AMDGPU: Use poison instead of undef in more lowerings (#139208)

Author: arsenm

llvm/lib/Target/AMDGPU/AMDGPUISelLowering.cpp

@@ -1391,7 +1391,7 @@ SDValue AMDGPUTargetLowering::lowerUnhandledCall(CallLoweringInfo &CLI,
 
   if (!CLI.IsTailCall) {
     for (ISD::InputArg &Arg : CLI.Ins)
-      InVals.push_back(DAG.getUNDEF(Arg.VT));
+      InVals.push_back(DAG.getPOISON(Arg.VT));
   }
 
   return DAG.getEntryNode();
@@ -1537,7 +1537,7 @@ SDValue AMDGPUTargetLowering::LowerGlobalAddress(AMDGPUMachineFunction* MFI,
       SDValue OutputChain = DAG.getNode(ISD::TokenFactor, DL, MVT::Other,
                                         Trap, DAG.getRoot());
       DAG.setRoot(OutputChain);
-      return DAG.getUNDEF(Op.getValueType());
+      return DAG.getPOISON(Op.getValueType());
     }
 
     // XXX: What does the value of G->getOffset() mean?
@@ -1859,7 +1859,7 @@ SDValue AMDGPUTargetLowering::SplitVectorLoad(const SDValue Op,
     // This is the case that the vector is power of two so was evenly split.
     Join = DAG.getNode(ISD::CONCAT_VECTORS, SL, VT, LoLoad, HiLoad);
   } else {
-    Join = DAG.getNode(ISD::INSERT_SUBVECTOR, SL, VT, DAG.getUNDEF(VT), LoLoad,
+    Join = DAG.getNode(ISD::INSERT_SUBVECTOR, SL, VT, DAG.getPOISON(VT), LoLoad,
                        DAG.getVectorIdxConstant(0, SL));
     Join = DAG.getNode(
         HiVT.isVector() ? ISD::INSERT_SUBVECTOR : ISD::INSERT_VECTOR_ELT, SL,