[Bug c++/13685] New: Building KDE3.2 clock applet with -march=pentium3 -O1 gives SIGSEGV

[Bug c++/13685] New: Building KDE3.2 clock applet with -march=pentium3 -O1 gives SIGSEGV

[roger dot larsson at norran dot net]

See (lots of confusion...) 
 http://bugs.kde.org/show_bug.cgi?id=70655 
 
I will attach source and assembly.

-- 
           Summary: Building KDE3.2 clock applet with -march=pentium3 -O1
                    gives SIGSEGV
           Product: gcc
           Version: 3.3.1
            Status: UNCONFIRMED
          Severity: normal
          Priority: P2
         Component: c++
        AssignedTo: unassigned at gcc dot gnu dot org
        ReportedBy: roger dot larsson at norran dot net
                CC: gcc-bugs at gcc dot gnu dot org


http://gcc.gnu.org/bugzilla/show_bug.cgi?id=13685

[Bug c++/13685] Building KDE3.2 clock applet with -march=pentium3 -O1 gives SIGSEGV

[roger dot larsson at norran dot net]

------- Additional Comments From roger dot larsson at norran dot net  2004-01-14 18:33 -------
Created an attachment (id=5487)
 --> (http://gcc.gnu.org/bugzilla/attachment.cgi?id=5487&action=view)
c++ source from kde/kdebase/kicker/applets/clock/

crash at line 536

-- 


http://gcc.gnu.org/bugzilla/show_bug.cgi?id=13685

[Bug target/13685] Building KDE3.2 clock applet with -march=pentium3 -O1 gives SIGSEGV

[pinskia at gcc dot gnu dot org]

------- Additional Comments From pinskia at gcc dot gnu dot org  2004-01-14 18:34 -------
I think the problem is that the stack is unaligned causing the problem, I know there is another bug 
for that, if that is the bug, can you just mark it as a dup, I think it is suspended.

-- 
           What    |Removed                     |Added
----------------------------------------------------------------------------
          Component|c++                         |target


http://gcc.gnu.org/bugzilla/show_bug.cgi?id=13685

[Bug target/13685] Building KDE3.2 clock applet with -march=pentium3 -O1 gives SIGSEGV

[roger dot larsson at norran dot net]

------- Additional Comments From roger dot larsson at norran dot net  2004-01-14 19:51 -------
Created an attachment (id=5489)
 --> (http://gcc.gnu.org/bugzilla/attachment.cgi?id=5489&action=view)
Assembly output

Crashes at this line when compiled with -march=pentium3 [-mcpu=pentium3] -O1
(There is only one movaps...)

	0x41a8867b AnalogClock::paintEvent   movaps %xmm0,0xfffffc78(%ebp)

where

ebp	       0xbfffea60	0xbfffea60

This will generate a non 16 byte aligned access!!!
=> Crash

-- 


http://gcc.gnu.org/bugzilla/show_bug.cgi?id=13685

[Bug target/13685] Building KDE3.2 clock applet with -march=pentium3 -O1 gives SIGSEGV

[roger dot larsson at norran dot net]

------- Additional Comments From roger dot larsson at norran dot net  2004-01-14 23:50 -------
Code is not from a lib, it is generated by gcc. 
=> I do not think this is a DUP of bug 10395 
 
I did a little script to search for the problems. 
# /bin/bash 
# Filename: objdump_find_problematic 
 
grep_sse () 
{ 
	grep $1 "\(\(mov\(ap\|up\|ntp\)\|shufp\|unpck\(hp\|lp\)\|\(add\|\mul\|
div\|and\|andn\|or\|xor\|max\|min\|cmp\.\.\|sqrt\|rsqrt\|rcp\)p\)s\|
\(cvt\(ps2pi\|ss2pi\)\)\)" 
} 
 
if objdump -d $1 | grep_sse -q ; then 
   echo $1 
   objdump -d $1 | grep_sse 
fi 
 
and run my complete installation of kdecvs (-Os -march=pentium3) through it. 
 
