From f122995d1450aa8156197a82b7c150ab5364383b Mon Sep 17 00:00:00 2001
From: Matt Arsenault <Matthew.Arsenault@amd.com>
Date: Fri, 14 Nov 2025 21:47:26 -0800
Subject: [PATCH] DAG: Use poison when splitting vector_shuffle results

---
 llvm/lib/CodeGen/SelectionDAG/LegalizeVectorTypes.cpp | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/llvm/lib/CodeGen/SelectionDAG/LegalizeVectorTypes.cpp b/llvm/lib/CodeGen/SelectionDAG/LegalizeVectorTypes.cpp
index 71eeee78bd868..ef53ee6df9f06 100644
--- a/llvm/lib/CodeGen/SelectionDAG/LegalizeVectorTypes.cpp
+++ b/llvm/lib/CodeGen/SelectionDAG/LegalizeVectorTypes.cpp
@@ -2922,7 +2922,7 @@ void DAGTypeLegalizer::SplitVecRes_VECTOR_SHUFFLE(ShuffleVectorSDNode *N,
            Input2->getOpcode() == ISD::BUILD_VECTOR &&
            "Expected build vector node.");
     EVT EltVT = NewVT.getVectorElementType();
-    SmallVector<SDValue> Ops(NewElts, DAG.getUNDEF(EltVT));
+    SmallVector<SDValue> Ops(NewElts, DAG.getPOISON(EltVT));
     for (unsigned I = 0; I < NewElts; ++I) {
       if (Mask[I] == PoisonMaskElem)
         continue;