1 /* 2 * Copyright (c) 2009, 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 * @test 26 * @bug 6603011 27 * @summary long/int division by constant 28 * 29 * @run main/othervm -Xcomp -Xbatch -XX:-Inline Test 30 */ 31 32 // 33 // -XX:-Inline is essential to this test so that verification functions 34 // divi, modi, divl and modl generate "plain" divides. 35 // -Xcomp -Xbatch are also useful to ensure the full range of 36 // dividend and divisor combinations are tested 37 // 38 39 import java.net.*; 40 41 class s { 42 static int divi(int dividend, int divisor) { return dividend / divisor; } 43 static int modi(int dividend, int divisor) { return dividend % divisor; } 44 static long divl(long dividend, long divisor) { return dividend / divisor; } 45 static long modl(long dividend, long divisor) { return dividend % divisor; } 46 } 47 48 public class Test implements Runnable { 49 // Report verbose messages on failure; turn off to suppress 50 // too much output with gross numbers of failures. 51 static final boolean VERBOSE = true; 52 53 // Initailize DIVISOR so that it is final in this class. 54 static final int DIVISOR; 55 static { 56 int value = 0; 57 try { 58 value = Integer.decode(System.getProperty("divisor")); 59 } catch (Throwable e) { 60 } 61 DIVISOR = value; 62 } 63 64 // The methods of interest. We want the JIT to compile these 65 // and convert the divide into a multiply. 66 public int divbyI (int dividend) { return dividend / DIVISOR; } 67 public int modbyI (int dividend) { return dividend % DIVISOR; } 68 public long divbyL (long dividend) { return dividend / DIVISOR; } 69 public long modbyL (long dividend) { return dividend % DIVISOR; } 70 71 public int divisor() { return DIVISOR; } 72 73 public boolean checkI (int dividend) { 74 int quo = divbyI(dividend); 75 int rem = modbyI(dividend); 76 int quo0 = s.divi(dividend, divisor()); 77 int rem0 = s.modi(dividend, divisor()); 78 79 if (quo != quo0 || rem != rem0) { 80 if (VERBOSE) { 81 System.out.println("Computed: " + dividend + " / " + divisor() + " = " + 82 quo + ", " + dividend + " % " + divisor() + " = " + rem ); 83 System.out.println("expected: " + dividend + " / " + divisor() + " = " + 84 quo0 + ", " + dividend + " % " + divisor() + " = " + rem0); 85 // Report sign of rem failure 86 if (rem != 0 && (rem ^ dividend) < 0) { 87 System.out.println(" rem & dividend have different signs"); 88 } 89 // Report range of rem failure 90 if (java.lang.Math.abs(rem) >= java.lang.Math.abs(divisor())) { 91 System.out.println(" remainder out of range"); 92 } 93 // Report quo/rem identity relationship failure 94 if ((quo * divisor()) + rem != dividend) { 95 System.out.println(" quotien/remainder invariant broken"); 96 } 97 } 98 return false; 99 } 100 return true; 101 } 102 103 public boolean checkL (long dividend) { 104 long quo = divbyL(dividend); 105 long rem = modbyL(dividend); 106 long quo0 = s.divl(dividend, divisor()); 107 long rem0 = s.modl(dividend, divisor()); 108 109 if (quo != quo0 || rem != rem0) { 110 if (VERBOSE) { 111 System.out.println(" " + dividend + " / " + divisor() + " = " + 112 quo + ", " + dividend + " % " + divisor() + " = " + rem); 113 // Report sign of rem failure 114 if (rem != 0 && (rem ^ dividend) < 0) { 115 System.out.println(" rem & dividend have different signs"); 116 } 117 // Report range of rem failure 118 if (java.lang.Math.abs(rem) >= java.lang.Math.abs(divisor())) { 119 System.out.println(" remainder out of range"); 120 } 121 // Report quo/rem identity relationship failure 122 if ((quo * divisor()) + rem != dividend) { 123 System.out.println(" (" + quo + " * " + divisor() + ") + " + rem + " != " 124 + dividend); 125 } 126 } 127 return false; 128 } 129 return true; 130 } 131 132 public void run() { 133 // Don't try to divide by zero 134 if (divisor() == 0) return; 135 136 // Range of dividends to check. Try dividends from start to end 137 // inclusive, as well as variations on those values as shifted 138 // left. 139 int start = -1024; 140 int end = 1024; 141 142 // Test int division using a variety of dividends. 143 int wrong = 0; 144 int total = 0; 145 146 outerloop: 147 for (int i = start; i <= end; i++) { 148 for (int s = 0; s < 32; s += 4) { 149 total++; 150 int dividend = i << s; 151 if (!checkI(dividend)) { 152 wrong++; 153 // Stop on the first failure 154 // break outerloop; 155 } 156 } 157 } 158 if (wrong > 0) { 159 System.out.println("divisor " + divisor() + ": " + 160 wrong + "/" + total + " wrong int divisions"); 161 } 162 163 // Test long division using a variety of dividends. 164 wrong = 0; 165 total = 0; 166 167 outerloop: 168 for (int i = start; i <= end; i++) { 169 for (int s = 0; s < 64; s += 4) { 170 total++; 171 long dividend = i << s; 172 if (!checkL(dividend)) { 173 wrong++; 174 // Stop on the first failure 175 // break outerloop; 176 } 177 } 178 } 179 if (wrong > 0) { 180 System.out.println("divisor " + divisor() + ": " + 181 wrong + "/" + total + " wrong long divisions"); 182 } 183 184 } 185 186 // Reload this class with the "divisor" property set to the input parameter. 187 // This allows the JIT to see q.DIVISOR as a final constant, and change 188 // any divisions or mod operations into multiplies. 189 public static void test_divisor(int divisor, 190 URLClassLoader apploader) throws Exception { 191 System.setProperty("divisor", "" + divisor); 192 ClassLoader loader = new URLClassLoader(apploader.getURLs(), 193 apploader.getParent()); 194 Class c = loader.loadClass("Test"); 195 Runnable r = (Runnable)c.newInstance(); 196 r.run(); 197 } 198 199 public static void main(String[] args) throws Exception { 200 Class cl = Class.forName("Test"); 201 URLClassLoader apploader = (URLClassLoader)cl.getClassLoader(); 202 203 204 // Test every divisor between -100 and 100. 205 for (int i = -100; i <= 100; i++) { 206 test_divisor(i, apploader); 207 } 208 209 // Try a few divisors outside the typical range. 210 // The values below have been observed in rt.jar. 211 test_divisor(101, apploader); 212 test_divisor(400, apploader); 213 test_divisor(1000, apploader); 214 test_divisor(3600, apploader); 215 test_divisor(9973, apploader); 216 test_divisor(86400, apploader); 217 test_divisor(1000000, apploader); 218 } 219 220 }