diff --git a/llvm/tools/llvm-stress/llvm-stress.cpp b/llvm/tools/llvm-stress/llvm-stress.cpp
--- a/llvm/tools/llvm-stress/llvm-stress.cpp
+++ b/llvm/tools/llvm-stress/llvm-stress.cpp
@@ -300,7 +300,7 @@
 
     if (len != (unsigned)-1)
       width = len;
-    return VectorType::get(Ty, width);
+    return FixedVectorType::get(Ty, width);
   }
 
   /// Pick a random scalar type.
@@ -628,9 +628,10 @@
 
     // If the value type is a vector, and we allow vector select, then in 50%
     // of the cases generate a vector select.
-    if (Val0->getType()->isVectorTy() && (getRandom() % 1)) {
-      unsigned NumElem = cast<VectorType>(Val0->getType())->getNumElements();
-      CondTy = VectorType::get(CondTy, NumElem);
+    if (isa<FixedVectorType>(Val0->getType()) && (getRandom() % 1)) {
+      unsigned NumElem =
+          cast<FixedVectorType>(Val0->getType())->getNumElements();
+      CondTy = FixedVectorType::get(CondTy, NumElem);
     }
 
     Value *Cond = getRandomValue(CondTy);