Index: llvm/lib/Transforms/InstCombine/InstCombineCasts.cpp
===================================================================
--- llvm/lib/Transforms/InstCombine/InstCombineCasts.cpp
+++ llvm/lib/Transforms/InstCombine/InstCombineCasts.cpp
@@ -2528,7 +2528,8 @@
 
   if (VectorType *DestVTy = dyn_cast<VectorType>(DestTy)) {
     // Beware: messing with this target-specific oddity may cause trouble.
-    if (DestVTy->getNumElements() == 1 && SrcTy->isX86_MMXTy()) {
+    if (isa<FixedVectorType>(DestVTy) && DestVTy->getNumElements() == 1 &&
+        SrcTy->isX86_MMXTy()) {
       Value *Elem = Builder.CreateBitCast(Src, DestVTy->getElementType());
       return InsertElementInst::Create(UndefValue::get(DestTy), Elem,
                      Constant::getNullValue(Type::getInt32Ty(CI.getContext())));
@@ -2555,7 +2556,7 @@
     }
   }
 
-  if (VectorType *SrcVTy = dyn_cast<VectorType>(SrcTy)) {
+  if (FixedVectorType *SrcVTy = dyn_cast<FixedVectorType>(SrcTy)) {
     if (SrcVTy->getNumElements() == 1) {
       // If our destination is not a vector, then make this a straight
       // scalar-scalar cast.