[Bug c/38616] New: Wrong code when -O3 or -O2 used

[Bug c/38616] New: Wrong code when -O3 or -O2 used

[socketpair at gmail dot com]

I'm using generic Ubuntu Intrepid desktop i386 system.
My program:
--------------------
#include <stdio.h> 

int main (void)
{
  char buffer[1024]="";
  sprintf (buffer, "%s", "1234567890abcdefghijklmno");
  printf ("%s\n", buffer);
  return 0;
}
----------
It will print '12345678' if -O2 or -O3 is used. If no optimizations used, it
print full string as in source. If I replace 'char buffer[1024]="";'  with
'char buffer[1024];'  it will work just fine with any optimizations. WTF?
------
mmarkk@mmarkk-desktop:~$ LANG=C gcc -O2 -v zzz2.c
Using built-in specs.
Target: i486-linux-gnu
Configured with: ../src/configure -v --with-pkgversion='Ubuntu 4.3.2-1ubuntu11'
--with-bugurl=file:///usr/share/doc/gcc-4.3/README.Bugs
--enable-languages=c,c++,fortran,objc,obj-c++ --prefix=/usr --enable-shared
--with-system-zlib --libexecdir=/usr/lib --without-included-gettext
--enable-threads=posix --enable-nls --with-gxx-include-dir=/usr/include/c++/4.3
--program-suffix=-4.3 --enable-clocale=gnu --enable-libstdcxx-debug
--enable-objc-gc --enable-mpfr --enable-targets=all --enable-checking=release
--build=i486-linux-gnu --host=i486-linux-gnu --target=i486-linux-gnu
Thread model: posix
gcc version 4.3.2 (Ubuntu 4.3.2-1ubuntu11) 
COLLECT_GCC_OPTIONS='-O2' '-v' '-mtune=generic'
 /usr/lib/gcc/i486-linux-gnu/4.3.2/cc1 -quiet -v zzz2.c -D_FORTIFY_SOURCE=2
-quiet -dumpbase zzz2.c -mtune=generic -auxbase zzz2 -O2 -version
-fstack-protector -o /tmp/ccxjcnkd.s
ignoring nonexistent directory "/usr/local/include/i486-linux-gnu"
ignoring nonexistent directory "/usr/local/include"
ignoring nonexistent directory
"/usr/lib/gcc/i486-linux-gnu/4.3.2/../../../../i486-linux-gnu/include"
ignoring nonexistent directory "/usr/include/i486-linux-gnu"
#include "..." search starts here:
#include <...> search starts here:
 /usr/lib/gcc/i486-linux-gnu/4.3.2/include
 /usr/lib/gcc/i486-linux-gnu/4.3.2/include-fixed
 /usr/include
End of search list.
GNU C (Ubuntu 4.3.2-1ubuntu11) version 4.3.2 (i486-linux-gnu)
        compiled by GNU C version 4.3.2, GMP version 4.2.2, MPFR version 2.3.2.
GGC heuristics: --param ggc-min-expand=100 --param ggc-min-heapsize=131072
Compiler executable checksum: fbed29247d8ae538bfd0dd565a17225f
COLLECT_GCC_OPTIONS='-O2' '-v' '-mtune=generic'
 as -V -Qy -o /tmp/ccy32lKh.o /tmp/ccxjcnkd.s
GNU assembler version 2.18.93 (i486-linux-gnu) using BFD version (GNU Binutils
for Ubuntu) 2.18.93.20081009
COMPILER_PATH=/usr/lib/gcc/i486-linux-gnu/4.3.2/:/usr/lib/gcc/i486-linux-gnu/4.3.2/:/usr/lib/gcc/i486-linux-gnu/:/usr/lib/gcc/i486-linux-gnu/4.3.2/:/usr/lib/gcc/i486-linux-gnu/:/usr/lib/gcc/i486-linux-gnu/4.3.2/:/usr/lib/gcc/i486-linux-gnu/
LIBRARY_PATH=/usr/lib/gcc/i486-linux-gnu/4.3.2/:/usr/lib/gcc/i486-linux-gnu/4.3.2/:/usr/lib/gcc/i486-linux-gnu/4.3.2/../../../../lib/:/lib/../lib/:/usr/lib/../lib/:/usr/lib/gcc/i486-linux-gnu/4.3.2/../../../:/lib/:/usr/lib/
COLLECT_GCC_OPTIONS='-O2' '-v' '-mtune=generic'
 /usr/lib/gcc/i486-linux-gnu/4.3.2/collect2 --eh-frame-hdr -m elf_i386
--hash-style=both -dynamic-linker /lib/ld-linux.so.2 -z relro
/usr/lib/gcc/i486-linux-gnu/4.3.2/../../../../lib/crt1.o
/usr/lib/gcc/i486-linux-gnu/4.3.2/../../../../lib/crti.o
/usr/lib/gcc/i486-linux-gnu/4.3.2/crtbegin.o
-L/usr/lib/gcc/i486-linux-gnu/4.3.2 -L/usr/lib/gcc/i486-linux-gnu/4.3.2
-L/usr/lib/gcc/i486-linux-gnu/4.3.2/../../../../lib -L/lib/../lib
-L/usr/lib/../lib -L/usr/lib/gcc/i486-linux-gnu/4.3.2/../../.. /tmp/ccy32lKh.o
-lgcc --as-needed -lgcc_s --no-as-needed -lc -lgcc --as-needed -lgcc_s
--no-as-needed /usr/lib/gcc/i486-linux-gnu/4.3.2/crtend.o
/usr/lib/gcc/i486-linux-gnu/4.3.2/../../../../lib/crtn.o


