[SVE] Eliminate calls to default-false VectorType::get() from FuzzMutate

[ctetreau]

rebase

[ctetreau]

ping?

llvm/lib/FuzzMutate/Operations.cpp

static SourcePred validShuffleVectorIndex() {
   auto Pred = [](ArrayRef<Value *> Cur, const Value *V) {
     return ShuffleVectorInst::isValidOperands(Cur[0], Cur[1], V);
   };
   auto Make = [](ArrayRef<Value *> Cur, ArrayRef<Type *> Ts) {
     auto *FirstTy = cast<VectorType>(Cur[0]->getType());
     auto *Int32Ty = Type::getInt32Ty(Cur[0]->getContext());
     // TODO: It's straighforward to make up reasonable values, but listing them
     // exhaustively would be insane. Come up with a couple of sensible ones.
-    return std::vector<Constant *>{
-        UndefValue::get(VectorType::get(Int32Ty, FirstTy->getNumElements()))};
+    return std::vector<Constant *>{UndefValue::get(
+        FixedVectorType::get(Int32Ty, FirstTy->getNumElements()))};
   };
   return {Pred, Make};
 }
 
 OpDescriptor llvm::fuzzerop::shuffleVectorDescriptor(unsigned Weight) {
   auto buildShuffle = [](ArrayRef<Value *> Srcs, Instruction *Inst) {
     return new ShuffleVectorInst(Srcs[0], Srcs[1], Srcs[2], "S", Inst);
   };
   return {Weight,
           {anyVectorType(), matchFirstType(), validShuffleVectorIndex()},
           buildShuffle};
 }