[Bug java/31842] New: r124338 causes java Divide_1 and pr6388 to fail

[Bug java/31842] New: r124338 causes java Divide_1 and pr6388 to fail

[daney at gcc dot gnu dot org]

Examining testresults:
 http://gcc.gnu.org/ml/gcc-testresults/2007-05/msg00045.html
and
 http://gcc.gnu.org/ml/gcc-testresults/2007-05/msg00102.html

Leads us to the conclusion the the patch r124338 causes regressions in the java
testsuite for Divide_1 and pr6388 on the 4.2 branch.  The corresponding trunk
patch seems to break the trunk in a similar manner.

I am bootstrapping before and after the patch to prove to myself that it is
culpable


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           Summary: r124338 causes java Divide_1 and pr6388 to fail
           Product: gcc
           Version: 4.2.0
            Status: UNCONFIRMED
          Severity: normal
          Priority: P3
         Component: java
        AssignedTo: unassigned at gcc dot gnu dot org
        ReportedBy: daney at gcc dot gnu dot org
 GCC build triplet: x86_64-pc-linux-gnu
  GCC host triplet: x86_64-pc-linux-gnu
GCC target triplet: x86_64-pc-linux-gnu


http://gcc.gnu.org/bugzilla/show_bug.cgi?id=31842

[Bug java/31842] [4.2/4.3 Regression] r124338 causes java Divide_1 and pr6388 to fail

[pinskia at gcc dot gnu dot org]

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pinskia at gcc dot gnu dot org changed:

           What    |Removed                     |Added
----------------------------------------------------------------------------
           Severity|normal                      |blocker
           Keywords|                            |wrong-code
            Summary|r124338 causes java Divide_1|[4.2/4.3 Regression] r124338
                   |and pr6388 to fail          |causes java Divide_1 and
                   |                            |pr6388 to fail
   Target Milestone|---                         |4.2.0


http://gcc.gnu.org/bugzilla/show_bug.cgi?id=31842

[Bug java/31842] [4.2/4.3 Regression] r124338 causes java Divide_1 and pr6388 to fail

[daney at gcc dot gnu dot org]

------- Comment #1 from daney at gcc dot gnu dot org  2007-05-07 04:23 -------
I just finished bootstrapping and testing r124337 and r124338 on
x86_64-pc-linux-gnu (FC6). Not surprisingly, this verifies that r124338 causes
the regression.


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http://gcc.gnu.org/bugzilla/show_bug.cgi?id=31842

[Bug java/31842] [4.2/4.3 Regression] r124338 causes java Divide_1 and pr6388 to fail

[ian at airs dot com]

------- Comment #2 from ian at airs dot com  2007-05-07 19:03 -------
Created an attachment (id=13523)
 --> (http://gcc.gnu.org/bugzilla/attachment.cgi?id=13523&action=view)
Patch

The bug is that some C++ code in libjava assumes that signed overflow is
defined.  This is not true for C++.

I'm testing this patch now on 4.2 branch.


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http://gcc.gnu.org/bugzilla/show_bug.cgi?id=31842

[Bug java/31842] [4.2/4.3 Regression] r124338 causes java Divide_1 and pr6388 to fail

[aph at gcc dot gnu dot org]

------- Comment #3 from aph at gcc dot gnu dot org  2007-05-07 19:18 -------
Thanks for the patch.

I could have sworn that we were compiling libgcj's C++ code with -fwrapv in
order give CNI code effectively the same integer overflow behaviour as Java.  I
just checked, and we aren't.  We really should be -- and I presume that would
also fix this bug -- but it's perhaps safer to apply this special-case patch.