-- 
           Summary: Wrong code when -O3 or -O2 used
           Product: gcc
           Version: 4.3.2
            Status: UNCONFIRMED
          Severity: critical
          Priority: P3
         Component: c
        AssignedTo: unassigned at gcc dot gnu dot org
        ReportedBy: socketpair at gmail dot com
 GCC build triplet: i386
  GCC host triplet: i386
GCC target triplet: i386


http://gcc.gnu.org/bugzilla/show_bug.cgi?id=38616

[Bug c/38616] Wrong code when -O3 or -O2 used

[socketpair at gmail dot com]

------- Comment #1 from socketpair at gmail dot com  2008-12-24 13:27 -------
Created an attachment (id=16979)
 --> (http://gcc.gnu.org/bugzilla/attachment.cgi?id=16979&action=view)
assembler output of wrong generated code

this assembler output generates only 8 characters in output instead of full
constant string. 


-- 


http://gcc.gnu.org/bugzilla/show_bug.cgi?id=38616

[Bug c/38616] Wrong code when -O3 or -O2 used

[socketpair at gmail dot com]

------- Comment #2 from socketpair at gmail dot com  2008-12-24 13:33 -------
(From update of attachment 16979)
        .file   "zzz2.c"
        .text
        .p2align 4,,15
.globl main
        .type   main, @function
main:
        leal    4(%esp), %ecx
        andl    $-16, %esp
        pushl   -4(%ecx)
        pushl   %ebp
        movl    %esp, %ebp
        subl    $1064, %esp
        movl    %gs:20, %eax
        movl    %eax, -12(%ebp)
        xorl    %eax, %eax
        movl    %ecx, -8(%ebp)
        movl    $255, %ecx
        movl    %edi, -4(%ebp)
        leal    -1032(%ebp), %edi
        movl    $875770417, -1036(%ebp)
        movl    $1650536505, -1028(%ebp)
        movl    $1717920867, -1024(%ebp)
        rep stosl
        leal    -1036(%ebp), %eax
        movl    $943142453, -1032(%ebp)
        movl    $1785292903, -1020(%ebp)
        movl    $1852664939, -1016(%ebp)
        movw    $111, -1012(%ebp)
        movl    %eax, (%esp)
        call    puts
        xorl    %eax, %eax
        movl    -12(%ebp), %edx
        xorl    %gs:20, %edx
        jne     .L6
        movl    -8(%ebp), %ecx
        movl    -4(%ebp), %edi
        movl    %ebp, %esp
        popl    %ebp
        leal    -4(%ecx), %esp
        ret
.L6:
        call    __stack_chk_fail
        .size   main, .-main
        .ident  "GCC: (Ubuntu 4.3.2-1ubuntu11) 4.3.2"
        .section        .note.GNU-stack,"",@progbits


-- 


http://gcc.gnu.org/bugzilla/show_bug.cgi?id=38616

[Bug c/38616] Wrong code when -O3 or -O2 used

[socketpair at gmail dot com]

------- Comment #3 from socketpair at gmail dot com  2008-12-24 13:38 -------
(From update of attachment 16979)
(i'm not intentionally send assembler output  for version where buf[1024]
replaced with buf[1023]).


-- 

socketpair at gmail dot com changed:

           What    |Removed                     |Added
----------------------------------------------------------------------------
  Attachment #16979|assembler output of wrong   |assembler output of wrong
        description|generated code              |generated code


http://gcc.gnu.org/bugzilla/show_bug.cgi?id=38616

[Bug middle-end/38616] [4.3 only] Wrong code when -O3 or -O2 -fstack-protector used

[pinskia at gcc dot gnu dot org]

------- Comment #4 from pinskia at gcc dot gnu dot org  2008-12-24 13:57 -------
-fno-fstack-protector is a work around.  Ubuntu must enable stack protector by
default.

Note it works on the trunk but fails on an older 4.3.3:
gcc version 4.3.3 20081218 (prerelease) [gcc-4_3-branch revision 142804] (GCC) 


I don't have 4.2 to test.


