1 /* 2 * Copyright (c) 2014 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.openjdk.bench.vm.compiler; 24 25 import org.openjdk.jmh.annotations.Benchmark; 26 import org.openjdk.jmh.annotations.BenchmarkMode; 27 import org.openjdk.jmh.annotations.Mode; 28 import org.openjdk.jmh.annotations.OutputTimeUnit; 29 import org.openjdk.jmh.annotations.Scope; 30 import org.openjdk.jmh.annotations.Setup; 31 import org.openjdk.jmh.annotations.State; 32 33 import java.util.concurrent.TimeUnit; 34 35 /** 36 * Benchmark measuring the gain of removing array bound checks in various cases 37 */ 38 @BenchmarkMode(Mode.AverageTime) 39 @OutputTimeUnit(TimeUnit.NANOSECONDS) 40 @State(Scope.Thread) 41 public class ArrayBoundCheckRemoval { 42 43 private int[] a; 44 private int j, u, v; 45 46 @Setup 47 public void setup() { 48 a = new int[200]; 49 } 50 51 @Benchmark 52 public int[] testForLoopAccess() throws Exception { 53 int[] a = this.a; 54 for (int i = 0; i < a.length; i++) { 55 a[i] = i; 56 } 57 return a; 58 } 59 60 @Benchmark 61 public int[] testBubblesortStripped() throws Exception { 62 int[] a = this.a; 63 int limit = a.length; 64 int st = -1; 65 66 while (st < limit) { 67 st++; 68 limit--; 69 for (j = st; j < limit; j++) { 70 u = a[j]; 71 v = a[j + 1]; 72 } 73 } 74 return a; 75 } 76 77 @Benchmark 78 public int[] testBubblesort() throws Exception { 79 int[] a = this.a; 80 int j1; 81 int limit = a.length; 82 int st = -1; 83 while (st < limit) { 84 boolean flipped = false; 85 st++; 86 limit--; 87 for (j1 = st; j1 < limit; j1++) { 88 if (a[j1] > a[j1 + 1]) { 89 int T = a[j1]; 90 a[j1] = a[j1 + 1]; 91 a[j1 + 1] = T; 92 flipped = true; 93 } 94 } 95 if (!flipped) { 96 return a; 97 } 98 flipped = false; 99 for (j1 = limit; --j1 >= st; ) { 100 if (a[j1] > a[j1 + 1]) { 101 int T = a[j1]; 102 a[j1] = a[j1 + 1]; 103 a[j1 + 1] = T; 104 flipped = true; 105 } 106 } 107 if (!flipped) { 108 return a; 109 } 110 } 111 return a; 112 } 113 114 }