Index: llvm/lib/Target/SystemZ/SystemZISelLowering.cpp
===================================================================
--- llvm/lib/Target/SystemZ/SystemZISelLowering.cpp
+++ llvm/lib/Target/SystemZ/SystemZISelLowering.cpp
@@ -6748,22 +6748,26 @@
     SDNode *N, DAGCombinerInfo &DCI) const {
   if (DCI.Level != BeforeLegalizeTypes)
     return SDValue();
+  SelectionDAG &DAG = DCI.DAG;
+  LLVMContext &Ctx = *DAG.getContext();
   unsigned Opcode = N->getOpcode();
   EVT OutVT = N->getValueType(0);
-  SelectionDAG &DAG = DCI.DAG;
+  Type *OutLLVMTy = OutVT.getTypeForEVT(Ctx);
   SDValue Op = N->getOperand(0);
-  unsigned OutScalarBits = OutVT.getScalarSizeInBits();
+  unsigned OutScalarBits = OutLLVMTy->getScalarSizeInBits();
   unsigned InScalarBits = Op->getValueType(0).getScalarSizeInBits();
 
   // Insert an extension before type-legalization to avoid scalarization, e.g.:
   // v2f64 = uint_to_fp v2i16
   // =>
   // v2f64 = uint_to_fp (v2i64 zero_extend v2i16)
-  if (OutVT.isVector() && OutScalarBits > InScalarBits) {
-    MVT ExtVT = MVT::getVectorVT(MVT::getIntegerVT(OutVT.getScalarSizeInBits()),
-                                 OutVT.getVectorNumElements());
+  if (OutLLVMTy->isVectorTy() && OutScalarBits > InScalarBits &&
+      OutScalarBits <= 64) {
+    unsigned NumElts = cast<FixedVectorType>(OutLLVMTy)->getNumElements();
+    EVT ExtVT = EVT::getVectorVT(
+        Ctx, EVT::getIntegerVT(Ctx, OutLLVMTy->getScalarSizeInBits()), NumElts);
     unsigned ExtOpcode =
-      (Opcode == ISD::UINT_TO_FP ? ISD::ZERO_EXTEND : ISD::SIGN_EXTEND);
+        (Opcode == ISD::UINT_TO_FP ? ISD::ZERO_EXTEND : ISD::SIGN_EXTEND);
     SDValue ExtOp = DAG.getNode(ExtOpcode, SDLoc(N), ExtVT, Op);
     return DAG.getNode(Opcode, SDLoc(N), OutVT, ExtOp);
   }
Index: llvm/test/CodeGen/SystemZ/vec-move-23.ll
===================================================================
--- llvm/test/CodeGen/SystemZ/vec-move-23.ll
+++ llvm/test/CodeGen/SystemZ/vec-move-23.ll
@@ -130,3 +130,36 @@
   ret void
 }
 
+; Test that this does not crash but results in scalarized conversions.
+define void @fun8(<2 x i64> %dwords, <2 x fp128> *%ptr) {
+; CHECK-LABEL: fun8
+; CHECK: vlgvg
+; CHECK: cxlgbr
+ %conv = uitofp <2 x i64> %dwords to <2 x fp128>
+ store <2 x fp128> %conv, <2 x fp128> *%ptr
+ ret void
+}
+
+; Test that this results in vectorized conversions.
+define void @fun9(<10 x i16> *%Src, <10 x float> *%ptr) {
+; CHECK-LABEL: fun9
+; Z15: 	    larl	%r1, .LCPI9_0
+; Z15-NEXT: vl	        %v0, 16(%r2), 4
+; Z15-NEXT: vl	        %v1, 0(%r2), 4
+; Z15-NEXT: vl	        %v2, 0(%r1), 3
+; Z15-NEXT: vperm	%v2, %v2, %v1, %v2
+; Z15-NEXT: vuplhh	%v1, %v1
+; Z15-NEXT: vuplhh	%v0, %v0
+; Z15-NEXT: vcelfb	%v2, %v2, 0, 0
+; Z15-NEXT: vcelfb	%v1, %v1, 0, 0
+; Z15-NEXT: vcelfb	%v0, %v0, 0, 0
+; Z15-NEXT: vsteg	%v0, 32(%r3), 0
+; Z15-NEXT: vst	%v2, 16(%r3), 4
+; Z15-NEXT: vst	%v1, 0(%r3), 4
+; Z15-NEXT: br	%r14
+
+ %Val = load <10 x i16>, <10 x i16> *%Src
+ %conv = uitofp <10 x i16> %Val to <10 x float>
+ store <10 x float> %conv, <10 x float> *%ptr
+ ret void
+}