-- 

pinskia at gcc dot gnu dot org changed:

           What    |Removed                     |Added
----------------------------------------------------------------------------
           Severity|critical                    |normal
          Component|c                           |middle-end
      Known to fail|                            |4.3.3
      Known to work|                            |4.4.0
            Summary|Wrong code when -O3 or -O2  |[4.3 only] Wrong code when -
                   |used                        |O3 or -O2 -fstack-protector
                   |                            |used
   Target Milestone|---                         |4.3.3


http://gcc.gnu.org/bugzilla/show_bug.cgi?id=38616

[Bug middle-end/38616] [4.3 only] Wrong code when -O3 or -O2 -fstack-protector used

[socketpair at gmail dot com]

------- Comment #5 from socketpair at gmail dot com  2008-12-24 15:21 -------
-fno-stack-protector really helps.

i don't understand why "rep stosl" appear in the middle of string
initialization..
gdb said that "rep stosl" is a cause of zero byte after first 8 symbols.

also, if this bug does not appear in 4.4.0, i want to see decription of
corrected bug (maybe dup of mine)


-- 


http://gcc.gnu.org/bugzilla/show_bug.cgi?id=38616

[Bug middle-end/38616] [4.3 only] Wrong code when -O3 or -O2 -fstack-protector used

[socketpair at gmail dot com]

------- Comment #6 from socketpair at gmail dot com  2008-12-24 15:28 -------
> -fno-fstack-protector is a work around.  Ubuntu must enable stack protector by
default.

I don't understand. Ubuntu enabled stack protector by default now. Is this
error? 
Should i report bug to Ubuntu? 

It stack protector experimental feature?


-- 


http://gcc.gnu.org/bugzilla/show_bug.cgi?id=38616

[Bug middle-end/38616] [4.3 Regression] Wrong code when -O3 or -O2 -fstack-protector used

[rguenth at gcc dot gnu dot org]

------- Comment #7 from rguenth at gcc dot gnu dot org  2008-12-29 20:38 -------
Confirmed.  Probably fixed on the trunk by

2008-05-04  Uros Bizjak  <ubizjak@gmail.com>

        * config/i386/i386.md (*strmovsi_1): Simplify asm alternatives.
        (*strmovsi_rex_1): Ditto.
        (*strsetsi_1): Ditto.
        (*strsetsi_rex_1): Ditto.

        (add<mode>cc): Macroize expander from addqicc, addhicc, addsicc and
        adddicc expanders using SWI mode iterator.

?


-- 

rguenth at gcc dot gnu dot org changed:

           What    |Removed                     |Added
----------------------------------------------------------------------------
                 CC|                            |rguenth at gcc dot gnu dot
                   |                            |org, ubizjak at gmail dot
                   |                            |com
             Status|UNCONFIRMED                 |NEW
     Ever Confirmed|0                           |1
  GCC build triplet|i386                        |
   GCC host triplet|i386                        |
 GCC target triplet|i386                        |i?86
      Known to fail|4.3.3                       |4.3.0 4.3.3
      Known to work|4.4.0                       |4.2.4 4.4.0
           Priority|P3                          |P2
   Last reconfirmed|0000-00-00 00:00:00         |2008-12-29 20:38:21
               date|                            |
            Summary|[4.3 only] Wrong code when -|[4.3 Regression] Wrong code
                   |O3 or -O2 -fstack-protector |when -O3 or -O2 -fstack-
                   |used                        |protector used


http://gcc.gnu.org/bugzilla/show_bug.cgi?id=38616

[Bug middle-end/38616] [4.3 Regression] Wrong code when -O3 or -O2 -fstack-protector used

[doko at gcc dot gnu dot org]

------- Comment #8 from doko at gcc dot gnu dot org  2009-01-11 17:29 -------
Subject: Bug 38616

Author: doko
Date: Sun Jan 11 17:29:23 2009
New Revision: 143276

URL: http://gcc.gnu.org/viewcvs?root=gcc&view=rev&rev=143276
Log:
gcc/

2009-01-11  Matthias Klose  <doko@ubuntu.com>

        PR middle-end/38616, backport from mainline:
        2008-05-04  Uros Bizjak  <ubizjak@gmail.com>

        * config/i386/i386.md (*strmovsi_1): Simplify asm alternatives.
        (*strmovsi_rex_1): Ditto.
        (*strsetsi_1): Ditto.
        (*strsetsi_rex_1): Ditto.

        (add<mode>cc): Macroize expander from addqicc, addhicc, addsicc and
        adddicc expanders using SWI mode iterator.

gcc/testsuite/

2009-01-11  Matthias Klose  <doko@ubuntu.com>

        PR middle-end/38616
        * gcc.dg/pr38616.c: New test.

