[C++11] Add predecessors(BasicBlock *) / successors(BasicBlock *) iterator ranges.

Summary: This patch introduces two new iterator ranges and updates existing code to use it.  No functional change intended.

Test Plan: All tests (make check-all) still pass.

Reviewers: dblaikie

Reviewed By: dblaikie

Subscribers: llvm-commits

Differential Revision: http://reviews.llvm.org/D4481

llvm-svn: 213474
diff --git a/llvm/lib/Transforms/IPO/ArgumentPromotion.cpp b/llvm/lib/Transforms/IPO/ArgumentPromotion.cpp
index f9de54a..816fc29 100644
--- a/llvm/lib/Transforms/IPO/ArgumentPromotion.cpp
+++ b/llvm/lib/Transforms/IPO/ArgumentPromotion.cpp
@@ -473,8 +473,7 @@
     // Now check every path from the entry block to the load for transparency.
     // To do this, we perform a depth first search on the inverse CFG from the
     // loading block.
-    for (pred_iterator PI = pred_begin(BB), E = pred_end(BB); PI != E; ++PI) {
-      BasicBlock *P = *PI;
+    for (BasicBlock *P : predecessors(BB)) {
       for (idf_ext_iterator<BasicBlock*, SmallPtrSet<BasicBlock*, 16> >
              I = idf_ext_begin(P, TranspBlocks),
              E = idf_ext_end(P, TranspBlocks); I != E; ++I)
diff --git a/llvm/lib/Transforms/IPO/LoopExtractor.cpp b/llvm/lib/Transforms/IPO/LoopExtractor.cpp
index 20414aa..3f973c7 100644
--- a/llvm/lib/Transforms/IPO/LoopExtractor.cpp
+++ b/llvm/lib/Transforms/IPO/LoopExtractor.cpp
@@ -229,9 +229,7 @@
     // Look through the landing pad's predecessors. If one of them ends in an
     // 'invoke', then we want to split the landing pad.
     bool Split = false;
-    for (pred_iterator
-           PI = pred_begin(LPad), PE = pred_end(LPad); PI != PE; ++PI) {
-      BasicBlock *BB = *PI;
+    for (BasicBlock *BB : predecessors(LPad)) {
       if (BB->isLandingPad() && BB != Parent &&
           isa<InvokeInst>(Parent->getTerminator())) {
         Split = true;
diff --git a/llvm/lib/Transforms/IPO/PartialInlining.cpp b/llvm/lib/Transforms/IPO/PartialInlining.cpp
index 76d6dfa..5957e84 100644
--- a/llvm/lib/Transforms/IPO/PartialInlining.cpp
+++ b/llvm/lib/Transforms/IPO/PartialInlining.cpp
@@ -58,13 +58,12 @@
   BasicBlock* returnBlock = nullptr;
   BasicBlock* nonReturnBlock = nullptr;
   unsigned returnCount = 0;
-  for (succ_iterator SI = succ_begin(entryBlock), SE = succ_end(entryBlock);
-       SI != SE; ++SI)
-    if (isa<ReturnInst>((*SI)->getTerminator())) {
-      returnBlock = *SI;
+  for (BasicBlock *Succ : successors(entryBlock))
+    if (isa<ReturnInst>(Succ->getTerminator())) {
+      returnBlock = Succ;
       returnCount++;
     } else
-      nonReturnBlock = *SI;
+      nonReturnBlock = Succ;
   
   if (returnCount != 1)
     return nullptr;
diff --git a/llvm/lib/Transforms/InstCombine/InstructionCombining.cpp b/llvm/lib/Transforms/InstCombine/InstructionCombining.cpp
index d3648e2..0e85181 100644
--- a/llvm/lib/Transforms/InstCombine/InstructionCombining.cpp
+++ b/llvm/lib/Transforms/InstCombine/InstructionCombining.cpp
@@ -2718,8 +2718,8 @@
       if (UserParent != BB) {
         bool UserIsSuccessor = false;
         // See if the user is one of our successors.
-        for (succ_iterator SI = succ_begin(BB), E = succ_end(BB); SI != E; ++SI)
-          if (*SI == UserParent) {
+        for (BasicBlock *Succ : successors(BB))
+          if (Succ == UserParent) {
             UserIsSuccessor = true;
             break;
           }
diff --git a/llvm/lib/Transforms/Scalar/DeadStoreElimination.cpp b/llvm/lib/Transforms/Scalar/DeadStoreElimination.cpp
index 3af8ee7..51e0bc2 100644
--- a/llvm/lib/Transforms/Scalar/DeadStoreElimination.cpp
+++ b/llvm/lib/Transforms/Scalar/DeadStoreElimination.cpp
@@ -642,8 +642,7 @@
 /// them to F.
 static void FindUnconditionalPreds(SmallVectorImpl<BasicBlock *> &Blocks,
                                    BasicBlock *BB, DominatorTree *DT) {
-  for (pred_iterator I = pred_begin(BB), E = pred_end(BB); I != E; ++I) {
-    BasicBlock *Pred = *I;
+  for (BasicBlock *Pred : predecessors(BB)) {
     if (Pred == BB) continue;
     TerminatorInst *PredTI = Pred->getTerminator();
     if (PredTI->getNumSuccessors() != 1)
diff --git a/llvm/lib/Transforms/Scalar/GVN.cpp b/llvm/lib/Transforms/Scalar/GVN.cpp
index 106eba0..3ed7e3e 100644
--- a/llvm/lib/Transforms/Scalar/GVN.cpp
+++ b/llvm/lib/Transforms/Scalar/GVN.cpp
@@ -1555,9 +1555,7 @@
     FullyAvailableBlocks[UnavailableBlocks[i]] = false;
 