# find /opt/kdecvs/ -type f -perm +111 | xargs -n 1 
bin/objdump_find_problematic | tee problematic.sse 
 
Among those found where 
	kfiresaver3d starting it will crash at a unaligned movaps 
	 (actual code from glibc-2.3) 
 
Complete list, some are OK with aligned offset: 
 
# more problematic.sse | grep "0x\|opt" 
/opt/kdecvs/bin/kdm_greet 
 805e5ac:       0f 29 85 98 fc ff ff    movaps %xmm0,0xfffffc98(%ebp) 
/opt/kdecvs/bin/keuphoria.kss 
 804fe6e:       0f 29 45 e0             movaps %xmm0,0xffffffe0(%ebp) 
 80500fd:       0f 29 45 d0             movaps %xmm0,0xffffffd0(%ebp) 
/opt/kdecvs/bin/kfiresaver3d 
 80502ac:       0f 29 85 7c ff ff ff    movaps %xmm0,0xffffff7c(%ebp) 
 8050529:       0f 29 85 64 ff ff ff    movaps %xmm0,0xffffff64(%ebp) 
/opt/kdecvs/lib/libartsflow.so.1.0.0 
/opt/kdecvs/lib/kde3/kdeprint_cups.so 
   4042d:       0f 29 45 8c             movaps %xmm0,0xffffff8c(%ebp) 
/opt/kdecvs/lib/kde3/kcm_clock.so 
    e294:       0f 29 85 20 fe ff ff    movaps %xmm0,0xfffffe20(%ebp) 
/opt/kdecvs/lib/kde3/libkiviopart.so 
   f8a94:       0f 29 45 a8             movaps %xmm0,0xffffffa8(%ebp) 
   f8d47:       0f 29 45 80             movaps %xmm0,0xffffff80(%ebp) 
   f90ad:       0f 29 85 5c ff ff ff    movaps %xmm0,0xffffff5c(%ebp) 
   fa0ac:       0f 29 45 a8             movaps %xmm0,0xffffffa8(%ebp) 
   fa305:       0f 29 45 a4             movaps %xmm0,0xffffffa4(%ebp) 
/opt/kdecvs/lib/kde3/libkpovmodelerpart.so.0.0.0 
/opt/kdecvs/lib/libkdefx.so.4.2.0 
/opt/kdecvs/lib/libnoatunarts.so 
   576d8:       0f 10 51 10             movups 0x10(%ecx),%xmm2 
   576dc:       0f c6 d2 00             shufps $0x0,%xmm2,%xmm2 
   576e0:       0f 10 61 14             movups 0x14(%ecx),%xmm4 
   576e4:       0f 10 69 24             movups 0x24(%ecx),%xmm5 
   57720:       0f c6 c8 b1             shufps $0xb1,%xmm0,%xmm1 
   57737:       0f c6 c5 24             shufps $0x24,%xmm5,%xmm0 
   5773b:       0f c6 e8 81             shufps $0x81,%xmm0,%xmm5 
   57743:       0f c6 db 39             shufps $0x39,%xmm3,%xmm3 
   57747:       0f c6 f6 39             shufps $0x39,%xmm6,%xmm6 
   57752:       0f 11 69 24             movups %xmm5,0x24(%ecx) 
   60ea4:       0f c6 c9 00             shufps $0x0,%xmm1,%xmm1 
   60ee6:       0f c6 c2 00             shufps $0x0,%xmm2,%xmm0 
   60ef5:       0f c6 c0 02             shufps $0x2,%xmm0,%xmm0 
 
This is a BIG problem! (kivio, and kfiresaver3d have been verified to crash) 

-- 


http://gcc.gnu.org/bugzilla/show_bug.cgi?id=13685

[Bug target/13685] Building KDE3.2 clock applet with -march=pentium3 -O1 gives SIGSEGV

[thiagom at mail dot com]

-- 
           What    |Removed                     |Added
----------------------------------------------------------------------------
                 CC|                            |thiagom at mail dot com


http://gcc.gnu.org/bugzilla/show_bug.cgi?id=13685

[Bug target/13685] Building KDE3.2 clock applet with -march=pentium3 -O1 gives SIGSEGV

[dhazeghi at yahoo dot com]

------- Additional Comments From dhazeghi at yahoo dot com  2004-01-18 18:07 -------
Your report seems to indicate that the problematic asm is produced all over the
place. Can you either provide preprocessed source, or (better, and if the
problem is widespread, should not be too difficult) a small, self-contained
testcase? Thanks.

