diff --git a/llvm/include/llvm/ADT/PointerIntPair.h b/llvm/include/llvm/ADT/PointerIntPair.h
--- a/llvm/include/llvm/ADT/PointerIntPair.h
+++ b/llvm/include/llvm/ADT/PointerIntPair.h
@@ -53,7 +53,7 @@
   const Ptr *getPointerAddress() const { return reinterpret_cast<Ptr *>(Data); }
 
 private:
-  alignas(Ptr) unsigned char Data[sizeof(Ptr)];
+  alignas(Ptr) unsigned char Data[sizeof(Ptr)] = {};
 };
 } // namespace detail