Uploaded image for project: 'JDK'
  1. JDK
  2. JDK-6850611

int / long arithmetic seems to be broken in 1.6.0_14 HotSpot Server VM (Win XP)

    Details

    • Type: Bug
    • Status: Closed
    • Priority: P3
    • Resolution: Duplicate
    • Affects Version/s: 6u14
    • Fix Version/s: None
    • Component/s: hotspot
    • Labels:
    • Subcomponent:
    • CPU:
      x86
    • OS:
      windows_xp

      Description

      FULL PRODUCT VERSION :
      java version "1.6.0_14"
      Java(TM) SE Runtime Environment (build 1.6.0_14-b08)
      Java HotSpot(TM) Server VM (build 14.0-b16, mixed mode)

      The same behavior is also reproducible on
      Linux (32 bit) with 1.6.0_14.

      It is further reproducible with 1.7.0-ea (build 1.7.0-ea-b59) on
      both Win XP (32 bit) and Linux (32 bit).


      FULL OS VERSION :
      Microsoft Windows XP [Version 5.1.2600] (SP3)

      EXTRA RELEVANT SYSTEM CONFIGURATION :
      CPU: Intel T7200 Dual Core @ 2 GHz

      A DESCRIPTION OF THE PROBLEM :

      Summing all ints from Integer.MIN_VALUE up to Integer.MAX_VALUE - 1 into a long variable gives different results when run in the server VM as opposed to the client VM.

      Doing this 10 times gives even 2 different results for the server VM!

      This doesn't happen in the client VM or in interpreted (-Xint) mode.

      (I checked the behavior for the older server VMs: 1.6.0_12, 1.5.0_17 and 1.4.2_17 - all of them deliver the "expected" result shown below)

      THE PROBLEM WAS REPRODUCIBLE WITH -Xint FLAG: No

      THE PROBLEM WAS REPRODUCIBLE WITH -server FLAG: Yes

      STEPS TO FOLLOW TO REPRODUCE THE PROBLEM :
      Run the test case (test.TestCase) with the 1.6.0_14 server VM on Windows XP

      My command line is: "F:\Develop>F:\Java\sun-jdk1.6.0_14\bin\java -server test.TestCase"

      EXPECTED VERSUS ACTUAL BEHAVIOR :
      Expected results:

      sum: -4294967295
      sum: -4294967295
      sum: -4294967295
      sum: -4294967295
      sum: -4294967295
      sum: -4294967295
      sum: -4294967295
      sum: -4294967295
      sum: -4294967295
      sum: -4294967295

      Actual results:

      sum: -32212254615
      sum: -36507221880
      sum: -36507221880
      sum: -36507221880
      sum: -36507221880
      sum: -36507221880
      sum: -36507221880
      sum: -36507221880
      sum: -36507221880
      sum: -36507221880

      Note, the first output is differs from the rest. All of them seem to be wrong.


      REPRODUCIBILITY :
      This bug can be reproduced always.

      ---------- BEGIN SOURCE ----------
      package test;

      public class TestCase {

      public static void main(String[] args) {
      test();
      }

      private static void test() {
      for (int j = 0; j < 10; ++j) {
      long x = 0;
      for (int i = Integer.MIN_VALUE; i < Integer.MAX_VALUE; ++i) {
      x += i;
      }
      System.out.println("sum: " + x);
      }
      }
      }

      ---------- END SOURCE ----------

      CUSTOMER SUBMITTED WORKAROUND :
      None (apart from goin back to 1.6.0 Update 12 where this doesn't happen)

      Release Regression From : 6u13
      The above release value was the last known release where this
      bug was not reproducible. Since then there has been a regression.

        Attachments

          Issue Links

            Activity

              People

              • Assignee:
                cfang Changpeng Fang (Inactive)
                Reporter:
                ndcosta Nelson Dcosta (Inactive)
              • Votes:
                0 Vote for this issue
                Watchers:
                0 Start watching this issue

                Dates

                • Created:
                  Updated:
                  Resolved:
                  Imported:
                  Indexed: