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 * FITNESS FOR A PARTICULAR PURPOSE.  See the GNU General Public License

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 * You should have received a copy of the GNU General Public License version

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package org.graalvm.compiler.replacements.test;

import static org.junit.Assert.assertNotNull;

import java.util.ArrayList;

import java.util.Collection;

import java.util.List;

import org.graalvm.compiler.core.common.type.IntegerStamp;

import org.graalvm.compiler.core.common.type.StampFactory;

import org.graalvm.compiler.core.test.GraalCompilerTest;

import org.graalvm.compiler.graph.Node;

import org.graalvm.compiler.nodes.NodeView;

import org.graalvm.compiler.nodes.ParameterNode;

import org.graalvm.compiler.nodes.PiNode;

import org.graalvm.compiler.nodes.ReturnNode;

import org.graalvm.compiler.nodes.StructuredGraph;

import org.graalvm.compiler.nodes.StructuredGraph.AllowAssumptions;

import org.graalvm.compiler.nodes.StructuredGraph.GuardsStage;

import org.graalvm.compiler.nodes.ValueNode;

import org.graalvm.compiler.nodes.spi.LoweringTool;

import org.graalvm.compiler.phases.common.CanonicalizerPhase;

import org.graalvm.compiler.phases.common.LoweringPhase;

import org.graalvm.compiler.phases.tiers.HighTierContext;

import org.graalvm.compiler.phases.tiers.PhaseContext;

import org.graalvm.compiler.replacements.nodes.arithmetic.IntegerExactArithmeticNode;

import org.graalvm.compiler.replacements.nodes.arithmetic.IntegerExactArithmeticSplitNode;

import org.junit.Assert;

import org.junit.Test;

import org.junit.runner.RunWith;

import org.junit.runners.Parameterized;

import org.junit.runners.Parameterized.Parameters;

@RunWith(Parameterized.class)

public class IntegerExactFoldTest extends GraalCompilerTest {

    private final long lowerBoundA;

    private final long upperBoundA;

    private final long lowerBoundB;

    private final long upperBoundB;

    private final int bits;

    private final Operation operation;

    public IntegerExactFoldTest(long lowerBoundA, long upperBoundA, long lowerBoundB, long upperBoundB, int bits, Operation operation) {

        this.lowerBoundA = lowerBoundA;

        this.upperBoundA = upperBoundA;

        this.lowerBoundB = lowerBoundB;

        this.upperBoundB = upperBoundB;

        this.bits = bits;

        this.operation = operation;

        assert bits == 32 || bits == 64;

        assert lowerBoundA <= upperBoundA;

        assert lowerBoundB <= upperBoundB;

        assert bits == 64 || isInteger(lowerBoundA);

        assert bits == 64 || isInteger(upperBoundA);

        assert bits == 64 || isInteger(lowerBoundB);

        assert bits == 64 || isInteger(upperBoundB);

    }

    @Test

    public void testFolding() {

        StructuredGraph graph = prepareGraph();

        IntegerStamp a = StampFactory.forInteger(bits, lowerBoundA, upperBoundA);

        IntegerStamp b = StampFactory.forInteger(bits, lowerBoundB, upperBoundB);

        List<ParameterNode> params = graph.getNodes(ParameterNode.TYPE).snapshot();

        params.get(0).replaceAtMatchingUsages(graph.addOrUnique(new PiNode(params.get(0), a)), x -> x instanceof IntegerExactArithmeticNode);

        params.get(1).replaceAtMatchingUsages(graph.addOrUnique(new PiNode(params.get(1), b)), x -> x instanceof IntegerExactArithmeticNode);

        Node originalNode = graph.getNodes().filter(x -> x instanceof IntegerExactArithmeticNode).first();

        assertNotNull("original node must be in the graph", originalNode);

        new CanonicalizerPhase().apply(graph, getDefaultHighTierContext());

        ValueNode node = findNode(graph);

        boolean overflowExpected = node instanceof IntegerExactArithmeticNode;

        IntegerStamp resultStamp = (IntegerStamp) node.stamp(NodeView.DEFAULT);

        operation.verifyOverflow(lowerBoundA, upperBoundA, lowerBoundB, upperBoundB, bits, overflowExpected, resultStamp);

