DAG: Use poison for filler values on legalize error paths

Author: arsenm

llvm/lib/CodeGen/SelectionDAG/LegalizeDAG.cpp

@@ -2130,7 +2130,7 @@ SelectionDAGLegalize::ExpandLibCall(RTLIB::Libcall LC, SDNode *Node,
   if (const char *LibcallName = TLI.getLibcallName(LC))
     Callee = DAG.getExternalSymbol(LibcallName, CodePtrTy);
   else {
-    Callee = DAG.getUNDEF(CodePtrTy);
+    Callee = DAG.getPOISON(CodePtrTy);
     DAG.getContext()->emitError(Twine("no libcall available for ") +
                                 Node->getOperationName(&DAG));
   }
@@ -4992,7 +4992,7 @@ void SelectionDAGLegalize::ConvertNodeToLibcall(SDNode *Node) {
       // If the exponent does not match with sizeof(int) a libcall to
       // RTLIB::POWI would use the wrong type for the argument.
       DAG.getContext()->emitError("POWI exponent does not match sizeof(int)");
-      Results.push_back(DAG.getUNDEF(Node->getValueType(0)));
+      Results.push_back(DAG.getPOISON(Node->getValueType(0)));
       break;
     }
     ExpandFPLibCall(Node, LC, Results);