hotspot/src/jdk.internal.vm.compiler/share/classes/org.graalvm.compiler.loop/src/org/graalvm/compiler/loop/DerivedScaledInductionVariable.java

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 * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.
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 * FITNESS FOR A PARTICULAR PURPOSE.  See the GNU General Public License
 * version 2 for more details (a copy is included in the LICENSE file that
 * accompanied this code).
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 * 2 along with this work; if not, write to the Free Software Foundation,
 * Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA.
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package org.graalvm.compiler.loop;

import static org.graalvm.compiler.loop.MathUtil.mul;

import org.graalvm.compiler.core.common.type.IntegerStamp;
import org.graalvm.compiler.core.common.type.Stamp;
import org.graalvm.compiler.nodes.ConstantNode;
import org.graalvm.compiler.nodes.ValueNode;
import org.graalvm.compiler.nodes.calc.IntegerConvertNode;
import org.graalvm.compiler.nodes.calc.NegateNode;
import org.graalvm.compiler.nodes.util.GraphUtil;

public class DerivedScaledInductionVariable extends DerivedInductionVariable {

    private final ValueNode scale;
    private final ValueNode value;

    public DerivedScaledInductionVariable(LoopEx loop, InductionVariable base, ValueNode scale, ValueNode value) {
        super(loop, base);
        this.scale = scale;
        this.value = value;
    }

    public DerivedScaledInductionVariable(LoopEx loop, InductionVariable base, NegateNode value) {
        super(loop, base);
        this.scale = ConstantNode.forIntegerStamp(value.stamp(), -1, value.graph());
        this.value = value;
    }

    public ValueNode getScale() {
        return scale;
    }

    @Override
    public ValueNode valueNode() {
        return value;
    }

    @Override
    public Direction direction() {
        Stamp stamp = scale.stamp();
        if (stamp instanceof IntegerStamp) {
            IntegerStamp integerStamp = (IntegerStamp) stamp;
            if (integerStamp.isStrictlyPositive()) {
                return base.direction();
            } else if (integerStamp.isStrictlyNegative()) {
                return base.direction().opposite();
            }
        }
        return null;
    }

    @Override
    public ValueNode initNode() {
        return mul(graph(), base.initNode(), scale);
    }

    @Override
    public ValueNode strideNode() {
        return mul(graph(), base.strideNode(), scale);
    }

    @Override
    public boolean isConstantInit() {
        return scale.isConstant() && base.isConstantInit();
    }

    @Override
    public boolean isConstantStride() {
        return scale.isConstant() && base.isConstantStride();
    }

    @Override
    public long constantInit() {
        return base.constantInit() * scale.asJavaConstant().asLong();
    }

    @Override
    public long constantStride() {
        return base.constantStride() * scale.asJavaConstant().asLong();
    }

    @Override
    public ValueNode extremumNode(boolean assumePositiveTripCount, Stamp stamp) {
        return mul(graph(), base.extremumNode(assumePositiveTripCount, stamp), IntegerConvertNode.convert(scale, stamp, graph()));
    }

    @Override
    public ValueNode exitValueNode() {
        return mul(graph(), base.exitValueNode(), scale);
    }

    @Override
    public boolean isConstantExtremum() {
        return scale.isConstant() && base.isConstantExtremum();
    }

    @Override
    public long constantExtremum() {
        return base.constantExtremum() * scale.asJavaConstant().asLong();
    }

    @Override
    public void deleteUnusedNodes() {
        if (scale.isAlive() && scale.hasNoUsages()) {
            GraphUtil.killWithUnusedFloatingInputs(scale);
        }
    }

    @Override
    public String toString() {
        return String.format("DerivedScaleInductionVariable base (%s) %s %s", base, value.getNodeClass().shortName(), scale);
    }
}