1/*
2 * Copyright (c) 2015, 2015, Oracle and/or its affiliates. All rights reserved.
3 * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER.
4 *
5 * This code is free software; you can redistribute it and/or modify it
6 * under the terms of the GNU General Public License version 2 only, as
7 * published by the Free Software Foundation.
8 *
9 * This code is distributed in the hope that it will be useful, but WITHOUT
10 * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
11 * FITNESS FOR A PARTICULAR PURPOSE.  See the GNU General Public License
12 * version 2 for more details (a copy is included in the LICENSE file that
13 * accompanied this code).
14 *
15 * You should have received a copy of the GNU General Public License version
16 * 2 along with this work; if not, write to the Free Software Foundation,
17 * Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA.
18 *
19 * Please contact Oracle, 500 Oracle Parkway, Redwood Shores, CA 94065 USA
20 * or visit www.oracle.com if you need additional information or have any
21 * questions.
22 */
23package org.graalvm.compiler.api.directives.test;
24
25import org.graalvm.compiler.api.directives.GraalDirectives;
26import org.graalvm.compiler.core.test.GraalCompilerTest;
27import org.graalvm.compiler.graph.iterators.NodeIterable;
28import org.graalvm.compiler.nodes.AbstractBeginNode;
29import org.graalvm.compiler.nodes.IfNode;
30import org.graalvm.compiler.nodes.ReturnNode;
31import org.graalvm.compiler.nodes.StructuredGraph;
32import org.graalvm.compiler.nodes.debug.ControlFlowAnchorNode;
33import org.junit.Assert;
34import org.junit.Test;
35
36public class ProbabilityDirectiveTest extends GraalCompilerTest {
37
38    public static int branchProbabilitySnippet(int arg) {
39        if (GraalDirectives.injectBranchProbability(0.125, arg > 0)) {
40            GraalDirectives.controlFlowAnchor(); // prevent removal of the if
41            return 1;
42        } else {
43            GraalDirectives.controlFlowAnchor(); // prevent removal of the if
44            return 2;
45        }
46    }
47
48    @Test
49    public void testBranchProbability() {
50        test("branchProbabilitySnippet", 5);
51    }
52
53    @Override
54    protected boolean checkLowTierGraph(StructuredGraph graph) {
55        NodeIterable<IfNode> ifNodes = graph.getNodes(IfNode.TYPE);
56        Assert.assertEquals("IfNode count", 1, ifNodes.count());
57
58        IfNode ifNode = ifNodes.first();
59        AbstractBeginNode oneSuccessor;
60        if (returnValue(ifNode.trueSuccessor()) == 1) {
61            oneSuccessor = ifNode.trueSuccessor();
62        } else {
63            assert returnValue(ifNode.falseSuccessor()) == 1;
64            oneSuccessor = ifNode.falseSuccessor();
65        }
66        Assert.assertEquals("branch probability of " + ifNode, 0.125, ifNode.probability(oneSuccessor), 0);
67
68        return true;
69    }
70
71    private static int returnValue(AbstractBeginNode b) {
72        ControlFlowAnchorNode anchor = (ControlFlowAnchorNode) b.next();
73        ReturnNode returnNode = (ReturnNode) anchor.next();
74        return returnNode.result().asJavaConstant().asInt();
75    }
76}
77