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


http://gcc.gnu.org/bugzilla/show_bug.cgi?id=13685

[Bug target/13685] Building KDE3.2 clock applet with -march=pentium3 -O1 gives SIGSEGV

[roger dot larsson at norran dot net]

------- Additional Comments From roger dot larsson at norran dot net  2004-01-19 06:38 -------
I am currently trying to create a testcase - the instructions gets generated 
but I do not get it unaligned - to crash... 
 
-O1 -march=pentium3 
 
Gives the instructions (movaps) 
 
-O1 -march=pentium3 -mno-sse 
 
Is needed to avoid them. 
 

-- 


http://gcc.gnu.org/bugzilla/show_bug.cgi?id=13685

[Bug target/13685] Building KDE3.2 clock applet with -march=pentium3 -O1 gives SIGSEGV

[roger dot larsson at norran dot net]

------- Additional Comments From roger dot larsson at norran dot net  2004-01-19 08:11 -------
This is the shortest code yet (matrix.cpp) I found that generates the 
offending instruction (movaps) - but I have not yet succeeded in getting 
the stack unaligned... [Do you need that too?] 
 
class RTime 
{ 
public: 
    int minute() {} 
}; 
 
void rotate(float x) 
{ 
} 
 
int main() 
{ 
    RTime _time; 
 
    // hour 
    float h_angle = _time.minute(); 
    rotate(-h_angle); 
 
    // minute 
    float m_angle = _time.minute(); 
    rotate(-m_angle); 
} 
 
I am pretty sure that Qt should be simple to  
Compile with: 
gcc -I/usr/src/kde/qt-copy/mkspecs/linux-g++ -I../../include -o matrix.o 
-march=pentium3 -O1 matrix.cpp 

-- 


http://gcc.gnu.org/bugzilla/show_bug.cgi?id=13685

Re: [Bug target/13685] Building KDE3.2 clock applet with -march=pentium3 -O1 gives SIGSEGV

[Jan Hubicka]

> 
> ------- Additional Comments From roger dot larsson at norran dot net  2004-01-19 08:11 -------
> This is the shortest code yet (matrix.cpp) I found that generates the 
> offending instruction (movaps) - but I have not yet succeeded in getting 
> the stack unaligned... [Do you need that too?] 

Roger,
I am not able to reproduce it from your testcase, but sending the
assembly file produces with g++ -O1 -march=pentium3 -dp -S will probably
give me enough information to fix it.

Thanks!
Honza
>  
> class RTime 
> { 
> public: 
>     int minute() {} 
> }; 
>  
> void rotate(float x) 
> { 
> } 
>  
> int main() 
> { 
>     RTime _time; 
>  
>     // hour 
>     float h_angle = _time.minute(); 
>     rotate(-h_angle); 
>  
>     // minute 
>     float m_angle = _time.minute(); 
>     rotate(-m_angle); 
> } 
>  
> I am pretty sure that Qt should be simple to  
> Compile with: 
> gcc -I/usr/src/kde/qt-copy/mkspecs/linux-g++ -I../../include -o matrix.o 
> -march=pentium3 -O1 matrix.cpp 
> 
> -- 
> 
> 
> http://gcc.gnu.org/bugzilla/show_bug.cgi?id=13685

[Bug target/13685] Building KDE3.2 clock applet with -march=pentium3 -O1 gives SIGSEGV

[hubicka at ucw dot cz]

------- Additional Comments From hubicka at ucw dot cz  2004-01-19 10:42 -------
Subject: Re:  Building KDE3.2 clock applet with -march=pentium3 -O1 gives SIGSEGV

> 
> ------- Additional Comments From roger dot larsson at norran dot net  2004-01-19 08:11 -------
> This is the shortest code yet (matrix.cpp) I found that generates the 
> offending instruction (movaps) - but I have not yet succeeded in getting 
> the stack unaligned... [Do you need that too?] 