   SmallVector<BasicBlock *, 4> CriticalEdgePred;
-  for (pred_iterator PI = pred_begin(LoadBB), E = pred_end(LoadBB);
-       PI != E; ++PI) {
-    BasicBlock *Pred = *PI;
+  for (BasicBlock *Pred : predecessors(LoadBB)) {
     if (IsValueFullyAvailableInBlock(Pred, FullyAvailableBlocks, 0)) {
       continue;
     }
@@ -2483,9 +2481,7 @@
       BasicBlock *PREPred = nullptr;
       predMap.clear();
 
-      for (pred_iterator PI = pred_begin(CurrentBlock),
-           PE = pred_end(CurrentBlock); PI != PE; ++PI) {
-        BasicBlock *P = *PI;
+      for (BasicBlock *P : predecessors(CurrentBlock)) {
         // We're not interested in PRE where the block is its
         // own predecessor, or in blocks with predecessors
         // that are not reachable.
@@ -2713,14 +2709,13 @@
     for (SmallVectorImpl<BasicBlock *>::iterator I = Dom.begin(),
            E = Dom.end(); I != E; I++) {
       BasicBlock *B = *I;
-      for (succ_iterator SI = succ_begin(B), SE = succ_end(B); SI != SE; SI++) {
-        BasicBlock *S = *SI;
+      for (BasicBlock *S : successors(B)) {
         if (DeadBlocks.count(S))
           continue;
 
         bool AllPredDead = true;
-        for (pred_iterator PI = pred_begin(S), PE = pred_end(S); PI != PE; PI++)
-          if (!DeadBlocks.count(*PI)) {
+        for (BasicBlock *Pred : predecessors(S))
+          if (!DeadBlocks.count(Pred)) {
             AllPredDead = false;
             break;
           }
diff --git a/llvm/lib/Transforms/Scalar/JumpThreading.cpp b/llvm/lib/Transforms/Scalar/JumpThreading.cpp
index 21f8038..d9b6d56 100644
--- a/llvm/lib/Transforms/Scalar/JumpThreading.cpp
+++ b/llvm/lib/Transforms/Scalar/JumpThreading.cpp
@@ -353,8 +353,8 @@
 
   // If V is a constant, then it is known in all predecessors.
   if (Constant *KC = getKnownConstant(V, Preference)) {
-    for (pred_iterator PI = pred_begin(BB), E = pred_end(BB); PI != E; ++PI)
-      Result.push_back(std::make_pair(KC, *PI));
+    for (BasicBlock *Pred : predecessors(BB))
+      Result.push_back(std::make_pair(KC, Pred));
 
     return true;
   }
@@ -377,8 +377,7 @@
     // "X < 4" and "X < 3" is known true but "X < 4" itself is not available.
     // Perhaps getConstantOnEdge should be smart enough to do this?
 
-    for (pred_iterator PI = pred_begin(BB), E = pred_end(BB); PI != E; ++PI) {
-      BasicBlock *P = *PI;
+    for (BasicBlock *P : predecessors(BB)) {
       // If the value is known by LazyValueInfo to be a constant in a
       // predecessor, use that information to try to thread this block.
       Constant *PredCst = LVI->getConstantOnEdge(V, P, BB);
@@ -532,8 +531,7 @@
           cast<Instruction>(Cmp->getOperand(0))->getParent() != BB) {
         Constant *RHSCst = cast<Constant>(Cmp->getOperand(1));
 
-        for (pred_iterator PI = pred_begin(BB), E = pred_end(BB);PI != E; ++PI){
-          BasicBlock *P = *PI;
+        for (BasicBlock *P : predecessors(BB)) {
           // If the value is known by LazyValueInfo to be a constant in a
           // predecessor, use that information to try to thread this block.
           LazyValueInfo::Tristate Res =
@@ -606,8 +604,8 @@
   // If all else fails, see if LVI can figure out a constant value for us.
   Constant *CI = LVI->getConstant(V, BB);
   if (Constant *KC = getKnownConstant(CI, Preference)) {
-    for (pred_iterator PI = pred_begin(BB), E = pred_end(BB); PI != E; ++PI)
-      Result.push_back(std::make_pair(KC, *PI));
+    for (BasicBlock *Pred : predecessors(BB))
+      Result.push_back(std::make_pair(KC, Pred));
   }
 
   return !Result.empty();
@@ -899,10 +897,7 @@
 
   // If we got here, the loaded value is transparent through to the start of the
   // block.  Check to see if it is available in any of the predecessor blocks.
-  for (pred_iterator PI = pred_begin(LoadBB), PE = pred_end(LoadBB);
-       PI != PE; ++PI) {
-    BasicBlock *PredBB = *PI;
-
+  for (BasicBlock *PredBB : predecessors(LoadBB)) {
     // If we already scanned this predecessor, skip it.
     if (!PredsScanned.insert(PredBB))
       continue;
@@ -952,9 +947,7 @@
       AvailablePredSet.insert(AvailablePreds[i].first);
 
