diff --git a/llvm/lib/IR/BasicBlock.cpp b/llvm/lib/IR/BasicBlock.cpp
index 2251392..938c401 100644
--- a/llvm/lib/IR/BasicBlock.cpp
+++ b/llvm/lib/IR/BasicBlock.cpp
@@ -264,7 +264,8 @@
 }
 
 iterator_range<BasicBlock::phi_iterator> BasicBlock::phis() {
-  return make_range<phi_iterator>(dyn_cast<PHINode>(&front()), nullptr);
+  PHINode *P = empty() ? nullptr : dyn_cast<PHINode>(&*begin());
+  return make_range<phi_iterator>(P, nullptr);
 }
 
 /// This method is used to notify a BasicBlock that the