1 /* 2 * Copyright (c) 2010, 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 * @test 26 * @bug 6603011 27 * @summary long/int division by constant 28 * @library /testlibrary 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.io.File; 40 import java.net.URL; 41 import java.net.URLClassLoader; 42 import jdk.test.lib.Utils; 43 44 class s { 45 static int divi(int dividend, int divisor) { return dividend / divisor; } 46 static int modi(int dividend, int divisor) { return dividend % divisor; } 47 static long divl(long dividend, long divisor) { return dividend / divisor; } 48 static long modl(long dividend, long divisor) { return dividend % divisor; } 49 } 50 51 public class Test implements Runnable { 52 // Report verbose messages on failure; turn off to suppress 53 // too much output with gross numbers of failures. 54 static final boolean VERBOSE = true; 55 56 // Initailize DIVISOR so that it is final in this class. 57 static final int DIVISOR; 58 static { 59 int value = 0; 60 try { 61 value = Integer.decode(System.getProperty("divisor")); 62 } catch (Throwable e) { 63 } 64 DIVISOR = value; 65 } 66 67 // The methods of interest. We want the JIT to compile these 68 // and convert the divide into a multiply. 69 public int divbyI (int dividend) { return dividend / DIVISOR; } 70 public int modbyI (int dividend) { return dividend % DIVISOR; } 71 public long divbyL (long dividend) { return dividend / DIVISOR; } 72 public long modbyL (long dividend) { return dividend % DIVISOR; } 73 74 public int divisor() { return DIVISOR; } 75 76 public boolean checkI (int dividend) { 77 int quo = divbyI(dividend); 78 int rem = modbyI(dividend); 79 int quo0 = s.divi(dividend, divisor()); 80 int rem0 = s.modi(dividend, divisor()); 81 82 if (quo != quo0 || rem != rem0) { 83 if (VERBOSE) { 84 System.out.println("Computed: " + dividend + " / " + divisor() + " = " + 85 quo + ", " + dividend + " % " + divisor() + " = " + rem ); 86 System.out.println("expected: " + dividend + " / " + divisor() + " = " + 87 quo0 + ", " + dividend + " % " + divisor() + " = " + rem0); 88 // Report sign of rem failure 89 if (rem != 0 && (rem ^ dividend) < 0) { 90 System.out.println(" rem & dividend have different signs"); 91 } 92 // Report range of rem failure 93 if (java.lang.Math.abs(rem) >= java.lang.Math.abs(divisor())) { 94 System.out.println(" remainder out of range"); 95 } 96 // Report quo/rem identity relationship failure 97 if ((quo * divisor()) + rem != dividend) { 98 System.out.println(" quotien/remainder invariant broken"); 99 } 100 } 101 return false; 102 } 103 return true; 104 } 105 106 public boolean checkL (long dividend) { 107 long quo = divbyL(dividend); 108 long rem = modbyL(dividend); 109 long quo0 = s.divl(dividend, divisor()); 110 long rem0 = s.modl(dividend, divisor()); 111 112 if (quo != quo0 || rem != rem0) { 113 if (VERBOSE) { 114 System.out.println("Computed: " + dividend + " / " + divisor() + " = " + 115 quo + ", " + dividend + " % " + divisor() + " = " + rem ); 116 System.out.println("expected: " + dividend + " / " + divisor() + " = " + 117 quo0 + ", " + dividend + " % " + divisor() + " = " + rem0); 118 // Report sign of rem failure 119 if (rem != 0 && (rem ^ dividend) < 0) { 120 System.out.println(" rem & dividend have different signs"); 121 } 122 // Report range of rem failure 123 if (java.lang.Math.abs(rem) >= java.lang.Math.abs(divisor())) { 124 System.out.println(" remainder out of range"); 125 } 126 // Report quo/rem identity relationship failure 127 if ((quo * divisor()) + rem != dividend) { 128 System.out.println(" (" + quo + " * " + divisor() + ") + " + rem + " != " 129 + dividend); 130 } 131 } 132 return false; 133 } 134 return true; 135 } 136 137 public void run() { 138 // Don't try to divide by zero 139 if (divisor() == 0) return; 140 141 // Range of dividends to check. Try dividends from start to end 142 // inclusive, as well as variations on those values as shifted 143 // left. 144 int start = -1024; 145 int end = 1024; 146 147 // Test int division using a variety of dividends. 148 int wrong = 0; 149 int total = 0; 150 151 outerloop: 152 for (int i = start; i <= end; i++) { 153 for (int s = 0; s < 32; s += 4) { 154 total++; 155 int dividend = i << s; 156 if (!checkI(dividend)) { 157 wrong++; 158 // Stop on the first failure 159 // break outerloop; 160 } 161 } 162 } 163 if (wrong > 0) { 164 System.out.println("divisor " + divisor() + ": " + 165 wrong + "/" + total + " wrong int divisions"); 166 } 167 168 // Test long division using a variety of dividends. 169 wrong = 0; 170 total = 0; 171 172 outerloop: 173 for (int i = start; i <= end; i++) { 174 for (int s = 0; s < 64; s += 4) { 175 total++; 176 long dividend = ((long)i) << s; 177 if (!checkL(dividend)) { 178 wrong++; 179 // Stop on the first failure 180 // break outerloop; 181 } 182 } 183 } 184 if (wrong > 0) { 185 System.out.println("divisor " + divisor() + ": " + 186 wrong + "/" + total + " wrong long divisions"); 187 } 188 189 } 190 191 // Reload this class with the "divisor" property set to the input parameter. 192 // This allows the JIT to see q.DIVISOR as a final constant, and change 193 // any divisions or mod operations into multiplies. 194 public static void test_divisor(int divisor, 195 ClassLoader apploader) throws Exception { 196 System.setProperty("divisor", "" + divisor); 197 ClassLoader loader 198 = Utils.getTestClassPathURLClassLoader(apploader.getParent()); 199 Class c = loader.loadClass("Test"); 200 Runnable r = (Runnable)c.newInstance(); 201 r.run(); 202 } 203 204 public static void main(String[] args) throws Exception { 205 Class cl = Class.forName("Test"); 206 ClassLoader apploader = cl.getClassLoader(); 207 208 209 // Test every divisor between -100 and 100. 210 for (int i = -100; i <= 100; i++) { 211 test_divisor(i, apploader); 212 } 213 214 // Try a few divisors outside the typical range. 215 // The values below have been observed in rt.jar. 216 test_divisor(101, apploader); 217 test_divisor(400, apploader); 218 test_divisor(1000, apploader); 219 test_divisor(3600, apploader); 220 test_divisor(9973, apploader); 221 test_divisor(86400, apploader); 222 test_divisor(1000000, apploader); 223 } 224 225 }