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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,

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

import org.graalvm.compiler.nodes.IfNode;

import org.graalvm.compiler.nodes.ReturnNode;

import org.graalvm.compiler.nodes.StructuredGraph;

import org.graalvm.compiler.nodes.debug.ControlFlowAnchorNode;

import org.junit.Assert;

import org.junit.Test;

public class ProbabilityDirectiveTest extends GraalCompilerTest {

    public static int branchProbabilitySnippet(int arg) {

        if (GraalDirectives.injectBranchProbability(0.125, arg > 0)) {

            GraalDirectives.controlFlowAnchor(); // prevent removal of the if

            return 1;

        } else {

            GraalDirectives.controlFlowAnchor(); // prevent removal of the if

            return 2;

        }

    }

    @Test

    public void testBranchProbability() {

        test("branchProbabilitySnippet", 5);

    }

    @Override

    protected boolean checkLowTierGraph(StructuredGraph graph) {

        NodeIterable<IfNode> ifNodes = graph.getNodes(IfNode.TYPE);

        Assert.assertEquals("IfNode count", 1, ifNodes.count());

        IfNode ifNode = ifNodes.first();

        AbstractBeginNode oneSuccessor;

        if (returnValue(ifNode.trueSuccessor()) == 1) {

            oneSuccessor = ifNode.trueSuccessor();

        } else {

            assert returnValue(ifNode.falseSuccessor()) == 1;

            oneSuccessor = ifNode.falseSuccessor();

        }

        Assert.assertEquals("branch probability of " + ifNode, 0.125, ifNode.probability(oneSuccessor), 0);

        return true;

    }

    private static int returnValue(AbstractBeginNode b) {

        ControlFlowAnchorNode anchor = (ControlFlowAnchorNode) b.next();

        ReturnNode returnNode = (ReturnNode) anchor.next();

        return returnNode.result().asJavaConstant().asInt();

    }

}