[llvm] 0b921f5 - DAG: Use poison when splitting vector_shuffle results (#168176)

[via llvm-commits]

Author: Matt Arsenault
Date: 2025-11-19T12:27:08-05:00
New Revision: 0b921f52cc9313b89ca8fe2707d90cb1c2809387

URL: https://github.com/llvm/llvm-project/commit/0b921f52cc9313b89ca8fe2707d90cb1c2809387
DIFF: https://github.com/llvm/llvm-project/commit/0b921f52cc9313b89ca8fe2707d90cb1c2809387.diff

LOG: DAG: Use poison when splitting vector_shuffle results (#168176)

Added: 
    

Modified: 
    llvm/lib/CodeGen/SelectionDAG/LegalizeVectorTypes.cpp

Removed: 
    


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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;