     // Add all the unavailable predecessors to the PredsToSplit list.
-    for (pred_iterator PI = pred_begin(LoadBB), PE = pred_end(LoadBB);
-         PI != PE; ++PI) {
-      BasicBlock *P = *PI;
+    for (BasicBlock *P : predecessors(LoadBB)) {
       // If the predecessor is an indirect goto, we can't split the edge.
       if (isa<IndirectBrInst>(P->getTerminator()))
         return false;
diff --git a/llvm/lib/Transforms/Scalar/LoopInstSimplify.cpp b/llvm/lib/Transforms/Scalar/LoopInstSimplify.cpp
index ab1a939..657038e 100644
--- a/llvm/lib/Transforms/Scalar/LoopInstSimplify.cpp
+++ b/llvm/lib/Transforms/Scalar/LoopInstSimplify.cpp
@@ -145,9 +145,7 @@
       // bodies of subloops. We visit the headers of loops so that we can process
       // their phis, but we contract the rest of the subloop body and only follow
       // edges leading back to the original loop.
-      for (succ_iterator SI = succ_begin(BB), SE = succ_end(BB); SI != SE;
-           ++SI) {
-        BasicBlock *SuccBB = *SI;
+      for (BasicBlock *SuccBB : successors(BB)) {
         if (!Visited.insert(SuccBB))
           continue;
 
diff --git a/llvm/lib/Transforms/Scalar/LoopUnswitch.cpp b/llvm/lib/Transforms/Scalar/LoopUnswitch.cpp
index 977c53a..68bd4b8 100644
--- a/llvm/lib/Transforms/Scalar/LoopUnswitch.cpp
+++ b/llvm/lib/Transforms/Scalar/LoopUnswitch.cpp
@@ -515,9 +515,9 @@
   }
 
   // Otherwise, this is an unvisited intra-loop node.  Check all successors.
-  for (succ_iterator SI = succ_begin(BB), E = succ_end(BB); SI != E; ++SI) {
+  for (BasicBlock *Succ : successors(BB)) {
     // Check to see if the successor is a trivial loop exit.
-    if (!isTrivialLoopExitBlockHelper(L, *SI, ExitBB, Visited))
+    if (!isTrivialLoopExitBlockHelper(L, Succ, ExitBB, Visited))
       return false;
   }
 
@@ -861,9 +861,7 @@
       PHINode *PN = PHINode::Create(LPad->getType(), 0, "",
                                     ExitSucc->getFirstInsertionPt());
 
-      for (pred_iterator I = pred_begin(ExitSucc), E = pred_end(ExitSucc);
-           I != E; ++I) {
-        BasicBlock *BB = *I;
+      for (BasicBlock *BB : predecessors(ExitSucc)) {
         LandingPadInst *LPI = BB->getLandingPadInst();
         LPI->replaceAllUsesWith(PN);
         PN->addIncoming(LPI, BB);
diff --git a/llvm/lib/Transforms/Scalar/SampleProfile.cpp b/llvm/lib/Transforms/Scalar/SampleProfile.cpp
index 73c97ff..8e3583a 100644
--- a/llvm/lib/Transforms/Scalar/SampleProfile.cpp
+++ b/llvm/lib/Transforms/Scalar/SampleProfile.cpp
@@ -865,8 +865,7 @@
     SmallPtrSet<BasicBlock *, 16> Visited;
     if (!Predecessors[B1].empty())
       llvm_unreachable("Found a stale predecessors list in a basic block.");
-    for (pred_iterator PI = pred_begin(B1), PE = pred_end(B1); PI != PE; ++PI) {
-      BasicBlock *B2 = *PI;
+    for (BasicBlock *B2 : predecessors(B1)) {
       if (Visited.insert(B2))
         Predecessors[B1].push_back(B2);
     }
@@ -875,8 +874,7 @@
     Visited.clear();
     if (!Successors[B1].empty())
       llvm_unreachable("Found a stale successors list in a basic block.");
-    for (succ_iterator SI = succ_begin(B1), SE = succ_end(B1); SI != SE; ++SI) {
-      BasicBlock *B2 = *SI;
+    for (BasicBlock *B2 : successors(B1)) {
       if (Visited.insert(B2))
         Successors[B1].push_back(B2);
     }
diff --git a/llvm/lib/Transforms/Scalar/Sink.cpp b/llvm/lib/Transforms/Scalar/Sink.cpp
index 7348c45..2f7a9f9 100644
--- a/llvm/lib/Transforms/Scalar/Sink.cpp
+++ b/llvm/lib/Transforms/Scalar/Sink.cpp
@@ -258,10 +258,11 @@
 
   // If no suitable postdominator was found, look at all the successors and
   // decide which one we should sink to, if any.
-  for (succ_iterator I = succ_begin(Inst->getParent()),
-      E = succ_end(Inst->getParent()); I != E && !SuccToSinkTo; ++I) {
-    if (IsAcceptableTarget(Inst, *I))
-      SuccToSinkTo = *I;
+  for (BasicBlock *Succ : successors(Inst->getParent())) {
+    if (SuccToSinkTo)
+      break;
+    if (IsAcceptableTarget(Inst, Succ))
+      SuccToSinkTo = Succ;
   }
 
   // If we couldn't find a block to sink to, ignore this instruction.
diff --git a/llvm/lib/Transforms/Scalar/StructurizeCFG.cpp b/llvm/lib/Transforms/Scalar/StructurizeCFG.cpp
index b9673ed..d2206e3 100644
--- a/llvm/lib/Transforms/Scalar/StructurizeCFG.cpp
+++ b/llvm/lib/Transforms/Scalar/StructurizeCFG.cpp
@@ -365,41 +365,39 @@
   BBPredicates &Pred = Predicates[BB];
   BBPredicates &LPred = LoopPreds[BB];
 
