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package org.graalvm.compiler.loop;

import org.graalvm.compiler.core.common.type.IntegerStamp;
import org.graalvm.compiler.nodes.FixedNode;
import org.graalvm.compiler.nodes.NodeView;
import org.graalvm.compiler.nodes.StructuredGraph;
import org.graalvm.compiler.nodes.ValueNode;
import org.graalvm.compiler.nodes.calc.BinaryArithmeticNode;
import org.graalvm.compiler.nodes.calc.FixedBinaryNode;
import org.graalvm.compiler.nodes.calc.SignedDivNode;
import org.graalvm.compiler.nodes.calc.UnsignedDivNode;
import org.graalvm.compiler.nodes.extended.GuardingNode;

import java.util.function.BiFunction;

Utility methods to perform integer math with some obvious constant folding first.
/** * Utility methods to perform integer math with some obvious constant folding first. */
public class MathUtil { private static boolean isConstantOne(ValueNode v1) { return v1.isConstant() && v1.stamp(NodeView.DEFAULT) instanceof IntegerStamp && v1.asJavaConstant().asLong() == 1; } private static boolean isConstantZero(ValueNode v1) { return v1.isConstant() && v1.stamp(NodeView.DEFAULT) instanceof IntegerStamp && v1.asJavaConstant().asLong() == 0; } public static ValueNode add(StructuredGraph graph, ValueNode v1, ValueNode v2) { if (isConstantZero(v1)) { return v2; } if (isConstantZero(v2)) { return v1; } return BinaryArithmeticNode.add(graph, v1, v2, NodeView.DEFAULT); } public static ValueNode mul(StructuredGraph graph, ValueNode v1, ValueNode v2) { if (isConstantOne(v1)) { return v2; } if (isConstantOne(v2)) { return v1; } return BinaryArithmeticNode.mul(graph, v1, v2, NodeView.DEFAULT); } public static ValueNode sub(StructuredGraph graph, ValueNode v1, ValueNode v2) { if (isConstantZero(v2)) { return v1; } return BinaryArithmeticNode.sub(graph, v1, v2, NodeView.DEFAULT); } public static ValueNode divBefore(StructuredGraph graph, FixedNode before, ValueNode dividend, ValueNode divisor, GuardingNode zeroCheck) { return fixedDivBefore(graph, before, dividend, divisor, (dend, sor) -> SignedDivNode.create(dend, sor, zeroCheck, NodeView.DEFAULT)); } public static ValueNode unsignedDivBefore(StructuredGraph graph, FixedNode before, ValueNode dividend, ValueNode divisor, GuardingNode zeroCheck) { return fixedDivBefore(graph, before, dividend, divisor, (dend, sor) -> UnsignedDivNode.create(dend, sor, zeroCheck, NodeView.DEFAULT)); } private static ValueNode fixedDivBefore(StructuredGraph graph, FixedNode before, ValueNode dividend, ValueNode divisor, BiFunction<ValueNode, ValueNode, ValueNode> createDiv) { if (isConstantOne(divisor)) { return dividend; } ValueNode div = createDiv.apply(dividend, divisor); if (div instanceof FixedBinaryNode) { FixedBinaryNode fixedDiv = (FixedBinaryNode) div; if (before.predecessor() instanceof FixedBinaryNode) { FixedBinaryNode binaryPredecessor = (FixedBinaryNode) before.predecessor(); if (fixedDiv.dataFlowEquals(binaryPredecessor)) { if (fixedDiv.isAlive()) { fixedDiv.safeDelete(); } return binaryPredecessor; } } graph.addBeforeFixed(before, graph.addOrUniqueWithInputs(fixedDiv)); } return div; } }