), E = pred_end(PredBB); I != E; ++I) {
+    for (BasicBlock *PredPredBB : predecessors(PredBB)) {
       // This predecessor of PredBB may already have DestBB as a successor.
-      if (!llvm::is_contained(successors(*I), DestBB))
-        Updates.push_back({DominatorTree::Insert, *I, DestBB});
-      Updates.push_back({DominatorTree::Delete, *I, PredBB});
+      if (!llvm::is_contained(successors(PredPredBB), DestBB))
+        Updates.push_back({DominatorTree::Insert, PredPredBB, DestBB});
+      Updates.push_back({DominatorTree::Delete, PredPredBB, PredBB});
     }
     Updates.push_back({DominatorTree::Delete, PredBB, DestBB});
   }
@@ -1040,8 +1040,8 @@ bool llvm::TryToSimplifyUncondBranchFromEmptyBlock(BasicBlock *BB,
 
   // We cannot fold the block if it's a branch to an already present callbr
   // successor because that creates duplicate successors.
-  for (auto I = pred_begin(BB), E = pred_end(BB); I != E; ++I) {
-    if (auto *CBI = dyn_cast<CallBrInst>((*I)->getTerminator())) {
+  for (BasicBlock *PredBB : predecessors(BB)) {
+    if (auto *CBI = dyn_cast<CallBrInst>(PredBB->getTerminator())) {
       if (Succ == CBI->getDefaultDest())
         return false;
       for (unsigned i = 0, e = CBI->getNumIndirectDests(); i != e; ++i)
@@ -1102,10 +1102,8 @@ bool llvm::TryToSimplifyUncondBranchFromEmptyBlock(BasicBlock *BB,
   Instruction *TI = BB->getTerminator();
   if (TI)
     if (MDNode *LoopMD = TI->getMetadata(LoopMDKind))
-      for (pred_iterator PI = pred_begin(BB), E = pred_end(BB); PI != E; ++PI) {
-        BasicBlock *Pred = *PI;
+      for (BasicBlock *Pred : predecessors(BB))
         Pred->getTerminator()->setMetadata(LoopMDKind, LoopMD);
-      }
 
   // Everything that jumped to BB now goes to Succ.
   BB->replaceAllUsesWith(Succ);
diff --git a/llvm/lib/Transforms/Utils/LoopSimplify.cpp b/llvm/lib/Transforms/Utils/LoopSimplify.cpp
index 2e104334ad96..6adfeaf4fd5f 100644
--- a/llvm/lib/Transforms/Utils/LoopSimplify.cpp
+++ b/llvm/lib/Transforms/Utils/LoopSimplify.cpp
@@ -127,9 +127,7 @@ BasicBlock *llvm::InsertPreheaderForLoop(Loop *L, DominatorTree *DT,
 
   // Compute the set of predecessors of the loop that are not in the loop.
   SmallVector<BasicBlock*, 8> OutsideBlocks;
-  for (pred_iterator PI = pred_begin(Header), PE = pred_end(Header);
-       PI != PE; ++PI) {
-    BasicBlock *P = *PI;
+  for (BasicBlock *P : predecessors(Header)) {
     if (!L->contains(P)) {         // Coming in from outside the loop?
       // If the loop is branched to from an indirect terminator, we won't
       // be able to fully transform the loop, because it prohibits
@@ -381,9 +379,7 @@ static BasicBlock *insertUniqueBackedgeBlock(Loop *L, BasicBlock *Preheader,
 
   // Figure out which basic blocks contain back-edges to the loop header.
   std::vector<BasicBlock*> BackedgeBlocks;
-  for (pred_iterator I = pred_begin(Header), E = pred_end(Header); I != E; ++I){
-    BasicBlock *P = *I;
-
+  for (BasicBlock *P : predecessors(Header)) {
     // Indirect edges cannot be split, so we must fail if we find one.
     if (P->getTerminator()->isIndirectTerminator())
       return nullptr;
@@ -505,12 +501,9 @@ ReprocessLoop:
     if (*BB == L->getHeader()) continue;
 
     SmallPtrSet<BasicBlock*, 4> BadPreds;
-    for (pred_iterator PI = pred_begin(*BB),
-         PE = pred_end(*BB); PI != PE; ++PI) {
-      BasicBlock *P = *PI;
+    for (BasicBlock *P : predecessors(*BB))
       if (!L->contains(P))
         BadPreds.insert(P);
-    }
 
     // Delete each unique out-of-loop (and thus dead) predecessor.
     for (BasicBlock *P : BadPreds) {
@@ -904,9 +897,8 @@ static void verifyLoop(Loop *L) {
   // Indirectbr can interfere with preheader and unique backedge insertion.
   if (!L->getLoopPreheader() || !L->getLoopLatch()) {
     bool HasIndBrPred = false;
-    for (pred_iterator PI = pred_begin(L->getHeader()),
-         PE = pred_end(L->getHeader()); PI != PE; ++PI)
-      if (isa<IndirectBrInst>((*PI)->getTerminator())) {
+    for (BasicBlock *Pred : predecessors(L->getHeader()))
+      if (isa<IndirectBrInst>(Pred->getTerminator())) {
         HasIndBrPred = true;
         break;
       }
diff --git a/llvm/lib/Transforms/Utils/MetaRenamer.cpp b/llvm/lib/Transforms/Utils/MetaRenamer.cpp
index e350320e7569..b1965cf2becb 100644
--- a/llvm/lib/Transforms/Utils/MetaRenamer.cpp
+++ b/llvm/lib/Transforms/Utils/MetaRenamer.cpp
@@ -67,9 +67,9 @@ struct Renamer {
 };
 
 void MetaRename(Function &F) {
-  for (auto AI = F.arg_begin(), AE = F.arg_end(); AI != AE; ++AI)
-    if (!AI->getType()->isVoidTy())
-      AI->setName("arg");
+  for (Argument &Arg : F.args())
+    if (!Arg.getType()->isVoidTy())
+      Arg.setName("arg");
 
   for (auto &BB : F) {
     BB.setName("bb");
@@ -101,12 +101,12 @@ void MetaRename(Module &M,
   }
 