Added:
    branches/gcc-4_3-branch/gcc/testsuite/gcc.dg/pr38616.c
Modified:
    branches/gcc-4_3-branch/gcc/ChangeLog
    branches/gcc-4_3-branch/gcc/config/i386/i386.md
    branches/gcc-4_3-branch/gcc/testsuite/ChangeLog


-- 


http://gcc.gnu.org/bugzilla/show_bug.cgi?id=38616

[Bug middle-end/38616] [4.3 Regression] Wrong code when -O3 or -O2 -fstack-protector used

[doko at gcc dot gnu dot org]

------- Comment #9 from doko at gcc dot gnu dot org  2009-01-11 17:38 -------
Subject: Bug 38616

Author: doko
Date: Sun Jan 11 17:38:22 2009
New Revision: 143277

URL: http://gcc.gnu.org/viewcvs?root=gcc&view=rev&rev=143277
Log:
2009-01-11  Matthias Klose  <doko@ubuntu.com>

        PR middle-end/38616
        * gcc.dg/pr38616.c: New test.

Added:
    trunk/gcc/testsuite/gcc.dg/pr38616.c
Modified:
    trunk/gcc/testsuite/ChangeLog


-- 


http://gcc.gnu.org/bugzilla/show_bug.cgi?id=38616

[Bug middle-end/38616] [4.3 Regression] Wrong code when -O3 or -O2 -fstack-protector used

[danglin at gcc dot gnu dot org]

------- Comment #10 from danglin at gcc dot gnu dot org  2009-01-14 19:18 -------
Test fails on hppa64-hp-hpux11.11:

Executing on host: /mnt/gnu/gcc/objdir/gcc/xgcc -B/mnt/gnu/gcc/objdir/gcc/
/mnt/
gnu/gcc/gcc/gcc/testsuite/gcc.dg/pr38616.c   -O2 -fstack-protector
-fno-show-col
umn  -lm   -o ./pr38616.exe    (timeout = 300)
/mnt/gnu/gcc/gcc/gcc/testsuite/gcc.dg/pr38616.c:1: warning: -fstack-protector
no
t supported for this target
ld: Can't find library for -lssp_nonshared
Fatal error.
collect2: ld returned 1 exit status
compiler exited with status 1
output is:
/mnt/gnu/gcc/gcc/gcc/testsuite/gcc.dg/pr38616.c:1: warning: -fstack-protector
no
t supported for this target
ld: Can't find library for -lssp_nonshared
Fatal error.
collect2: ld returned 1 exit status


-- 

danglin at gcc dot gnu dot org changed:

           What    |Removed                     |Added
----------------------------------------------------------------------------
                 CC|                            |danglin at gcc dot gnu dot
                   |                            |org


http://gcc.gnu.org/bugzilla/show_bug.cgi?id=38616

[Bug middle-end/38616] [4.3 Regression] Wrong code when -O3 or -O2 -fstack-protector used

[pinskia at gcc dot gnu dot org]

------- Comment #11 from pinskia at gcc dot gnu dot org  2009-01-14 19:24 -------
>/mnt/gnu/gcc/gcc/gcc/testsuite/gcc.dg/pr38616.c:1: warning: -fstack-protector

That has already been fixed:
http://gcc.gnu.org/ml/gcc-cvs/2009-01/msg00372.html


Fixed so closing.


-- 

pinskia at gcc dot gnu dot org changed:

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


http://gcc.gnu.org/bugzilla/show_bug.cgi?id=38616

[Bug middle-end/38616] [4.3 Regression] Wrong code when -O3 or -O2 -fstack-protector used

[hjl dot tools at gmail dot com]

------- Comment #12 from hjl dot tools at gmail dot com  2009-01-18 17:07 -------
It isn't fixed in 4.3.3. See PR 38902. I will search which
revision fixes it on trunk.


-- 

hjl dot tools at gmail dot com changed:

           What    |Removed                     |Added
----------------------------------------------------------------------------
  BugsThisDependsOn|                            |38902
             Status|RESOLVED                    |REOPENED
         Resolution|FIXED                       |


http://gcc.gnu.org/bugzilla/show_bug.cgi?id=38616

[Bug middle-end/38616] [4.3 Regression] Wrong code when -O3 or -O2 -fstack-protector used

[hjl dot tools at gmail dot com]

------- Comment #13 from hjl dot tools at gmail dot com  2009-01-18 22:06 -------
PR 38902 has a much better testcase.

*** This bug has been marked as a duplicate of 38902 ***


-- 

hjl dot tools at gmail dot com changed:

           What    |Removed                     |Added
----------------------------------------------------------------------------
  BugsThisDependsOn|38902                       |
             Status|REOPENED                    |RESOLVED
         Resolution|                            |DUPLICATE


http://gcc.gnu.org/bugzilla/show_bug.cgi?id=38616