[instCombine][bugfix] Fix crash caused by using of cast in instCombineSVECmpNE (#102472)

Author: cceerczw

llvm/lib/Target/AArch64/AArch64TargetTransformInfo.cpp

@@ -1187,7 +1187,8 @@ static std::optional<Instruction *> instCombineSVECmpNE(InstCombiner &IC,
     return std::nullopt;
 
   // Where the dupq is a lane 0 replicate of a vector insert
-  if (!cast<ConstantInt>(DupQLane->getArgOperand(1))->isZero())
+  auto *DupQLaneIdx = dyn_cast<ConstantInt>(DupQLane->getArgOperand(1));
+  if (!DupQLaneIdx || !DupQLaneIdx->isZero())
     return std::nullopt;
 
   auto *VecIns = dyn_cast<IntrinsicInst>(DupQLane->getArgOperand(0));