[Bug c/41805] New: possible LTO termination bug

[Bug c/41805] New: possible LTO termination bug

[regehr at cs dot utah dot edu]

Using r153474 with LTO, the compilation units below appear to be improperly
turned into a terminating executable.

regehr@john-home:~$ current-gcc -g -Wall -O3 -flto -c rnd_output0.c
regehr@john-home:~$ current-gcc -g -Wall -O3 -flto -c rnd_output1.c
regehr@john-home:~$ current-gcc -g -Wall -O3 -flto rnd_output1.o rnd_output0.o
-o rand 
regehr@john-home:~$ ./rand
Done
regehr@john-home:~$ 
regehr@john-home:~$ cat rnd_output0.c
#include <assert.h>
#include <stdio.h>

int func_5();

int i = 0;

int func_2()
{
    func_5();
    assert(i == 0);
    assert(i == 0);
    assert(i == 0);
    assert(i == 0);
    assert(i == 0);
    assert(i == 0);
    assert(i == 0);
    return 0;
}

int func_1(int p)
{
    func_2();
    return 0;
}

int main(void)
{
    func_1(func_2());
    printf ("Done\n");
    return 0;
}
regehr@john-home:~$ cat rnd_output1.c
int func_5()
{
    while(1)
      ;
    return 0;
}


-- 
           Summary: possible LTO termination bug
           Product: gcc
           Version: unknown
            Status: UNCONFIRMED
          Severity: normal
          Priority: P3
         Component: c
        AssignedTo: unassigned at gcc dot gnu dot org
        ReportedBy: regehr at cs dot utah dot edu
 GCC build triplet: i686-pc-linux-gnu
  GCC host triplet: i686-pc-linux-gnu
GCC target triplet: i686-pc-linux-gnu


http://gcc.gnu.org/bugzilla/show_bug.cgi?id=41805

[Bug c/41805] possible LTO termination bug

[regehr at cs dot utah dot edu]

------- Comment #1 from regehr at cs dot utah dot edu  2009-10-23 02:50 -------
Forgot to add gcc details:

regehr@john-home:~$ current-gcc -v
Using built-in specs.
COLLECT_GCC=current-gcc
COLLECT_LTO_WRAPPER=/home/regehr/z/tmp/gcc-r153474-install/libexec/gcc/i686-pc-linux-gnu/4.5.0/lto-wrapper
Target: i686-pc-linux-gnu
Configured with: ../configure --with-libelf=/usr/local --enable-lto
--prefix=/home/regehr/z/tmp/gcc-r153474-install --program-prefix=r153474-
--enable-languages=c,c++
Thread model: posix
gcc version 4.5.0 20091022 (experimental) (GCC) 


-- 


http://gcc.gnu.org/bugzilla/show_bug.cgi?id=41805

[Bug middle-end/41805] possible LTO termination bug

[pinskia at gcc dot gnu dot org]

------- Comment #2 from pinskia at gcc dot gnu dot org  2009-10-23 02:56 -------
Sounds like pure/const pass is messing up.


-- 

pinskia at gcc dot gnu dot org changed:

           What    |Removed                     |Added
----------------------------------------------------------------------------
                 CC|                            |hubicka at gcc dot gnu dot
                   |                            |org
          Component|c                           |middle-end
           Keywords|                            |wrong-code
            Version|unknown                     |4.5.0


http://gcc.gnu.org/bugzilla/show_bug.cgi?id=41805

[Bug middle-end/41805] possible LTO termination bug

[rguenth at gcc dot gnu dot org]

------- Comment #3 from rguenth at gcc dot gnu dot org  2009-10-23 10:04 -------
It is RTL expansion that drops the calls to func_2 () from main.


-- 

rguenth at gcc dot gnu dot org changed:

           What    |Removed                     |Added
----------------------------------------------------------------------------
             Status|UNCONFIRMED                 |NEW
     Ever Confirmed|0                           |1
   Last reconfirmed|0000-00-00 00:00:00         |2009-10-23 10:04:23
               date|                            |


http://gcc.gnu.org/bugzilla/show_bug.cgi?id=41805

[Bug middle-end/41805] possible LTO termination bug

[rguenth at gcc dot gnu dot org]

------- Comment #4 from rguenth at gcc dot gnu dot org  2009-10-23 10:17 -------
I have a patch.


-- 

rguenth at gcc dot gnu dot org changed:

           What    |Removed                     |Added
----------------------------------------------------------------------------
         AssignedTo|unassigned at gcc dot gnu   |rguenth at gcc dot gnu dot
                   |dot org                     |org
             Status|NEW                         |ASSIGNED
   Last reconfirmed|2009-10-23 10:04:23         |2009-10-23 10:17:09
               date|                            |


http://gcc.gnu.org/bugzilla/show_bug.cgi?id=41805

[Bug middle-end/41805] possible LTO termination bug

[rguenth at gcc dot gnu dot org]

------- Comment #5 from rguenth at gcc dot gnu dot org  2009-10-23 10:20 -------
Non-LTO testcase:

void __attribute__((noinline))
foo (void)
{
  while (1)
    ;
}

int main()
{
  foo ();
  return 0;
}


-- 


http://gcc.gnu.org/bugzilla/show_bug.cgi?id=41805

[Bug middle-end/41805] possible LTO termination bug

[rguenth at gcc dot gnu dot org]

------- Comment #6 from rguenth at gcc dot gnu dot org  2009-10-23 12:01 -------
Subject: Bug 41805

Author: rguenth
Date: Fri Oct 23 12:01:21 2009
New Revision: 153495

URL: http://gcc.gnu.org/viewcvs?root=gcc&view=rev&rev=153495
Log:
2009-10-23  Richard Guenther  <rguenther@suse.de>

        PR middle-end/41805
        * cfgexpand.c (expand_call_stmt): Use gimple_has_side_effects and
        gimple_call_nothrow_p.

Modified:
    trunk/gcc/ChangeLog
    trunk/gcc/cfgexpand.c


-- 


http://gcc.gnu.org/bugzilla/show_bug.cgi?id=41805

[Bug middle-end/41805] possible LTO termination bug

[rguenth at gcc dot gnu dot org]

------- Comment #7 from rguenth at gcc dot gnu dot org  2009-10-23 13:16 -------
Fixed.


-- 

rguenth at gcc dot gnu dot org changed:

           What    |Removed                     |Added
----------------------------------------------------------------------------
             Status|ASSIGNED                    |RESOLVED
         Resolution|                            |FIXED
   Target Milestone|---                         |4.5.0


http://gcc.gnu.org/bugzilla/show_bug.cgi?id=41805