1 /* 2 * Copyright (c) 2010, 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("Computed: " + dividend + " / " + divisor() + " = " + 112 quo + ", " + dividend + " % " + divisor() + " = " + rem ); 113 System.out.println("expected: " + dividend + " / " + divisor() + " = " + 114 quo0 + ", " + dividend + " % " + divisor() + " = " + rem0); 115 // Report sign of rem failure 116 if (rem != 0 && (rem ^ dividend) < 0) { 117 System.out.println(" rem & dividend have different signs"); 118 } 119 // Report range of rem failure 120 if (java.lang.Math.abs(rem) >= java.lang.Math.abs(divisor())) { 121 System.out.println(" remainder out of range"); 122 } 123 // Report quo/rem identity relationship failure 124 if ((quo * divisor()) + rem != dividend) { 125 System.out.println(" (" + quo + " * " + divisor() + ") + " + rem + " != " 126 + dividend); 127 } 128 } 129 return false; 130 } 131 return true; 132 } 133 134 public void run() { 135 // Don't try to divide by zero 136 if (divisor() == 0) return; 137 138 // Range of dividends to check. Try dividends from start to end 139 // inclusive, as well as variations on those values as shifted 140 // left. 141 int start = -1024; 142 int end = 1024; 143 144 // Test int division using a variety of dividends. 145 int wrong = 0; 146 int total = 0; 147 148 outerloop: 149 for (int i = start; i <= end; i++) { 150 for (int s = 0; s < 32; s += 4) { 151 total++; 152 int dividend = i << s; 153 if (!checkI(dividend)) { 154 wrong++; 155 // Stop on the first failure 156 // break outerloop; 157 } 158 } 159 } 160 if (wrong > 0) { 161 System.out.println("divisor " + divisor() + ": " + 162 wrong + "/" + total + " wrong int divisions"); 163 } 164 165 // Test long division using a variety of dividends. 166 wrong = 0; 167 total = 0; 168 169 outerloop: 170 for (int i = start; i <= end; i++) { 171 for (int s = 0; s < 64; s += 4) { 172 total++; 173 long dividend = ((long)i) << s; 174 if (!checkL(dividend)) { 175 wrong++; 176 // Stop on the first failure 177 // break outerloop; 178 } 179 } 180 } 181 if (wrong > 0) { 182 System.out.println("divisor " + divisor() + ": " + 183 wrong + "/" + total + " wrong long divisions"); 184 } 185 186 } 187 188 // Reload this class with the "divisor" property set to the input parameter. 189 // This allows the JIT to see q.DIVISOR as a final constant, and change 190 // any divisions or mod operations into multiplies. 191 public static void test_divisor(int divisor, 192 URLClassLoader apploader) throws Exception { 193 System.setProperty("divisor", "" + divisor); 194 ClassLoader loader = new URLClassLoader(apploader.getURLs(), 195 apploader.getParent()); 196 Class c = loader.loadClass("Test"); 197 Runnable r = (Runnable)c.newInstance(); 198 r.run(); 199 } 200 201 public static void main(String[] args) throws Exception { 202 Class cl = Class.forName("Test"); 203 URLClassLoader apploader = (URLClassLoader)cl.getClassLoader(); 204 205 206 // Test every divisor between -100 and 100. 207 for (int i = -100; i <= 100; i++) { 208 test_divisor(i, apploader); 209 } 210 211 // Try a few divisors outside the typical range. 212 // The values below have been observed in rt.jar. 213 test_divisor(101, apploader); 214 test_divisor(400, apploader); 215 test_divisor(1000, apploader); 216 test_divisor(3600, apploader); 217 test_divisor(9973, apploader); 218 test_divisor(86400, apploader); 219 test_divisor(1000000, apploader); 220 } 221 222 }