[Bug c/30247] New: [4.2/4.3] Gcc miscompiles MPlayer when any optimization is used

[Bug c/30247] New: [4.2/4.3] Gcc miscompiles MPlayer when any optimization is used

[ismail at pardus dot org dot tr]

gcc 4.2 branch and gcc 4.3 SVN snapshot seems to miscompile MPlayer's mp_msg.c
resulting in a crash. gcc 3.4.6 is ok. During compilation no warning is issued.

Gcc tested is :
Using built-in specs.
Target: i686-pc-linux-gnu
Configured with: ../gcc/configure --prefix=/home/cartman/gcc_4.2
--enable-clocale=gnu --enable-shared --enable-threads=posix
--enable-__cxa_atexit --enable-languages=c,c++ --disable-nls
Thread model: posix
gcc version 4.2.0 20061217 (prerelease)


I will attach two files:

mp_msg_compiled_with_O1_crashes.i produced with :

cc -O1 -Wdeclaration-after-statement -march=pentium-m -mtune=pentium-m -pipe
-ffast-math -fomit-frame-pointer -D_REENTRANT -D_LARGEFILE_SOURCE
-D_FILE_OFFSET_BITS=64 -D_LARGEFILE64_SOURCE -I/usr/include -I/usr/include/ 
-I/usr/include/SDL  -D_REENTRANT -I/usr/include -I/usr/include/dvdnav 
-I/usr/include/freetype2 -I. -I./libavutil -I./libavcodec  -c -save-temps
mp_msg.c

mp_msg_compiled_with_O0_works.i produced with:

cc -O0 -Wdeclaration-after-statement -march=pentium-m -mtune=pentium-m -pipe
-ffast-math -fomit-frame-pointer -D_REENTRANT -D_LARGEFILE_SOURCE
-D_FILE_OFFSET_BITS=64 -D_LARGEFILE64_SOURCE -I/usr/include -I/usr/include/ 
-I/usr/include/SDL  -D_REENTRANT -I/usr/include -I/usr/include/dvdnav 
-I/usr/include/freetype2 -I. -I./libavutil -I./libavcodec  -c -save-temps
mp_msg.c


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           Summary: [4.2/4.3] Gcc miscompiles MPlayer when any optimization
                    is used
           Product: gcc
           Version: 4.2.0
            Status: UNCONFIRMED
          Severity: normal
          Priority: P3
         Component: c
        AssignedTo: unassigned at gcc dot gnu dot org
        ReportedBy: ismail at pardus dot org dot tr


http://gcc.gnu.org/bugzilla/show_bug.cgi?id=30247

[Bug c/30247] [4.2/4.3] Gcc miscompiles MPlayer when any optimization is used

[ismail at pardus dot org dot tr]

------- Comment #1 from ismail at pardus dot org dot tr  2006-12-18 10:10 -------
Created an attachment (id=12823)
 --> (http://gcc.gnu.org/bugzilla/attachment.cgi?id=12823&action=view)
mp_msg.c compiled with -O0


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http://gcc.gnu.org/bugzilla/show_bug.cgi?id=30247

[Bug c/30247] [4.2/4.3] Gcc miscompiles MPlayer when any optimization is used

[ismail at pardus dot org dot tr]

------- Comment #2 from ismail at pardus dot org dot tr  2006-12-18 10:11 -------
Created an attachment (id=12824)
 --> (http://gcc.gnu.org/bugzilla/attachment.cgi?id=12824&action=view)
mp_msg.c compiled with -O1


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http://gcc.gnu.org/bugzilla/show_bug.cgi?id=30247

[Bug c/30247] [4.2/4.3] Gcc miscompiles MPlayer when any optimization is used

[ismail at pardus dot org dot tr]

------- Comment #3 from ismail at pardus dot org dot tr  2006-12-18 10:15 -------
Valgrinding the crashing mplayer shows:

==5836== Invalid read of size 1
==5836==    at 0x401E776: strlen 
(in /usr/lib/valgrind/x86-linux/vgpreload_memcheck.so)
==5836==    by 0x4B4049E: fprintf (in /lib/libc-2.3.6.so)
==5836==    by 0x81098CF: open (vf_ass.c:395)
==5836==    by 0x80DC4F6: vf_open_plugin (vf.c:466)
==5836==    by 0x80831F6: reinit_video_chain (mplayer.c:3321)
==5836==    by 0x8086699: main (mplayer.c:4517)
==5836==  Address 0x5248003E is not stack'd, malloc'd or (recently) free'd      
which shows line 182 in mp_msg.c which is something like:

  fprintf(stream, "\033[%d;3%dm%9s\033[0;37m: ",c2>>3,c2&7, 
mod_text[mod]);

If I replace mod_text[mod] with "foo" it doesn't crash anymore.


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http://gcc.gnu.org/bugzilla/show_bug.cgi?id=30247

[Bug middle-end/30247] [4.2/4.3] Gcc miscompiles MPlayer when any optimization is used

[pinskia at gcc dot gnu dot org]

------- Comment #4 from pinskia at gcc dot gnu dot org  2006-12-18 10:26 -------
There is no obvious what is wrong from the tree dumps.


-- 

pinskia at gcc dot gnu dot org changed:

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


http://gcc.gnu.org/bugzilla/show_bug.cgi?id=30247

[Bug middle-end/30247] [4.2/4.3] Gcc miscompiles MPlayer when any optimization is used

[ismail at pardus dot org dot tr]

------- Comment #5 from ismail at pardus dot org dot tr  2006-12-18 10:39 -------
I tried to follow http://gcc.gnu.org/bugs.html#need . Anything else I should
provide?


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http://gcc.gnu.org/bugzilla/show_bug.cgi?id=30247

[Bug middle-end/30247] [4.2/4.3] Gcc miscompiles MPlayer when any optimization is used

[ismail at pardus dot org dot tr]

------- Comment #6 from ismail at pardus dot org dot tr  2006-12-19 09:31 -------
Another MPlayer bug exposed by gcc, sorry guys!


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ismail at pardus dot org dot tr changed:

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


http://gcc.gnu.org/bugzilla/show_bug.cgi?id=30247