Forgot the dyn_cast_or_null intended for r277691.

llvm-svn: 277693
diff --git a/llvm/lib/Transforms/Utils/CloneFunction.cpp b/llvm/lib/Transforms/Utils/CloneFunction.cpp
index 4f00882..4f1052d 100644
--- a/llvm/lib/Transforms/Utils/CloneFunction.cpp
+++ b/llvm/lib/Transforms/Utils/CloneFunction.cpp
@@ -562,7 +562,7 @@
   // Note that we must test the size on each iteration, the worklist can grow.
   for (unsigned Idx = 0; Idx != Worklist.size(); ++Idx) {
     const Value *OrigV = Worklist[Idx];
-    auto *I = cast_or_null<Instruction>(VMap.lookup(OrigV));
+    auto *I = dyn_cast_or_null<Instruction>(VMap.lookup(OrigV));
     if (!I)
       continue;