-  for (pred_iterator PI = pred_begin(BB), PE = pred_end(BB);
-       PI != PE; ++PI) {
-
+  for (BasicBlock *Predecessor : predecessors(BB)) {
     // Ignore it if it's a branch from outside into our region entry
-    if (!ParentRegion->contains(*PI))
+    if (!ParentRegion->contains(Predecessor))
       continue;
 
-    Region *R = RI->getRegionFor(*PI);
+    Region *R = RI->getRegionFor(Predecessor);
     if (R == ParentRegion) {
 
       // It's a top level block in our region
-      BranchInst *Term = cast<BranchInst>((*PI)->getTerminator());
+      BranchInst *Term = cast<BranchInst>(Predecessor->getTerminator());
       for (unsigned i = 0, e = Term->getNumSuccessors(); i != e; ++i) {
         BasicBlock *Succ = Term->getSuccessor(i);
         if (Succ != BB)
           continue;
 
-        if (Visited.count(*PI)) {
+        if (Visited.count(Predecessor)) {
           // Normal forward edge
           if (Term->isConditional()) {
             // Try to treat it like an ELSE block
             BasicBlock *Other = Term->getSuccessor(!i);
             if (Visited.count(Other) && !Loops.count(Other) &&
-                !Pred.count(Other) && !Pred.count(*PI)) {
+                !Pred.count(Other) && !Pred.count(Predecessor)) {
 
               Pred[Other] = BoolFalse;
-              Pred[*PI] = BoolTrue;
+              Pred[Predecessor] = BoolTrue;
               continue;
             }
           }
-          Pred[*PI] = buildCondition(Term, i, false);
+          Pred[Predecessor] = buildCondition(Term, i, false);
 
         } else {
           // Back edge
-          LPred[*PI] = buildCondition(Term, i, true);
+          LPred[Predecessor] = buildCondition(Term, i, true);
         }
       }
 
@@ -574,11 +572,8 @@
   if (!Term)
     return;
 
-  for (succ_iterator SI = succ_begin(BB), SE = succ_end(BB);
-       SI != SE; ++SI) {
-
-    delPhiValues(BB, *SI);
-  }
+  for (BasicBlock *Succ : successors(BB))
+    delPhiValues(BB, Succ);
 
   Term->eraseFromParent();
 }
@@ -592,10 +587,7 @@
     BasicBlock *Dominator = nullptr;
 
     // Find all the edges from the sub region to the exit
-    for (pred_iterator I = pred_begin(OldExit), E = pred_end(OldExit);
-         I != E;) {
-
-      BasicBlock *BB = *I++;
+    for (BasicBlock *BB : predecessors(OldExit)) {
       if (!SubRegion->contains(BB))
         continue;
 
diff --git a/llvm/lib/Transforms/Scalar/TailRecursionElimination.cpp b/llvm/lib/Transforms/Scalar/TailRecursionElimination.cpp
index 05b9892..d9280ac6 100644
--- a/llvm/lib/Transforms/Scalar/TailRecursionElimination.cpp
+++ b/llvm/lib/Transforms/Scalar/TailRecursionElimination.cpp
@@ -335,7 +335,7 @@
       }
     }
 
-    for (auto *SuccBB : make_range(succ_begin(BB), succ_end(BB))) {
+    for (auto *SuccBB : successors(BB)) {
       auto &State = Visited[SuccBB];
       if (State < Escaped) {
         State = Escaped;
@@ -807,8 +807,7 @@
   // predecessors and perform TRC there. Look for predecessors that end
   // in unconditional branch and recursive call(s).
   SmallVector<BranchInst*, 8> UncondBranchPreds;
-  for (pred_iterator PI = pred_begin(BB), E = pred_end(BB); PI != E; ++PI) {
-    BasicBlock *Pred = *PI;
+  for (BasicBlock *Pred : predecessors(BB)) {
     TerminatorInst *PTI = Pred->getTerminator();
     if (BranchInst *BI = dyn_cast<BranchInst>(PTI))
       if (BI->isUnconditional())
diff --git a/llvm/lib/Transforms/Utils/BasicBlockUtils.cpp b/llvm/lib/Transforms/Utils/BasicBlockUtils.cpp
index 602e8ba..5af417c 100644
--- a/llvm/lib/Transforms/Utils/BasicBlockUtils.cpp
+++ b/llvm/lib/Transforms/Utils/BasicBlockUtils.cpp
@@ -549,14 +549,11 @@
 
   // Move the remaining edges from OrigBB to point to NewBB2.
   SmallVector<BasicBlock*, 8> NewBB2Preds;
-  for (pred_iterator i = pred_begin(OrigBB), e = pred_end(OrigBB);
-       i != e; ) {
-    BasicBlock *Pred = *i++;
+  for (BasicBlock *Pred : predecessors(OrigBB)) {
     if (Pred == NewBB1) continue;
     assert(!isa<IndirectBrInst>(Pred->getTerminator()) &&
            "Cannot split an edge from an IndirectBrInst");
     NewBB2Preds.push_back(Pred);
-    e = pred_end(OrigBB);
   }
 
