[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

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@213474 91177308-0d34-0410-b5e6-96231b3b80d8

lib/Transforms/Utils/CloneFunction.cpp

@@ -514,9 +514,8 @@ void llvm::CloneAndPruneFunctionInto(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)