   // Rename all global variables
-  for (auto GI = M.global_begin(), GE = M.global_end(); GI != GE; ++GI) {
-    StringRef Name = GI->getName();
+  for (GlobalVariable &GV : M.globals()) {
+    StringRef Name = GV.getName();
     if (Name.startswith("llvm.") || (!Name.empty() && Name[0] == 1))
       continue;
 
-    GI->setName("global");
+    GV.setName("global");
   }
 
   // Rename all struct types
diff --git a/llvm/lib/Transforms/Utils/SimplifyCFG.cpp b/llvm/lib/Transforms/Utils/SimplifyCFG.cpp
index b7184f25c183..df851c1b4a4c 100644
--- a/llvm/lib/Transforms/Utils/SimplifyCFG.cpp
+++ b/llvm/lib/Transforms/Utils/SimplifyCFG.cpp
@@ -2279,8 +2279,8 @@ bool SimplifyCFGOpt::SpeculativelyExecuteBB(BranchInst *BI, BasicBlock *ThenBB,
     // Do not hoist the instruction if any of its operands are defined but not
     // used in BB. The transformation will prevent the operand from
     // being sunk into the use block.
-    for (User::op_iterator i = I->op_begin(), e = I->op_end(); i != e; ++i) {
-      Instruction *OpI = dyn_cast<Instruction>(*i);
+    for (Use &Op : I->operands()) {
+      Instruction *OpI = dyn_cast<Instruction>(Op);
       if (!OpI || OpI->getParent() != BB || OpI->mayHaveSideEffects())
         continue; // Not a candidate for sinking.
 
@@ -2479,10 +2479,10 @@ static bool FoldCondBranchOnPHI(BranchInst *BI, DomTreeUpdater *DTU,
         N->setName(BBI->getName() + ".c");
 
       // Update operands due to translation.
-      for (User::op_iterator i = N->op_begin(), e = N->op_end(); i != e; ++i) {
-        DenseMap<Value *, Value *>::iterator PI = TranslateMap.find(*i);
+      for (Use &Op : N->operands()) {
+        DenseMap<Value *, Value *>::iterator PI = TranslateMap.find(Op);
         if (PI != TranslateMap.end())
-          *i = PI->second;
+          Op = PI->second;
       }
 
       // Check for trivial simplification.
@@ -3032,8 +3032,7 @@ bool llvm::FoldBranchToCommonDest(BranchInst *BI, DomTreeUpdater *DTU,
   if (is_contained(successors(BB), BB))
     return Changed;
 
-  for (pred_iterator PI = pred_begin(BB), E = pred_end(BB); PI != E; ++PI) {
-    BasicBlock *PredBlock = *PI;
+  for (BasicBlock *PredBlock : predecessors(BB)) {
     BranchInst *PBI = dyn_cast<BranchInst>(PredBlock->getTerminator());
 
     // Check that we have two conditional branches.  If there is a PHI node in
@@ -4410,8 +4409,7 @@ bool SimplifyCFGOpt::simplifyReturn(ReturnInst *RI, IRBuilder<> &Builder) {
   // Find predecessors that end with branches.
   SmallVector<BasicBlock *, 8> UncondBranchPreds;
   SmallVector<BranchInst *, 8> CondBranchPreds;
-  for (pred_iterator PI = pred_begin(BB), E = pred_end(BB); PI != E; ++PI) {
-    BasicBlock *P = *PI;
+  for (BasicBlock *P : predecessors(BB)) {
     Instruction *PTI = P->getTerminator();
     if (BranchInst *BI = dyn_cast<BranchInst>(PTI)) {
       if (BI->isUnconditional())
@@ -5641,8 +5639,7 @@ static void reuseTableCompare(
   // Although this check is invariant in the calling loops, it's better to do it
   // at this late stage. Practically we do it at most once for a switch.
   BasicBlock *BranchBlock = RangeCheckBranch->getParent();
-  for (auto PI = pred_begin(PhiBlock), E = pred_end(PhiBlock); PI != E; ++PI) {
-    BasicBlock *Pred = *PI;
+  for (BasicBlock *Pred : predecessors(PhiBlock)) {
     if (Pred != BranchBlock && Pred->getUniquePredecessor() != BranchBlock)
       return;
   }
@@ -6361,8 +6358,8 @@ bool SimplifyCFGOpt::simplifyCondBranch(BranchInst *BI, IRBuilder<> &Builder) {
         return requestResimplify();
 
   // Scan predecessor blocks for conditional branches.
-  for (pred_iterator PI = pred_begin(BB), E = pred_end(BB); PI != E; ++PI)
-    if (BranchInst *PBI = dyn_cast<BranchInst>((*PI)->getTerminator()))
+  for (BasicBlock *Pred : predecessors(BB))
+    if (BranchInst *PBI = dyn_cast<BranchInst>(Pred->getTerminator()))
       if (PBI != BI && PBI->isConditional())
         if (SimplifyCondBranchToCondBranch(PBI, BI, DTU, DL, TTI))
           return requestResimplify();