    }

    @Test

    public void testFoldingAfterLowering() {

        StructuredGraph graph = prepareGraph();

        Node originalNode = graph.getNodes().filter(x -> x instanceof IntegerExactArithmeticNode).first();

        assertNotNull("original node must be in the graph", originalNode);

        graph.setGuardsStage(GuardsStage.FIXED_DEOPTS);

        CanonicalizerPhase canonicalizer = new CanonicalizerPhase();

        PhaseContext context = new PhaseContext(getProviders());

        new LoweringPhase(canonicalizer, LoweringTool.StandardLoweringStage.HIGH_TIER).apply(graph, context);

        IntegerExactArithmeticSplitNode loweredNode = graph.getNodes().filter(IntegerExactArithmeticSplitNode.class).first();

        assertNotNull("the lowered node must be in the graph", loweredNode);

        loweredNode.getX().setStamp(StampFactory.forInteger(bits, lowerBoundA, upperBoundA));

        loweredNode.getY().setStamp(StampFactory.forInteger(bits, lowerBoundB, upperBoundB));

        new CanonicalizerPhase().apply(graph, context);

        ValueNode node = findNode(graph);

        boolean overflowExpected = node instanceof IntegerExactArithmeticSplitNode;

        IntegerStamp resultStamp = (IntegerStamp) node.stamp(NodeView.DEFAULT);

        operation.verifyOverflow(lowerBoundA, upperBoundA, lowerBoundB, upperBoundB, bits, overflowExpected, resultStamp);

    }

    private static boolean isInteger(long value) {

        return value >= Integer.MIN_VALUE && value <= Integer.MAX_VALUE;

    }

    private static ValueNode findNode(StructuredGraph graph) {

        ValueNode resultNode = graph.getNodes().filter(ReturnNode.class).first().result();

        assertNotNull("some node must be the returned value", resultNode);

        return resultNode;

    }

    protected StructuredGraph prepareGraph() {

        String snippet = "snippetInt" + bits;

        StructuredGraph graph = parseEager(getResolvedJavaMethod(operation.getClass(), snippet), AllowAssumptions.NO);

        HighTierContext context = getDefaultHighTierContext();

        new CanonicalizerPhase().apply(graph, context);

        return graph;

    }

    private static void addTest(ArrayList<Object[]> tests, long lowerBound1, long upperBound1, long lowerBound2, long upperBound2, int bits, Operation operation) {

        tests.add(new Object[]{lowerBound1, upperBound1, lowerBound2, upperBound2, bits, operation});

    }

    @Parameters(name = "a[{0} / {1}], b[{2} / {3}], bits={4}, operation={5}")

    public static Collection<Object[]> data() {

        ArrayList<Object[]> tests = new ArrayList<>();

        Operation[] operations = new Operation[]{new AddOperation(), new SubOperation(), new MulOperation()};

        for (Operation operation : operations) {

            for (int bits : new int[]{32, 64}) {

                // zero related

                addTest(tests, 0, 0, 1, 1, bits, operation);

                addTest(tests, 1, 1, 0, 0, bits, operation);

                addTest(tests, -1, 1, 0, 1, bits, operation);

                // bounds

                addTest(tests, -2, 2, 3, 3, bits, operation);

                addTest(tests, -1, 1, 1, 1, bits, operation);

                addTest(tests, -1, 1, -1, 1, bits, operation);

                addTest(tests, Integer.MIN_VALUE, Integer.MIN_VALUE + 0xF, Integer.MAX_VALUE - 0xF, Integer.MAX_VALUE, bits, operation);

                addTest(tests, Integer.MIN_VALUE, Integer.MIN_VALUE + 0xF, -1, -1, bits, operation);

                addTest(tests, Integer.MAX_VALUE, Integer.MAX_VALUE, -1, -1, bits, operation);

                addTest(tests, Integer.MIN_VALUE, Integer.MIN_VALUE, -1, -1, bits, operation);

                addTest(tests, Integer.MAX_VALUE, Integer.MAX_VALUE, 1, 1, bits, operation);

                addTest(tests, Integer.MIN_VALUE, Integer.MIN_VALUE, 1, 1, bits, operation);

