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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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package org.graalvm.compiler.api.directives.test;

import org.junit.Assert;

import org.junit.Test;

import org.graalvm.compiler.api.directives.GraalDirectives;

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

import org.graalvm.compiler.graph.iterators.NodeIterable;

import org.graalvm.compiler.nodes.LoopBeginNode;

import org.graalvm.compiler.nodes.StructuredGraph;

public class IterationDirectiveTest extends GraalCompilerTest {

    public static int loopFrequencySnippet(int arg) {

        int x = arg;

        while (GraalDirectives.injectIterationCount(128, x > 1)) {

            GraalDirectives.controlFlowAnchor(); // prevent loop peeling or unrolling

            if (x % 2 == 0) {

                x /= 2;

            } else {

                x = 3 * x + 1;

            }

        }

        return x;

    }

    @Test

    public void testLoopFrequency() {

        test("loopFrequencySnippet", 7);

    }

    @Override

    protected boolean checkLowTierGraph(StructuredGraph graph) {

        NodeIterable<LoopBeginNode> loopBeginNodes = graph.getNodes(LoopBeginNode.TYPE);

        Assert.assertEquals("LoopBeginNode count", 1, loopBeginNodes.count());

        LoopBeginNode loopBeginNode = loopBeginNodes.first();

        Assert.assertEquals("loop frequency of " + loopBeginNode, 128, loopBeginNode.loopFrequency(), 0);

        return true;

    }

}