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 
  24 
  25 package org.graalvm.compiler.api.directives.test;
  26 
  27 import org.junit.Assert;
  28 import org.junit.Test;
  29 
  30 import org.graalvm.compiler.api.directives.GraalDirectives;
  31 import org.graalvm.compiler.core.test.GraalCompilerTest;
  32 import org.graalvm.compiler.graph.iterators.NodeIterable;
  33 import org.graalvm.compiler.nodes.LoopBeginNode;
  34 import org.graalvm.compiler.nodes.StructuredGraph;
  35 
  36 public class IterationDirectiveTest extends GraalCompilerTest {
  37 
  38     public static int loopFrequencySnippet(int arg) {
  39         int x = arg;
  40         while (GraalDirectives.injectIterationCount(128, x > 1)) {
  41             GraalDirectives.controlFlowAnchor(); // prevent loop peeling or unrolling
  42             if (x % 2 == 0) {
  43                 x /= 2;
  44             } else {
  45                 x = 3 * x + 1;
  46             }
  47         }
  48         return x;
  49     }
  50 
  51     @Test
  52     public void testLoopFrequency() {
  53         test("loopFrequencySnippet", 7);
  54     }
  55 
  56     @Override
  57     protected boolean checkLowTierGraph(StructuredGraph graph) {
  58         NodeIterable<LoopBeginNode> loopBeginNodes = graph.getNodes(LoopBeginNode.TYPE);
  59         Assert.assertEquals("LoopBeginNode count", 1, loopBeginNodes.count());
  60 
  61         LoopBeginNode loopBeginNode = loopBeginNodes.first();
  62         Assert.assertEquals("loop frequency of " + loopBeginNode, 128, loopBeginNode.loopFrequency(), 0);
  63 
  64         return true;
  65     }
  66 }