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