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http://gcc.gnu.org/bugzilla/show_bug.cgi?id=31842

[Bug java/31842] [4.2/4.3 Regression] r124338 causes java Divide_1 and pr6388 to fail

[daney at gcc dot gnu dot org]

------- Comment #4 from daney at gcc dot gnu dot org  2007-05-07 20:14 -------
(In reply to comment #3)
> Thanks for the patch.
> 
> I could have sworn that we were compiling libgcj's C++ code with -fwrapv in
> order give CNI code effectively the same integer overflow behaviour as Java.  I
> just checked, and we aren't.  We really should be -- and I presume that would
> also fix this bug -- but it's perhaps safer to apply this special-case patch.

There are pluses and minuses to adding -fwrapv.

On the plus side, this bug would not have been uncovered (arguably it would not
even be a bug).

On the minus side CNI code ceases to be C++, but has special non-standard
wrapping semantics.


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http://gcc.gnu.org/bugzilla/show_bug.cgi?id=31842

[Bug java/31842] [4.2/4.3 Regression] r124338 causes java Divide_1 and pr6388 to fail

[ian at gcc dot gnu dot org]

------- Comment #5 from ian at gcc dot gnu dot org  2007-05-08 01:29 -------
Subject: Bug 31842

Author: ian
Date: Tue May  8 00:29:43 2007
New Revision: 124530

URL: http://gcc.gnu.org/viewcvs?root=gcc&view=rev&rev=124530
Log:
        PR java/31842
        * java/lang/natString.cc (_Jv_FormatInt): Avoid undefined signed
        overflow.

Modified:
    trunk/libjava/ChangeLog
    trunk/libjava/java/lang/natString.cc


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http://gcc.gnu.org/bugzilla/show_bug.cgi?id=31842

[Bug java/31842] [4.2/4.3 Regression] r124338 causes java Divide_1 and pr6388 to fail

[ian at gcc dot gnu dot org]

------- Comment #6 from ian at gcc dot gnu dot org  2007-05-08 01:30 -------
Subject: Bug 31842

Author: ian
Date: Tue May  8 00:30:27 2007
New Revision: 124531

URL: http://gcc.gnu.org/viewcvs?root=gcc&view=rev&rev=124531
Log:
        PR java/31842
        * java/lang/natString.cc (_Jv_FormatInt): Avoid undefined signed
        overflow.

Modified:
    branches/gcc-4_2-branch/libjava/ChangeLog
    branches/gcc-4_2-branch/libjava/java/lang/natString.cc


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http://gcc.gnu.org/bugzilla/show_bug.cgi?id=31842

[Bug java/31842] [4.2/4.3 Regression] r124338 causes java Divide_1 and pr6388 to fail

[ian at airs dot com]

------- Comment #7 from ian at airs dot com  2007-05-08 01:32 -------
Fixed on mainline and 4.2 branch.


-- 

ian at airs dot com changed:

           What    |Removed                     |Added
----------------------------------------------------------------------------
             Status|UNCONFIRMED                 |RESOLVED
         Resolution|                            |FIXED


http://gcc.gnu.org/bugzilla/show_bug.cgi?id=31842

[Bug java/31842] [4.2/4.3 Regression] r124338 causes java Divide_1 and pr6388 to fail

[rguenth at gcc dot gnu dot org]

------- Comment #8 from rguenth at gcc dot gnu dot org  2007-09-09 20:13 -------
Subject: Bug 31842

Author: rguenth
Date: Sun Sep  9 20:12:56 2007
New Revision: 128306

URL: http://gcc.gnu.org/viewcvs?root=gcc&view=rev&rev=128306
Log:
2007-09-09  Richard Guenther  <rguenther@suse.de>

        Backport from mainline:
        2007-05-07  Ian Lance Taylor  <iant@google.com>

        PR java/31842
        * java/lang/natString.cc (_Jv_FormatInt): Avoid undefined signed
        overflow.

Modified:
    branches/gcc-4_1-branch/libjava/ChangeLog
    branches/gcc-4_1-branch/libjava/java/lang/natString.cc


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http://gcc.gnu.org/bugzilla/show_bug.cgi?id=31842