use precise getters

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@63402 91177308-0d34-0410-b5e6-96231b3b80d8
diff --git a/lib/Transforms/Utils/Local.cpp b/lib/Transforms/Utils/Local.cpp
index b8077ae..c224853 100644
--- a/lib/Transforms/Utils/Local.cpp
+++ b/lib/Transforms/Utils/Local.cpp
@@ -38,8 +38,8 @@
   // Branch - See if we are conditional jumping on constant
   if (BranchInst *BI = dyn_cast<BranchInst>(T)) {
     if (BI->isUnconditional()) return false;  // Can't optimize uncond branch
-    BasicBlock *Dest1 = cast<BasicBlock>(BI->getOperand(0));
-    BasicBlock *Dest2 = cast<BasicBlock>(BI->getOperand(1));
+    BasicBlock *Dest1 = BI->getSuccessor(0);
+    BasicBlock *Dest2 = BI->getSuccessor(1);
 
     if (ConstantInt *Cond = dyn_cast<ConstantInt>(BI->getCondition())) {
       // Are we branching on constant?