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package org.graalvm.compiler.nodes.calc;

import static org.graalvm.compiler.nodeinfo.NodeCycles.CYCLES_1;
import static org.graalvm.compiler.nodeinfo.NodeSize.SIZE_1;

import java.io.Serializable;
import java.util.function.Function;

import org.graalvm.compiler.core.common.type.ArithmeticOpTable;
import org.graalvm.compiler.core.common.type.ArithmeticOpTable.ShiftOp;
import org.graalvm.compiler.core.common.type.IntegerStamp;
import org.graalvm.compiler.core.common.type.Stamp;
import org.graalvm.compiler.graph.NodeClass;
import org.graalvm.compiler.graph.spi.CanonicalizerTool;
import org.graalvm.compiler.nodeinfo.NodeInfo;
import org.graalvm.compiler.nodes.ArithmeticOperation;
import org.graalvm.compiler.nodes.ConstantNode;
import org.graalvm.compiler.nodes.NodeView;
import org.graalvm.compiler.nodes.ValueNode;
import org.graalvm.compiler.nodes.spi.ArithmeticLIRLowerable;

import jdk.vm.ci.code.CodeUtil;
import jdk.vm.ci.meta.JavaConstant;
import jdk.vm.ci.meta.JavaKind;

The ShiftOp class represents shift operations.
/** * The {@code ShiftOp} class represents shift operations. */
@NodeInfo(cycles = CYCLES_1, size = SIZE_1) public abstract class ShiftNode<OP> extends BinaryNode implements ArithmeticOperation, ArithmeticLIRLowerable, NarrowableArithmeticNode { @SuppressWarnings("rawtypes") public static final NodeClass<ShiftNode> TYPE = NodeClass.create(ShiftNode.class); protected interface SerializableShiftFunction<T> extends Function<ArithmeticOpTable, ShiftOp<T>>, Serializable { } protected final SerializableShiftFunction<OP> getOp;
Creates a new shift operation.
Params:
  • x – the first input value
  • s – the second input value
/** * Creates a new shift operation. * * @param x the first input value * @param s the second input value */
protected ShiftNode(NodeClass<? extends ShiftNode<OP>> c, SerializableShiftFunction<OP> getOp, ValueNode x, ValueNode s) { super(c, getOp.apply(ArithmeticOpTable.forStamp(x.stamp(NodeView.DEFAULT))).foldStamp(x.stamp(NodeView.DEFAULT), (IntegerStamp) s.stamp(NodeView.DEFAULT)), x, s); assert ((IntegerStamp) s.stamp(NodeView.DEFAULT)).getBits() == 32; this.getOp = getOp; } protected final ShiftOp<OP> getOp(ValueNode forValue) { return getOp.apply(ArithmeticOpTable.forStamp(forValue.stamp(NodeView.DEFAULT))); } @Override public final ShiftOp<OP> getArithmeticOp() { return getOp(getX()); } @Override public Stamp foldStamp(Stamp stampX, Stamp stampY) { return getArithmeticOp().foldStamp(stampX, (IntegerStamp) stampY); } @Override public ValueNode canonical(CanonicalizerTool tool, ValueNode forX, ValueNode forY) { NodeView view = NodeView.from(tool); ValueNode valueNode = canonical(getOp(forX), stamp(NodeView.DEFAULT), forX, forY, view); if (valueNode != null) { return valueNode; } return this; } @SuppressWarnings("unused") public static <OP> ValueNode canonical(ShiftOp<OP> op, Stamp stamp, ValueNode forX, ValueNode forY, NodeView view) { if (forX.isConstant() && forY.isConstant()) { JavaConstant amount = forY.asJavaConstant(); assert amount.getJavaKind() == JavaKind.Int; return ConstantNode.forPrimitive(stamp, op.foldConstant(forX.asConstant(), amount.asInt())); } return null; } public int getShiftAmountMask() { return getArithmeticOp().getShiftAmountMask(stamp(NodeView.DEFAULT)); } @Override public boolean isNarrowable(int resultBits) { assert CodeUtil.isPowerOf2(resultBits); int narrowMask = resultBits - 1; int wideMask = getShiftAmountMask(); assert (wideMask & narrowMask) == narrowMask : String.format("wideMask %x should be wider than narrowMask %x", wideMask, narrowMask); /* * Shifts are special because narrowing them also changes the implicit mask of the shift * amount. We can narrow only if (y & wideMask) == (y & narrowMask) for all possible values * of y. */ IntegerStamp yStamp = (IntegerStamp) getY().stamp(NodeView.DEFAULT); return (yStamp.upMask() & (wideMask & ~narrowMask)) == 0; } }