diff --git a/contrib/llvm-project/llvm/lib/Target/ARM/ARMISelDAGToDAG.cpp b/contrib/llvm-project/llvm/lib/Target/ARM/ARMISelDAGToDAG.cpp
index 9c7055deaaf..7c238a1099d 100644
--- a/contrib/llvm-project/llvm/lib/Target/ARM/ARMISelDAGToDAG.cpp
+++ b/contrib/llvm-project/llvm/lib/Target/ARM/ARMISelDAGToDAG.cpp
@@ -79,6 +79,10 @@ public:
 
   void Select(SDNode *N) override;
 
+  /// Return true as some complex patterns, like those that call
+  /// canExtractShiftFromMul can modify the DAG inplace.
+  bool ComplexPatternFuncMutatesDAG() const override { return true; }
+
   bool hasNoVMLxHazardUse(SDNode *N) const;
   bool isShifterOpProfitable(const SDValue &Shift,
                              ARM_AM::ShiftOpc ShOpcVal, unsigned ShAmt);