src/jdk.internal.vm.compiler/share/classes/org.graalvm.compiler.core.test/src/org/graalvm/compiler/core/test/MemoryGraphCanonicalizeTest.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
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package org.graalvm.compiler.core.test;

import org.graalvm.compiler.nodes.StructuredGraph;
import org.graalvm.compiler.nodes.memory.WriteNode;
import org.graalvm.compiler.nodes.spi.LoweringTool;
import org.graalvm.compiler.phases.common.CanonicalizerPhase;
import org.graalvm.compiler.phases.common.FloatingReadPhase;
import org.graalvm.compiler.phases.common.IncrementalCanonicalizerPhase;
import org.graalvm.compiler.phases.common.LoweringPhase;
import org.graalvm.compiler.phases.tiers.HighTierContext;
import org.junit.Test;

public class MemoryGraphCanonicalizeTest extends GraalCompilerTest {
    static class TestObject {
        Object object;
        Integer integer;
        int value;
        volatile boolean written;
    }

    public static void simpleElimination(TestObject object) {
        object.object = object;
        object.value = object.integer;
        object.value = object.integer + 2;
        object.value = object.integer + 3;
    }

    @Test
    public void testSimpleElimination() {
        testGraph("simpleElimination", 2);
    }

    public static void complexElimination(TestObject object) {
        object.object = object;
        object.value = object.integer;
        object.value = object.integer + 2;
        if (object.object == null) {
            object.value = object.integer + 3;
        } else {
            object.object = new Object();
        }
        object.written = true;
        object.value = 5;
    }

    @Test
    public void testComplexElimination() {
        testGraph("complexElimination", 6);
    }

    public void testGraph(String name, int expectedWrites) {
        StructuredGraph graph = parseEager(name, StructuredGraph.AllowAssumptions.YES);
        HighTierContext context = getDefaultHighTierContext();
        CanonicalizerPhase canonicalizer = new CanonicalizerPhase();
        new LoweringPhase(new CanonicalizerPhase(), LoweringTool.StandardLoweringStage.HIGH_TIER).apply(graph, context);
        new IncrementalCanonicalizerPhase<>(canonicalizer, new FloatingReadPhase()).apply(graph, context);
        new CanonicalizerPhase().apply(graph, context);
        int writes = graph.getNodes().filter(WriteNode.class).count();
        assertTrue(writes == expectedWrites, "Expected %d writes, found %d", expectedWrites, writes);
    }
}