[Bug c/19873] New: odd behaviour compiling XaoS

[Bug c/19873] New: odd behaviour compiling XaoS

[kovzol at math dot u-szeged dot hu]

The current source (CVS or 3.1.1, same) of XaoS (http://xaos.sf.net), if you
compile it and run bin/xaos, gives a segmentation fault if you press the button
B twice (setting perturbation on/off). Now if I add the following line to
src/ui-hlp/menu.c in the end of uih_persw():

printf("");

there will be no segfault. Do you think this is a gcc problem? (However,
other statements may solve the problem, not only printf(). I also tried sync()
with success.) I'm using  SuSE 9.1 (but the same problem occurs on 9.0, too,
with an earlier gcc version).

However, I'm not an expert in C programming. But this seems to be odd that a
virtually uneffective printf("") can solve a segfault problem. I never
experienced such an odd behaviour earlier in gcc.

-- 
           Summary: odd behaviour compiling XaoS
           Product: gcc
           Version: 3.3.3
            Status: UNCONFIRMED
          Severity: normal
          Priority: P2
         Component: c
        AssignedTo: unassigned at gcc dot gnu dot org
        ReportedBy: kovzol at math dot u-szeged dot hu
                CC: gcc-bugs at gcc dot gnu dot org
  GCC host triplet: (uname -a) Linux d7017 2.6.4-54.5-default #1 Fri May 7
                    21:43:10
GCC target triplet: (gcc --version) gcc (GCC) 3.3.3 (SuSE Linux)


http://gcc.gnu.org/bugzilla/show_bug.cgi?id=19873

[Bug c/19873] odd behaviour compiling XaoS

[falk at debian dot org]

------- Additional Comments From falk at debian dot org  2005-02-10 13:16 -------
(In reply to comment #0)
> The current source (CVS or 3.1.1, same) of XaoS (http://xaos.sf.net), if you
> compile it and run bin/xaos, gives a segmentation fault if you press the button
> B twice (setting perturbation on/off). Now if I add the following line to
> src/ui-hlp/menu.c in the end of uih_persw():
> 
> printf("");
> 
> there will be no segfault. Do you think this is a gcc problem?

That doesn't really give any indication. In my experience, it is more likely
not to be a bug in gcc. We cannot do anything about this until you come up with
a test case...

-- 
           What    |Removed                     |Added
----------------------------------------------------------------------------
             Status|UNCONFIRMED                 |WAITING


http://gcc.gnu.org/bugzilla/show_bug.cgi?id=19873

[Bug c/19873] odd behaviour compiling XaoS

[kovzol at math dot u-szeged dot hu]

------- Additional Comments From kovzol at math dot u-szeged dot hu  2005-02-10 13:21 -------
OK, I see that this is not really a good bug report, I know.

Now I tried the same compilation under gcc-2.95.3 (SuSE 8.0, x86) and the same 
source works perfectly.

-- 


http://gcc.gnu.org/bugzilla/show_bug.cgi?id=19873

[Bug middle-end/19873] odd behaviour compiling XaoS

[pinskia at gcc dot gnu dot org]

------- Additional Comments From pinskia at gcc dot gnu dot org  2005-02-10 15:25 -------
(In reply to comment #2)
> OK, I see that this is not really a good bug report, I know.
> 
> Now I tried the same compilation under gcc-2.95.3 (SuSE 8.0, x86) and the same 
> source works perfectly.

Could you try -fno-strict-aliasing, if that works then the bug is the code and not in gcc.


-- 
           What    |Removed                     |Added
----------------------------------------------------------------------------
          Component|c                           |middle-end


http://gcc.gnu.org/bugzilla/show_bug.cgi?id=19873

[Bug middle-end/19873] odd behaviour compiling XaoS

[pinskia at gcc dot gnu dot org]

------- Additional Comments From pinskia at gcc dot gnu dot org  2005-05-12 01:23 -------
No feedback in 3 months.

-- 
           What    |Removed                     |Added
----------------------------------------------------------------------------
             Status|WAITING                     |RESOLVED
         Resolution|                            |INVALID


http://gcc.gnu.org/bugzilla/show_bug.cgi?id=19873