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comparison test/compiler/loopopts/TestLogSum.java @ 17985:4077c61b03a0

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8046516: Segmentation fault in JVM (easily reproducible) Summary: Place new nodes on the previous loop exit in reorg_offsets(). Reviewed-by: roland
author kvn
date Thu, 12 Jun 2014 10:15:43 -0700
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17984:22146594cd5a 17985:4077c61b03a0
1 /*
2 * Copyright (c) 2014, 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 8046516
27 * @summary Segmentation fault in JVM (easily reproducible)
28 * @run main/othervm -XX:-TieredCompilation -Xbatch TestLogSum
29 * @author jackkamm@gmail.com
30 */
31
32 import java.util.Arrays;
33 import java.util.HashMap;
34 import java.util.List;
35 import java.util.Map;
36 public class TestLogSum {
37 public static void main(String[] args) {
38 double sum;
39
40 for (int i = 0; i < 6; i++) {
41 for (int n = 2; n < 30; n++) {
42 for (int j = 1; j <= n; j++) {
43 for (int k = 1; k <= j; k++) {
44 // System.out.println(computeSum(k, j));
45 sum = computeSum(k, j);
46 }
47 }
48 }
49 }
50 }
51
52 private static Map<List<Integer>, Double> cache = new HashMap<List<Integer>, Double>();
53 public static double computeSum(int x, int y) {
54 List<Integer> key = Arrays.asList(new Integer[] {x, y});
55
56 if (!cache.containsKey(key)) {
57
58 // explicitly creating/updating a double[] array, instead of using the LogSumArray wrapper object, will prevent the error
59 LogSumArray toReturn = new LogSumArray(x);
60
61 // changing loop indices will prevent the error
62 // in particular, for(z=0; z<x-1; z++), and then using z+1 in place of z, will not produce error
63 for (int z = 1; z < x+1; z++) {
64 double logSummand = Math.log(z + x + y);
65 toReturn.addLogSummand(logSummand);
66 }
67
68 // returning the value here without cacheing it will prevent the segfault
69 cache.put(key, toReturn.retrieveLogSum());
70 }
71 return cache.get(key);
72 }
73
74 /*
75 * Given a bunch of logarithms log(X),log(Y),log(Z),...
76 * This class is used to compute the log of the sum, log(X+Y+Z+...)
77 */
78 private static class LogSumArray {
79 private double[] logSummandArray;
80 private int currSize;
81
82 private double maxLogSummand;
83
84 public LogSumArray(int maxEntries) {
85 this.logSummandArray = new double[maxEntries];
86
87 this.currSize = 0;
88 this.maxLogSummand = Double.NEGATIVE_INFINITY;
89 }
90
91 public void addLogSummand(double logSummand) {
92 logSummandArray[currSize] = logSummand;
93 currSize++;
94 // removing this line will prevent the error
95 maxLogSummand = Math.max(maxLogSummand, logSummand);
96 }
97
98 public double retrieveLogSum() {
99 if (maxLogSummand == Double.NEGATIVE_INFINITY) return Double.NEGATIVE_INFINITY;
100
101 assert currSize <= logSummandArray.length;
102
103 double factorSum = 0;
104 for (int i = 0; i < currSize; i++) {
105 factorSum += Math.exp(logSummandArray[i] - maxLogSummand);
106 }
107
108 return Math.log(factorSum) + maxLogSummand;
109 }
110 }
111 }