Roger,
I am not able to reproduce it from your testcase, but sending the
assembly file produces with g++ -O1 -march=pentium3 -dp -S will probably
give me enough information to fix it.

Thanks!
Honza
>  
> class RTime 
> { 
> public: 
>     int minute() {} 
> }; 
>  
> void rotate(float x) 
> { 
> } 
>  
> int main() 
> { 
>     RTime _time; 
>  
>     // hour 
>     float h_angle = _time.minute(); 
>     rotate(-h_angle); 
>  
>     // minute 
>     float m_angle = _time.minute(); 
>     rotate(-m_angle); 
> } 
>  
> I am pretty sure that Qt should be simple to  
> Compile with: 
> gcc -I/usr/src/kde/qt-copy/mkspecs/linux-g++ -I../../include -o matrix.o 
> -march=pentium3 -O1 matrix.cpp 
> 
> -- 
> 
> 
> http://gcc.gnu.org/bugzilla/show_bug.cgi?id=13685


-- 


http://gcc.gnu.org/bugzilla/show_bug.cgi?id=13685

[Bug target/13685] Building KDE3.2 clock applet with -march=pentium3 -O1 gives SIGSEGV

[roger dot larsson at norran dot net]

------- Additional Comments From roger dot larsson at norran dot net  2004-01-19 12:48 -------
I guess no more WAITING is needed -> NEW 

-- 
           What    |Removed                     |Added
----------------------------------------------------------------------------
             Status|WAITING                     |NEW
     Ever Confirmed|                            |1


http://gcc.gnu.org/bugzilla/show_bug.cgi?id=13685

[Bug target/13685] Building simple test application with -march=pentium3 -Os gives SIGSEGV (unaligned sse instruction)

[roger dot larsson at norran dot net]

------- Additional Comments From roger dot larsson at norran dot net  2005-01-07 09:49 -------
Got a query about this bug...   
   
It is still valid for gcc 3.3.4   
My computer has been upgraded to a athlon-xp, so I tested both   
   
g++ -Os -march=pentium3 matrix.cpp -o matrix   
 and   
g++ -Os -march=athlon-xp matrix.cpp -o matrix   
   
they both gives Segmentation fault when running   
./matrix   
   
Other optimization levels works.  
   
Updated summary etc.  
   

-- 
           What    |Removed                     |Added
----------------------------------------------------------------------------
           Keywords|                            |wrong-code
           Priority|P2                          |P1
            Summary|Building KDE3.2 clock applet|Building simple test
                   |with -march=pentium3 -O1    |application with -
                   |gives SIGSEGV               |march=pentium3 -Os gives
                   |                            |SIGSEGV (unaligned sse
                   |                            |instruction)
            Version|3.3.1                       |3.3.4


http://gcc.gnu.org/bugzilla/show_bug.cgi?id=13685

[Bug target/13685] Building simple test application with -march=pentium3 -Os gives SIGSEGV (unaligned sse instruction)

[belyshev at depni dot sinp dot msu dot ru]

------- Comment #14 from belyshev at depni dot sinp dot msu dot ru  2006-02-21 12:38 -------
*** Bug 15617 has been marked as a duplicate of this bug. ***


-- 

belyshev at depni dot sinp dot msu dot ru changed:

           What    |Removed                     |Added
----------------------------------------------------------------------------
                 CC|                            |kpfleming at
                   |                            |backtobasicsmgmt dot com


http://gcc.gnu.org/bugzilla/show_bug.cgi?id=13685

[Bug target/13685] Building simple test application with -march=pentium3 -Os gives SIGSEGV (unaligned sse instruction)

[belyshev at depni dot sinp dot msu dot ru]

