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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 /test/lib
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
41package compiler.c2;
42
43import jdk.test.lib.Utils;
44
45public 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}
226