   BasicBlock *NewBB2 = nullptr;
diff --git a/llvm/lib/Transforms/Utils/BreakCriticalEdges.cpp b/llvm/lib/Transforms/Utils/BreakCriticalEdges.cpp
index 80bd516..dc12f97 100644
--- a/llvm/lib/Transforms/Utils/BreakCriticalEdges.cpp
+++ b/llvm/lib/Transforms/Utils/BreakCriticalEdges.cpp
@@ -233,9 +233,7 @@
       if (PN->getIncomingBlock(i) != NewBB)
         OtherPreds.push_back(PN->getIncomingBlock(i));
   } else {
-    for (pred_iterator I = pred_begin(DestBB), E = pred_end(DestBB);
-         I != E; ++I) {
-      BasicBlock *P = *I;
+    for (BasicBlock *P : predecessors(DestBB)) {
       if (P != NewBB)
         OtherPreds.push_back(P);
     }
@@ -321,9 +319,7 @@
         // the predecessor must be directly in TIL, not in a subloop, or again
         // LoopSimplify doesn't hold.
         SmallVector<BasicBlock *, 4> LoopPreds;
-        for (pred_iterator I = pred_begin(DestBB), E = pred_end(DestBB); I != E;
-             ++I) {
-          BasicBlock *P = *I;
+        for (BasicBlock *P : predecessors(DestBB)) {
           if (P == NewBB)
             continue; // The new block is known.
           if (LI->getLoopFor(P) != TIL) {
diff --git a/llvm/lib/Transforms/Utils/CloneFunction.cpp b/llvm/lib/Transforms/Utils/CloneFunction.cpp
index 5c8f20d..f148ea1 100644
--- a/llvm/lib/Transforms/Utils/CloneFunction.cpp
+++ b/llvm/lib/Transforms/Utils/CloneFunction.cpp
@@ -514,9 +514,8 @@
       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/CodeExtractor.cpp b/llvm/lib/Transforms/Utils/CodeExtractor.cpp
index e70a7d6..d7445ef 100644
--- a/llvm/lib/Transforms/Utils/CodeExtractor.cpp
+++ b/llvm/lib/Transforms/Utils/CodeExtractor.cpp
@@ -91,9 +91,8 @@
   for (SetVector<BasicBlock *>::iterator I = std::next(Result.begin()),
                                          E = Result.end();
        I != E; ++I)
-    for (pred_iterator PI = pred_begin(*I), PE = pred_end(*I);
-         PI != PE; ++PI)
-      assert(Result.count(*PI) &&
+    for (BasicBlock *Pred : predecessors(*I))
+      assert(Result.count(Pred) &&
              "No blocks in this region may have entries from outside the region"
              " except for the first block!");
 #endif
@@ -721,9 +720,9 @@
   SmallPtrSet<BasicBlock *, 1> ExitBlocks;
   for (SetVector<BasicBlock *>::iterator I = Blocks.begin(), E = Blocks.end();
        I != E; ++I)
-    for (succ_iterator SI = succ_begin(*I), SE = succ_end(*I); SI != SE; ++SI)
-      if (!Blocks.count(*SI))
-        ExitBlocks.insert(*SI);
+    for (BasicBlock *Succ : successors(*I))
+      if (!Blocks.count(Succ))
+        ExitBlocks.insert(Succ);
   NumExitBlocks = ExitBlocks.size();
 
   // Construct new function based on inputs/outputs & add allocas for all defs.
diff --git a/llvm/lib/Transforms/Utils/Local.cpp b/llvm/lib/Transforms/Utils/Local.cpp
index a5e443f..113a2ae 100644
--- a/llvm/lib/Transforms/Utils/Local.cpp
+++ b/llvm/lib/Transforms/Utils/Local.cpp
@@ -1129,8 +1129,8 @@
   BasicBlock *BB = I->getParent();
   // Loop over all of the successors, removing BB's entry from any PHI
   // nodes.
-  for (succ_iterator SI = succ_begin(BB), SE = succ_end(BB); SI != SE; ++SI)
-    (*SI)->removePredecessor(BB);
+  for (BasicBlock *Succ : successors(BB))
+    Succ->removePredecessor(BB);
 
   // Insert a call to llvm.trap right before this.  This turns the undefined
   // behavior into a hard fail instead of falling through into random code.
@@ -1236,9 +1236,9 @@
     }
 
     Changed |= ConstantFoldTerminator(BB, true);
-    for (succ_iterator SI = succ_begin(BB), SE = succ_end(BB); SI != SE; ++SI)
-      if (Reachable.insert(*SI))
-        Worklist.push_back(*SI);
+    for (BasicBlock *Succ : successors(BB))
+      if (Reachable.insert(Succ))
+        Worklist.push_back(Succ);
   } while (!Worklist.empty());
   return Changed;
 }
@@ -1263,9 +1263,9 @@
     if (Reachable.count(BB))
       continue;
 
-    for (succ_iterator SI = succ_begin(BB), SE = succ_end(BB); SI != SE; ++SI)
-      if (Reachable.count(*SI))
-        (*SI)->removePredecessor(BB);
+    for (BasicBlock *Succ : successors(BB))
+      if (Reachable.count(Succ))
+        Succ->removePredecessor(BB);
     BB->dropAllReferences();
   }
 
diff --git a/llvm/lib/Transforms/Utils/LoopSimplify.cpp b/llvm/lib/Transforms/Utils/LoopSimplify.cpp
index ef42291..faab772 100644
--- a/llvm/lib/Transforms/Utils/LoopSimplify.cpp
+++ b/llvm/lib/Transforms/Utils/LoopSimplify.cpp
@@ -114,9 +114,7 @@
 