------- Comment #15 from belyshev at depni dot sinp dot msu dot ru  2006-02-21 12:45 -------
Another testcase, use "-Os -msse", fails with all versions since 3.2:


typedef float __m128 __attribute__ ((vector_size (16)));
typedef int __m64 __attribute__ ((vector_size (8)));

int puts (const char *s);
void foo (__m128 *, __m64 *, int);

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

void foo (__m128 *dst, __m64 *src, int n)
{
  __m128 xmm0 = { 0 };
  while (n > 64)
    {
      puts ("");
      xmm0 = __builtin_ia32_cvtpi2ps (xmm0, *src);
      *dst = xmm0;
      n --;
    }
}


-- 

belyshev at depni dot sinp dot msu dot ru changed:

           What    |Removed                     |Added
----------------------------------------------------------------------------
      Known to fail|                            |3.2.3 3.3.6 3.4.6 4.0.3
                   |                            |4.1.0 4.2.0
   Last reconfirmed|0000-00-00 00:00:00         |2006-02-21 12:45:28
               date|                            |


http://gcc.gnu.org/bugzilla/show_bug.cgi?id=13685

[Bug target/13685] Building simple test application with -march=pentium3 -Os gives SIGSEGV (unaligned sse instruction)

[belyshev at depni dot sinp dot msu dot ru]

------- Comment #16 from belyshev at depni dot sinp dot msu dot ru  2006-02-21 12:51 -------
raising severity because this bug makes "-Os" almost useless on modern x86.


-- 

belyshev at depni dot sinp dot msu dot ru changed:

           What    |Removed                     |Added
----------------------------------------------------------------------------
                 CC|                            |belyshev at depni dot sinp
                   |                            |dot msu dot ru
           Severity|normal                      |major


http://gcc.gnu.org/bugzilla/show_bug.cgi?id=13685

[Bug target/13685] Building simple test application with -march=pentium3 -Os gives SIGSEGV (unaligned sse instruction)

[uros at kss-loka dot si]

------- Comment #17 from uros at kss-loka dot si  2006-02-22 10:15 -------
Works OK with gcc-4.2 and -Os -msse -fomit-frame-pointer.


-- 

uros at kss-loka dot si changed:

           What    |Removed                     |Added
----------------------------------------------------------------------------
                 CC|                            |uros at kss-loka dot si


http://gcc.gnu.org/bugzilla/show_bug.cgi?id=13685

[Bug target/13685] Building simple test application with -march=pentium3 -Os gives SIGSEGV (unaligned sse instruction)

[roger dot larsson at norran dot net]

------- Comment #18 from roger dot larsson at norran dot net  2006-02-22 11:31 -------
(In reply to comment #16)
> raising severity because this bug makes "-Os" almost useless on modern x86.
> 
With "gcc version 4.0.2 20050901 (prerelease) (SUSE Linux)"
my testcase works but not Serge Belyshevs 


-- 


http://gcc.gnu.org/bugzilla/show_bug.cgi?id=13685

[Bug target/13685] Building simple test application with -march=pentium3 -Os gives SIGSEGV (unaligned sse instruction)

[jason at gcc dot gnu dot org]

-- 

jason at gcc dot gnu dot org changed:

           What    |Removed                     |Added
----------------------------------------------------------------------------
         AssignedTo|unassigned at gcc dot gnu   |jason at gcc dot gnu dot org
                   |dot org                     |
             Status|NEW                         |ASSIGNED
   Last reconfirmed|2006-02-21 12:45:28         |2006-09-07 19:45:38
               date|                            |


http://gcc.gnu.org/bugzilla/show_bug.cgi?id=13685

[Bug target/13685] Building simple test application with -march=pentium3 -Os gives SIGSEGV (unaligned sse instruction)

[jason at gcc dot gnu dot org]

------- Comment #19 from jason at gcc dot gnu dot org  2006-09-07 20:24 -------
You can work around this bug with -mpreferred-stack-boundary=4


-- 


http://gcc.gnu.org/bugzilla/show_bug.cgi?id=13685

[Bug target/13685] Building simple test application with -march=pentium3 -Os gives SIGSEGV (unaligned sse instruction)

[jason at gcc dot gnu dot org]

------- Comment #20 from jason at gcc dot gnu dot org  2006-09-08 00:28 -------
Subject: Bug 13685

Author: jason
Date: Fri Sep  8 00:28:30 2006
New Revision: 116775

URL: http://gcc.gnu.org/viewcvs?root=gcc&view=rev&rev=116775
Log:
        PR target/13685
        * config/i386/i386.c (override_options): Use 128-bit
        stack boundary if -msse.

