Index: llvm/lib/Transforms/Vectorize/LoopVectorize.cpp
===================================================================
--- llvm/lib/Transforms/Vectorize/LoopVectorize.cpp
+++ llvm/lib/Transforms/Vectorize/LoopVectorize.cpp
@@ -3272,8 +3272,10 @@
   // execute VF scalar calls, and then gather the result into the vector return
   // value.
   unsigned ScalarCallCost = TTI.getCallInstrCost(F, ScalarRetTy, ScalarTys);
-  if (VF == 1)
+  if (VF == 1) {
+    NeedToScalarize = true;
     return ScalarCallCost;
+  }
 
   // Compute corresponding vector type for return value and arguments.
   Type *RetTy = ToVectorTy(ScalarRetTy, VF);