   // 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 branch, we won't
       // be able to fully transform the loop, because it prohibits
@@ -158,8 +156,7 @@
 /// the loop.
 static BasicBlock *rewriteLoopExitBlock(Loop *L, BasicBlock *Exit, Pass *PP) {
   SmallVector<BasicBlock*, 8> LoopBlocks;
-  for (pred_iterator I = pred_begin(Exit), E = pred_end(Exit); I != E; ++I) {
-    BasicBlock *P = *I;
+  for (BasicBlock *P : predecessors(Exit)) {
     if (L->contains(P)) {
       // Don't do this if the loop is exited via an indirect branch.
       if (isa<IndirectBrInst>(P->getTerminator())) return nullptr;
@@ -199,10 +196,8 @@
     if (Blocks.insert(BB).second && BB != StopBlock)
       // If BB is not already processed and it is not a stop block then
       // insert its predecessor in the work list
-      for (pred_iterator I = pred_begin(BB), E = pred_end(BB); I != E; ++I) {
-        BasicBlock *WBB = *I;
+      for (BasicBlock *WBB : predecessors(BB))
         Worklist.push_back(WBB);
-      }
   } while (!Worklist.empty());
 }
 
@@ -316,8 +311,7 @@
   // Determine which blocks should stay in L and which should be moved out to
   // the Outer loop now.
   std::set<BasicBlock*> BlocksInL;
-  for (pred_iterator PI=pred_begin(Header), E = pred_end(Header); PI!=E; ++PI) {
-    BasicBlock *P = *PI;
+  for (BasicBlock *P : predecessors(Header)) {
     if (DT->dominates(Header, P))
       addBlockAndPredsToSet(P, Header, BlocksInL);
   }
@@ -371,9 +365,7 @@
 
   // 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)) {
     // Indirectbr edges cannot be split, so we must fail if we find one.
     if (isa<IndirectBrInst>(P->getTerminator()))
       return nullptr;
@@ -488,9 +480,7 @@
     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);
     }
@@ -503,8 +493,8 @@
                    << (*I)->getName() << "\n");
 
       // Inform each successor of each dead pred.
-      for (succ_iterator SI = succ_begin(*I), SE = succ_end(*I); SI != SE; ++SI)
-        (*SI)->removePredecessor(*I);
+      for (BasicBlock *Succ : successors(*I))
+        Succ->removePredecessor(*I);
       // Zap the dead pred's terminator and replace it with unreachable.
       TerminatorInst *TI = (*I)->getTerminator();
        TI->replaceAllUsesWith(UndefValue::get(TI->getType()));
@@ -561,11 +551,10 @@
   for (SmallSetVector<BasicBlock *, 8>::iterator I = ExitBlockSet.begin(),
          E = ExitBlockSet.end(); I != E; ++I) {
     BasicBlock *ExitBlock = *I;
-    for (pred_iterator PI = pred_begin(ExitBlock), PE = pred_end(ExitBlock);
-         PI != PE; ++PI)
+    for (BasicBlock *Pred : predecessors(ExitBlock))
       // Must be exactly this loop: no subloops, parent loops, or non-loop preds
       // allowed.
-      if (!L->contains(*PI)) {
+      if (!L->contains(Pred)) {
         if (rewriteLoopExitBlock(L, ExitBlock, PP)) {
           ++NumInserted;
           Changed = true;
diff --git a/llvm/lib/Transforms/Utils/LoopUnroll.cpp b/llvm/lib/Transforms/Utils/LoopUnroll.cpp
index ab1c25a..3b0e813 100644
--- a/llvm/lib/Transforms/Utils/LoopUnroll.cpp
+++ b/llvm/lib/Transforms/Utils/LoopUnroll.cpp
@@ -328,11 +328,10 @@
       L->addBasicBlockToLoop(New, LI->getBase());
 
       // Add phi entries for newly created values to all exit blocks.
-      for (succ_iterator SI = succ_begin(*BB), SE = succ_end(*BB);
-           SI != SE; ++SI) {
-        if (L->contains(*SI))
+      for (BasicBlock *Succ : successors(*BB)) {
+        if (L->contains(Succ))
           continue;
-        for (BasicBlock::iterator BBI = (*SI)->begin();
+        for (BasicBlock::iterator BBI = Succ->begin();
              PHINode *phi = dyn_cast<PHINode>(BBI); ++BBI) {
           Value *Incoming = phi->getIncomingValueForBlock(*BB);
           ValueToValueMapTy::iterator It = LastValueMap.find(Incoming);
@@ -414,11 +413,10 @@
       // Remove phi operands at this loop exit
       if (Dest != LoopExit) {
         BasicBlock *BB = Latches[i];
-        for (succ_iterator SI = succ_begin(BB), SE = succ_end(BB);
-             SI != SE; ++SI) {
-          if (*SI == Headers[i])
+        for (BasicBlock *Succ : successors(BB)) {
+          if (Succ == Headers[i])
             continue;
-          for (BasicBlock::iterator BBI = (*SI)->begin();
+          for (BasicBlock::iterator BBI = Succ->begin();
                PHINode *Phi = dyn_cast<PHINode>(BBI); ++BBI) {
             Phi->removeIncomingValue(BB, false);
           }
diff --git a/llvm/lib/Transforms/Utils/LoopUnrollRuntime.cpp b/llvm/lib/Transforms/Utils/LoopUnrollRuntime.cpp
index a96c46a..ce420ee 100644
--- a/llvm/lib/Transforms/Utils/LoopUnrollRuntime.cpp
+++ b/llvm/lib/Transforms/Utils/LoopUnrollRuntime.cpp
@@ -66,9 +66,8 @@
   // The new PHI node is inserted in the prolog end basic block.
   // The new PHI name is added as an operand of a PHI node in either
   // the loop header or the loop exit block.
-  for (succ_iterator SBI = succ_begin(Latch), SBE = succ_end(Latch);
-       SBI != SBE; ++SBI) {
-    for (BasicBlock::iterator BBI = (*SBI)->begin();
+  for (BasicBlock *Succ : successors(Latch)) {
+    for (BasicBlock::iterator BBI = Succ->begin();
          PHINode *PN = dyn_cast<PHINode>(BBI); ++BBI) {
 
