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  */
  23 package org.graalvm.compiler.api.directives.test;
  24 
  25 import org.junit.Assert;
  26 import org.junit.Test;
  27 
  28 import org.graalvm.compiler.api.directives.GraalDirectives;
  29 import org.graalvm.compiler.core.test.GraalCompilerTest;
  30 import org.graalvm.compiler.graph.iterators.NodeIterable;
  31 import org.graalvm.compiler.nodes.AbstractBeginNode;
  32 import org.graalvm.compiler.nodes.IfNode;
  33 import org.graalvm.compiler.nodes.StructuredGraph;
  34 
  35 public class ProbabilityDirectiveTest extends GraalCompilerTest {
  36 
  37     public static int branchProbabilitySnippet(int arg) {
  38         if (GraalDirectives.injectBranchProbability(0.125, arg > 0)) {
  39             GraalDirectives.controlFlowAnchor(); // prevent removal of the if
  40             return 1;
  41         } else {
  42             GraalDirectives.controlFlowAnchor(); // prevent removal of the if
  43             return 2;
  44         }
  45     }
  46 
  47     @Test
  48     public void testBranchProbability() {
  49         test("branchProbabilitySnippet", 5);
  50     }
  51 
  52     @Override
  53     protected boolean checkLowTierGraph(StructuredGraph graph) {
  54         NodeIterable<IfNode> ifNodes = graph.getNodes(IfNode.TYPE);
  55         Assert.assertEquals("IfNode count", 1, ifNodes.count());
  56 
  57         IfNode ifNode = ifNodes.first();
  58         AbstractBeginNode trueSuccessor = ifNode.trueSuccessor();
  59         Assert.assertEquals("branch probability of " + ifNode, 0.125, ifNode.probability(trueSuccessor), 0);
  60 
  61         return true;
  62     }
  63 }