Index: lib/Target/AArch64/AArch64TargetTransformInfo.cpp
===================================================================
--- lib/Target/AArch64/AArch64TargetTransformInfo.cpp
+++ lib/Target/AArch64/AArch64TargetTransformInfo.cpp
@@ -128,6 +128,9 @@
 
   unsigned getCostOfKeepingLiveOverCall(ArrayRef<Type*> Tys) const override;
 
+  void getUnrollingPreferences(Loop *L,
+                               UnrollingPreferences &UP) const override;
+
   /// @}
 };
 
@@ -521,3 +524,8 @@
     return 4;
   return 2;
 }
+
+void AArch64TTI::getUnrollingPreferences(Loop *L,
+                                         UnrollingPreferences &UP) const {
+    UP.Partial = UP.Runtime = true;
+}