       // Add a new PHI node to the prolog end block and add the
diff --git a/llvm/lib/Transforms/Utils/PromoteMemoryToRegister.cpp b/llvm/lib/Transforms/Utils/PromoteMemoryToRegister.cpp
index 06d73fe..a3da989 100644
--- a/llvm/lib/Transforms/Utils/PromoteMemoryToRegister.cpp
+++ b/llvm/lib/Transforms/Utils/PromoteMemoryToRegister.cpp
@@ -822,9 +822,7 @@
     // Since the value is live into BB, it is either defined in a predecessor or
     // live into it to.  Add the preds to the worklist unless they are a
     // defining block.
-    for (pred_iterator PI = pred_begin(BB), E = pred_end(BB); PI != E; ++PI) {
-      BasicBlock *P = *PI;
-
+    for (BasicBlock *P : predecessors(BB)) {
       // The value is not live into a predecessor if it defines the value.
       if (DefBlocks.count(P))
         continue;
@@ -885,9 +883,8 @@
       DomTreeNode *Node = Worklist.pop_back_val();
       BasicBlock *BB = Node->getBlock();
 
-      for (succ_iterator SI = succ_begin(BB), SE = succ_end(BB); SI != SE;
-           ++SI) {
-        DomTreeNode *SuccNode = DT.getNode(*SI);
+      for (BasicBlock *Succ : successors(BB)) {
+        DomTreeNode *SuccNode = DT.getNode(Succ);
 
         // Quickly skip all CFG edges that are also dominator tree edges instead
         // of catching them below.
diff --git a/llvm/lib/Transforms/Utils/SSAUpdater.cpp b/llvm/lib/Transforms/Utils/SSAUpdater.cpp
index 3fcb789..67d06d1 100644
--- a/llvm/lib/Transforms/Utils/SSAUpdater.cpp
+++ b/llvm/lib/Transforms/Utils/SSAUpdater.cpp
@@ -110,8 +110,7 @@
     }
   } else {
     bool isFirstPred = true;
-    for (pred_iterator PI = pred_begin(BB), E = pred_end(BB); PI != E; ++PI) {
-      BasicBlock *PredBB = *PI;
+    for (BasicBlock *PredBB : predecessors(BB)) {
       Value *PredVal = GetValueAtEndOfBlock(PredBB);
       PredValues.push_back(std::make_pair(PredBB, PredVal));
 
@@ -248,8 +247,7 @@
       for (unsigned PI = 0, E = SomePhi->getNumIncomingValues(); PI != E; ++PI)
         Preds->push_back(SomePhi->getIncomingBlock(PI));
     } else {
-      for (pred_iterator PI = pred_begin(BB), E = pred_end(BB); PI != E; ++PI)
-        Preds->push_back(*PI);
+      Preds->insert(Preds->end(), pred_begin(BB), pred_end(BB));
     }
   }
 
diff --git a/llvm/lib/Transforms/Utils/SimplifyCFG.cpp b/llvm/lib/Transforms/Utils/SimplifyCFG.cpp
index 960b198..4e589cc 100644
--- a/llvm/lib/Transforms/Utils/SimplifyCFG.cpp
+++ b/llvm/lib/Transforms/Utils/SimplifyCFG.cpp
@@ -130,9 +130,9 @@
   BasicBlock *SI2BB = SI2->getParent();
   SmallPtrSet<BasicBlock*, 16> SI1Succs(succ_begin(SI1BB), succ_end(SI1BB));
 
-  for (succ_iterator I = succ_begin(SI2BB), E = succ_end(SI2BB); I != E; ++I)
-    if (SI1Succs.count(*I))
-      for (BasicBlock::iterator BBI = (*I)->begin();
+  for (BasicBlock *Succ : successors(SI2BB))
+    if (SI1Succs.count(Succ))
+      for (BasicBlock::iterator BBI = Succ->begin();
            isa<PHINode>(BBI); ++BBI) {
         PHINode *PN = cast<PHINode>(BBI);
         if (PN->getIncomingValueForBlock(SI1BB) !=
@@ -171,9 +171,9 @@
   BasicBlock *SI1BB = SI1->getParent();
   BasicBlock *SI2BB = SI2->getParent();
   SmallPtrSet<BasicBlock*, 16> SI1Succs(succ_begin(SI1BB), succ_end(SI1BB));
-  for (succ_iterator I = succ_begin(SI2BB), E = succ_end(SI2BB); I != E; ++I)
-    if (SI1Succs.count(*I))
-      for (BasicBlock::iterator BBI = (*I)->begin();
+  for (BasicBlock *Succ : successors(SI2BB))
+    if (SI1Succs.count(Succ))
+      for (BasicBlock::iterator BBI = Succ->begin();
            isa<PHINode>(BBI); ++BBI) {
         PHINode *PN = cast<PHINode>(BBI);
         if (PN->getIncomingValueForBlock(SI1BB) != Cond ||
@@ -683,9 +683,9 @@
 