            }

            // bit-specific test cases

            addTest(tests, Integer.MIN_VALUE, Integer.MIN_VALUE + 0xF, Integer.MAX_VALUE - 0xF, Integer.MAX_VALUE, 64, operation);

            addTest(tests, Integer.MIN_VALUE, Integer.MIN_VALUE + 0xF, -1, -1, 64, operation);

        }

        return tests;

    }

    private abstract static class Operation {

        abstract void verifyOverflow(long lowerBoundA, long upperBoundA, long lowerBoundB, long upperBoundB, int bits, boolean overflowExpected, IntegerStamp resultStamp);

    }

    private static final class AddOperation extends Operation {

        @Override

        public void verifyOverflow(long lowerBoundA, long upperBoundA, long lowerBoundB, long upperBoundB, int bits, boolean overflowExpected, IntegerStamp resultStamp) {

            try {

                long res = addExact(lowerBoundA, lowerBoundB, bits);

                resultStamp.contains(res);

                res = addExact(upperBoundA, upperBoundB, bits);

                resultStamp.contains(res);

                Assert.assertFalse(overflowExpected);

            } catch (ArithmeticException e) {

                Assert.assertTrue(overflowExpected);

            }

        }

        private static long addExact(long x, long y, int bits) {

            if (bits == 32) {

                return Math.addExact((int) x, (int) y);

            } else {

                return Math.addExact(x, y);

            }

        }

        @SuppressWarnings("unused")

        public static int snippetInt32(int a, int b) {

            return Math.addExact(a, b);

        }

        @SuppressWarnings("unused")

        public static long snippetInt64(long a, long b) {

            return Math.addExact(a, b);

        }

    }

    private static final class SubOperation extends Operation {

        @Override

        public void verifyOverflow(long lowerBoundA, long upperBoundA, long lowerBoundB, long upperBoundB, int bits, boolean overflowExpected, IntegerStamp resultStamp) {

            try {

                long res = subExact(lowerBoundA, upperBoundB, bits);

                Assert.assertTrue(resultStamp.contains(res));

                res = subExact(upperBoundA, lowerBoundB, bits);

                Assert.assertTrue(resultStamp.contains(res));

                Assert.assertFalse(overflowExpected);

            } catch (ArithmeticException e) {

                Assert.assertTrue(overflowExpected);

            }

        }

        private static long subExact(long x, long y, int bits) {

            if (bits == 32) {

                return Math.subtractExact((int) x, (int) y);

            } else {

                return Math.subtractExact(x, y);

            }

        }

        @SuppressWarnings("unused")

        public static int snippetInt32(int a, int b) {

            return Math.subtractExact(a, b);

        }

        @SuppressWarnings("unused")

        public static long snippetInt64(long a, long b) {

            return Math.subtractExact(a, b);

        }

    }

    private static final class MulOperation extends Operation {

        @Override

        public void verifyOverflow(long lowerBoundA, long upperBoundA, long lowerBoundB, long upperBoundB, int bits, boolean overflowExpected, IntegerStamp resultStamp) {

            // now check for all values in the stamp whether their products overflow overflow

            boolean overflowOccurred = false;

            for (long l1 = lowerBoundA; l1 <= upperBoundA; l1++) {

                for (long l2 = lowerBoundB; l2 <= upperBoundB; l2++) {

                    try {

                        long res = mulExact(l1, l2, bits);

                        Assert.assertTrue(resultStamp.contains(res));

                    } catch (ArithmeticException e) {

                        overflowOccurred = true;

                    }

                    if (l2 == Long.MAX_VALUE) {

                        // do not want to overflow the check loop

                        break;

                    }

                }

                if (l1 == Long.MAX_VALUE) {

                    // do not want to overflow the check loop

                    break;

                }

            }

            Assert.assertEquals(overflowExpected, overflowOccurred);

        }

        private static long mulExact(long x, long y, int bits) {

            if (bits == 32) {

                return Math.multiplyExact((int) x, (int) y);

            } else {

                return Math.multiplyExact(x, y);

            }

        }

        @SuppressWarnings("unused")

        public static int snippetInt32(int a, int b) {

            return Math.multiplyExact(a, b);

        }

        @SuppressWarnings("unused")

        public static long snippetInt64(long a, long b) {

            return Math.multiplyExact(a, b);

        }

    }

}