2 files changed, 18 insertions, 0 deletions
diff --git a/llvm/lib/Target/AArch64/AArch64ISelLowering.cpp b/llvm/lib/Target/AArch64/AArch64ISelLowering.cpp
index b78837aae83..381d0ae41c7 100644
--- a/llvm/lib/Target/AArch64/AArch64ISelLowering.cpp
+++ b/llvm/lib/Target/AArch64/AArch64ISelLowering.cpp
@@ -12042,6 +12042,19 @@ bool AArch64TargetLowering::isMaskAndCmp0FoldingBeneficial(
   return Mask->getValue().isPowerOf2();
 }
 
+bool AArch64TargetLowering::
+    shouldProduceAndByConstByHoistingConstFromShiftsLHSOfAnd(
+        SDValue X, ConstantSDNode *XC, ConstantSDNode *CC, SDValue Y,
+        unsigned OldShiftOpcode, unsigned NewShiftOpcode,
+        SelectionDAG &DAG) const {
+  // Does baseline recommend not to perform the fold by default?
+  if (!TargetLowering::shouldProduceAndByConstByHoistingConstFromShiftsLHSOfAnd(
+          X, XC, CC, Y, OldShiftOpcode, NewShiftOpcode, DAG))
+    return false;
+  // Else, if this is a vector shift, prefer 'shl'.
+  return X.getValueType().isScalarInteger() || NewShiftOpcode == ISD::SHL;
+}
+
 void AArch64TargetLowering::initializeSplitCSR(MachineBasicBlock *Entry) const {
   // Update IsSplitCSR in AArch64unctionInfo.
   AArch64FunctionInfo *AFI = Entry->getParent()->getInfo<AArch64FunctionInfo>();
diff --git a/llvm/lib/Target/AArch64/AArch64ISelLowering.h b/llvm/lib/Target/AArch64/AArch64ISelLowering.h
index 34e1fdf441e..21a0b16e66b 100644
--- a/llvm/lib/Target/AArch64/AArch64ISelLowering.h
+++ b/llvm/lib/Target/AArch64/AArch64ISelLowering.h
@@ -488,6 +488,11 @@ public:
     return VT.getSizeInBits() >= 64; // vector 'bic'
   }
 
+  bool shouldProduceAndByConstByHoistingConstFromShiftsLHSOfAnd(
+      SDValue X, ConstantSDNode *XC, ConstantSDNode *CC, SDValue Y,
+      unsigned OldShiftOpcode, unsigned NewShiftOpcode,
+      SelectionDAG &DAG) const override;
+
   bool shouldExpandShift(SelectionDAG &DAG, SDNode *N) const override {
     if (DAG.getMachineFunction().getFunction().hasMinSize())
       return false;