   // Remove PHI node entries for dead edges.
   BasicBlock *CheckEdge = TheRealDest;
-  for (succ_iterator SI = succ_begin(TIBB), e = succ_end(TIBB); SI != e; ++SI)
-    if (*SI != CheckEdge)
-      (*SI)->removePredecessor(TIBB);
+  for (BasicBlock *Succ : successors(TIBB))
+    if (Succ != CheckEdge)
+      Succ->removePredecessor(TIBB);
     else
       CheckEdge = nullptr;
 
@@ -981,9 +981,9 @@
 // to put the select in this case.
 static bool isSafeToHoistInvoke(BasicBlock *BB1, BasicBlock *BB2,
                                 Instruction *I1, Instruction *I2) {
-  for (succ_iterator SI = succ_begin(BB1), E = succ_end(BB1); SI != E; ++SI) {
+  for (BasicBlock *Succ : successors(BB1)) {
     PHINode *PN;
-    for (BasicBlock::iterator BBI = SI->begin();
+    for (BasicBlock::iterator BBI = Succ->begin();
          (PN = dyn_cast<PHINode>(BBI)); ++BBI) {
       Value *BB1V = PN->getIncomingValueForBlock(BB1);
       Value *BB2V = PN->getIncomingValueForBlock(BB2);
@@ -1063,9 +1063,9 @@
   if (isa<InvokeInst>(I1) && !isSafeToHoistInvoke(BB1, BB2, I1, I2))
     return Changed;
 
-  for (succ_iterator SI = succ_begin(BB1), E = succ_end(BB1); SI != E; ++SI) {
+  for (BasicBlock *Succ : successors(BB1)) {
     PHINode *PN;
-    for (BasicBlock::iterator BBI = SI->begin();
+    for (BasicBlock::iterator BBI = Succ->begin();
          (PN = dyn_cast<PHINode>(BBI)); ++BBI) {
       Value *BB1V = PN->getIncomingValueForBlock(BB1);
       Value *BB2V = PN->getIncomingValueForBlock(BB2);
@@ -1094,9 +1094,9 @@
   // them.  If they do, all PHI entries for BB1/BB2 must agree for all PHI
   // nodes, so we insert select instruction to compute the final result.
   std::map<std::pair<Value*,Value*>, SelectInst*> InsertedSelects;
-  for (succ_iterator SI = succ_begin(BB1), E = succ_end(BB1); SI != E; ++SI) {
+  for (BasicBlock *Succ : successors(BB1)) {
     PHINode *PN;
-    for (BasicBlock::iterator BBI = SI->begin();
+    for (BasicBlock::iterator BBI = Succ->begin();
          (PN = dyn_cast<PHINode>(BBI)); ++BBI) {
       Value *BB1V = PN->getIncomingValueForBlock(BB1);
       Value *BB2V = PN->getIncomingValueForBlock(BB2);
@@ -1118,8 +1118,8 @@
   }
 
   // Update any PHI nodes in our new successors.
-  for (succ_iterator SI = succ_begin(BB1), E = succ_end(BB1); SI != E; ++SI)
-    AddPredecessorToBlock(*SI, BIParent, BB1);
+  for (BasicBlock *Succ : successors(BB1))
+    AddPredecessorToBlock(Succ, BIParent, BB1);
 
   EraseTerminatorInstAndDCECond(BI);
   return true;
@@ -2051,8 +2051,7 @@
   if (TrueDest == BB || FalseDest == BB)
     return false;
 
-  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
@@ -2885,8 +2884,8 @@
   // Turn all invokes that unwind here into calls and delete the basic block.
   bool InvokeRequiresTableEntry = false;
   bool Changed = false;
-  for (pred_iterator PI = pred_begin(BB), PE = pred_end(BB); PI != PE;) {
-    InvokeInst *II = cast<InvokeInst>((*PI++)->getTerminator());
+  for (BasicBlock *Pred : predecessors(BB)) {
+    InvokeInst *II = cast<InvokeInst>(Pred->getTerminator());
 
     if (II->hasFnAttr(Attribute::UWTable)) {
       // Don't remove an `invoke' instruction if the ABI requires an entry into
@@ -2933,8 +2932,7 @@
   // 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)) {
     TerminatorInst *PTI = P->getTerminator();
     if (BranchInst *BI = dyn_cast<BranchInst>(PTI)) {
       if (BI->isUnconditional())
@@ -4100,8 +4098,8 @@
         return SimplifyCFG(BB, TTI, DL) | true;
 
   // 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))
           return SimplifyCFG(BB, TTI, DL) | true;
diff --git a/llvm/lib/Transforms/Vectorize/LoopVectorize.cpp b/llvm/lib/Transforms/Vectorize/LoopVectorize.cpp
index 909de67..adf241d 100644
--- a/llvm/lib/Transforms/Vectorize/LoopVectorize.cpp
+++ b/llvm/lib/Transforms/Vectorize/LoopVectorize.cpp
@@ -2934,9 +2934,8 @@
   Value *Zero = ConstantInt::get(IntegerType::getInt1Ty(BB->getContext()), 0);
   VectorParts BlockMask = getVectorValue(Zero);
 
-  // For each pred:
-  for (pred_iterator it = pred_begin(BB), e = pred_end(BB); it != e; ++it) {
-    VectorParts EM = createEdgeMask(*it, BB);
+  for (BasicBlock *Pred : predecessors(BB)) {
+    VectorParts EM = createEdgeMask(Pred, BB);
     for (unsigned part = 0; part < UF; ++part)
       BlockMask[part] = Builder.CreateOr(BlockMask[part], EM[part]);
   }