63     public ValueNode canonical(CanonicalizerTool tool, ValueNode forX, ValueNode forY) {
  64         NodeView view = NodeView.from(tool);
  65         ValueNode ret = super.canonical(tool, forX, forY);
  66         if (ret != this) {
  67             return ret;
  68         }
  69 
  70         return canonical(this, this.getArithmeticOp(), this.stamp(view), forX, forY, view);
  71     }
  72 
  73     @SuppressWarnings("unused")
  74     private static ValueNode canonical(UnsignedRightShiftNode node, ArithmeticOpTable.ShiftOp<UShr> op, Stamp stamp, ValueNode forX, ValueNode forY, NodeView view) {
  75         if (forY.isConstant()) {
  76             int amount = forY.asJavaConstant().asInt();
  77             int originalAmout = amount;
  78             int mask = op.getShiftAmountMask(stamp);
  79             amount &= mask;
  80             if (amount == 0) {
  81                 return forX;
  82             }
















  83             if (forX instanceof ShiftNode) {
  84                 ShiftNode<?> other = (ShiftNode<?>) forX;
  85                 if (other.getY().isConstant()) {
  86                     int otherAmount = other.getY().asJavaConstant().asInt() & mask;
  87                     if (other instanceof UnsignedRightShiftNode) {
  88                         int total = amount + otherAmount;
  89                         if (total != (total & mask)) {
  90                             return ConstantNode.forIntegerKind(stamp.getStackKind(), 0);
  91                         }
  92                         return new UnsignedRightShiftNode(other.getX(), ConstantNode.forInt(total));
  93                     } else if (other instanceof LeftShiftNode && otherAmount == amount) {
  94                         if (stamp.getStackKind() == JavaKind.Long) {
  95                             return new AndNode(other.getX(), ConstantNode.forLong(-1L >>> amount));
  96                         } else {
  97                             assert stamp.getStackKind() == JavaKind.Int;
  98                             return new AndNode(other.getX(), ConstantNode.forInt(-1 >>> amount));
  99                         }
 100                     }
 101                 }
 102             }

  63     public ValueNode canonical(CanonicalizerTool tool, ValueNode forX, ValueNode forY) {
  64         NodeView view = NodeView.from(tool);
  65         ValueNode ret = super.canonical(tool, forX, forY);
  66         if (ret != this) {
  67             return ret;
  68         }
  69 
  70         return canonical(this, this.getArithmeticOp(), this.stamp(view), forX, forY, view);
  71     }
  72 
  73     @SuppressWarnings("unused")
  74     private static ValueNode canonical(UnsignedRightShiftNode node, ArithmeticOpTable.ShiftOp<UShr> op, Stamp stamp, ValueNode forX, ValueNode forY, NodeView view) {
  75         if (forY.isConstant()) {
  76             int amount = forY.asJavaConstant().asInt();
  77             int originalAmout = amount;
  78             int mask = op.getShiftAmountMask(stamp);
  79             amount &= mask;
  80             if (amount == 0) {
  81                 return forX;
  82             }
  83 
  84             Stamp xStampGeneric = forX.stamp(view);
  85             if (xStampGeneric instanceof IntegerStamp) {
  86                 IntegerStamp xStamp = (IntegerStamp) xStampGeneric;
  87 
  88                 if (xStamp.lowerBound() >>> amount == xStamp.upperBound() >>> amount) {
  89                     // The result of the shift is constant.
  90                     return ConstantNode.forIntegerKind(stamp.getStackKind(), xStamp.lowerBound() >>> amount);
  91                 }
  92 
  93                 if (amount == xStamp.getBits() - 1 && xStamp.lowerBound() == -1 && xStamp.upperBound() == 0) {
  94                     // Shift is equivalent to a negation, i.e., turns -1 into 1 and keeps 0 at 0.
  95                     return NegateNode.create(forX, view);
  96                 }
  97             }
  98 
  99             if (forX instanceof ShiftNode) {
 100                 ShiftNode<?> other = (ShiftNode<?>) forX;
 101                 if (other.getY().isConstant()) {
 102                     int otherAmount = other.getY().asJavaConstant().asInt() & mask;
 103                     if (other instanceof UnsignedRightShiftNode) {
 104                         int total = amount + otherAmount;
 105                         if (total != (total & mask)) {
 106                             return ConstantNode.forIntegerKind(stamp.getStackKind(), 0);
 107                         }
 108                         return new UnsignedRightShiftNode(other.getX(), ConstantNode.forInt(total));
 109                     } else if (other instanceof LeftShiftNode && otherAmount == amount) {
 110                         if (stamp.getStackKind() == JavaKind.Long) {
 111                             return new AndNode(other.getX(), ConstantNode.forLong(-1L >>> amount));
 112                         } else {
 113                             assert stamp.getStackKind() == JavaKind.Int;
 114                             return new AndNode(other.getX(), ConstantNode.forInt(-1 >>> amount));
 115                         }
 116                     }
 117                 }
 118             }