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    23 

    24 /**

    25  * @test

    26  * @bug 6603011

    27  * @summary long/int division by constant

    28  * @modules java.base/jdk.internal.misc

    29  * @library /testlibrary

    30  *

    31  * @run main/othervm -Xcomp -Xbatch -XX:-Inline compiler.c2.Test6603011

    32  */

    33 

    34 //

    35 // -XX:-Inline is essential to this test so that verification functions

    36 //   divi, modi, divl and modl generate "plain" divides.

    37 // -Xcomp -Xbatch are also useful to ensure the full range of

    38 //   dividend and divisor combinations are tested

    39 //

    40 

    41 package compiler.c2;

    42 

    43 import jdk.test.lib.Utils;

    44 

    45 public class Test6603011 implements Runnable {

    46   static class s {

    47     static int  divi(int  dividend, int  divisor) { return dividend / divisor; }

    48     static int  modi(int  dividend, int  divisor) { return dividend % divisor; }

    49     static long divl(long dividend, long divisor) { return dividend / divisor; }

    50     static long modl(long dividend, long divisor) { return dividend % divisor; }

    51   }

    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(Test6603011.class.getName());

   200     Runnable r = (Runnable)c.newInstance();

   201     r.run();

   202   }

   203 

   204   public static void main(String[] args) throws Exception {

   205     Class cl = Test6603011.class;

   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 }