Added:
    trunk/gcc/testsuite/gcc.target/i386/sse-20.c
Modified:
    trunk/gcc/ChangeLog
    trunk/gcc/config/i386/i386.c


-- 


http://gcc.gnu.org/bugzilla/show_bug.cgi?id=13685

[Bug target/13685] Building simple test application with -march=pentium3 -Os gives SIGSEGV (unaligned sse instruction)

[hjl at lucon dot org]

------- Comment #21 from hjl at lucon dot org  2006-09-08 00:45 -------
*** Bug 27537 has been marked as a duplicate of this bug. ***


-- 

hjl at lucon dot org changed:

           What    |Removed                     |Added
----------------------------------------------------------------------------
                 CC|                            |agner at agner dot org


http://gcc.gnu.org/bugzilla/show_bug.cgi?id=13685

[Bug target/13685] Building simple test application with -march=pentium3 -Os gives SIGSEGV (unaligned sse instruction)

[hjl at gcc dot gnu dot org]

------- Comment #22 from hjl at gcc dot gnu dot org  2006-09-11 21:34 -------
Subject: Bug 13685

Author: hjl
Date: Mon Sep 11 21:34:06 2006
New Revision: 116860

URL: http://gcc.gnu.org/viewcvs?root=gcc&view=rev&rev=116860
Log:
gcc/

2006-09-11  H.J. Lu  <hongjiu.lu@intel.com>

        PR target/13685
        PR target/27537
        PR target/28621
        * config/i386/i386.c (override_options): Always default to 16
        byte stack boundary.

gcc/testsuite/

2006-09-11  H.J. Lu  <hongjiu.lu@intel.com>

        PR target/13685
        * gcc.target/i386/pr13685.c: New test.

Added:
    trunk/gcc/testsuite/gcc.target/i386/pr13685.c
Modified:
    trunk/gcc/ChangeLog
    trunk/gcc/config/i386/i386.c
    trunk/gcc/testsuite/ChangeLog


-- 


http://gcc.gnu.org/bugzilla/show_bug.cgi?id=13685

[Bug target/13685] Building simple test application with -march=pentium3 -Os gives SIGSEGV (unaligned sse instruction)

[hjl at gcc dot gnu dot org]

------- Comment #23 from hjl at gcc dot gnu dot org  2006-09-12 02:54 -------
Subject: Bug 13685

Author: hjl
Date: Tue Sep 12 02:54:42 2006
New Revision: 116870

URL: http://gcc.gnu.org/viewcvs?root=gcc&view=rev&rev=116870
Log:
gcc/

2006-09-11  H.J. Lu  <hongjiu.lu@intel.com>

        PR target/13685
        PR target/27537
        PR target/28621
        * config/i386/i386.c (override_options): Always default to 16
        byte stack boundary.

gcc/testsuite/

2006-09-11  H.J. Lu  <hongjiu.lu@intel.com>

        PR target/13685
        * gcc.target/i386/pr13685.c: New test.

Added:
    branches/gcc-4_1-branch/gcc/testsuite/gcc.target/i386/pr13685.c
Modified:
    branches/gcc-4_1-branch/gcc/ChangeLog
    branches/gcc-4_1-branch/gcc/config/i386/i386.c
    branches/gcc-4_1-branch/gcc/testsuite/ChangeLog


-- 


http://gcc.gnu.org/bugzilla/show_bug.cgi?id=13685

[Bug target/13685] Building simple test application with -march=pentium3 -Os gives SIGSEGV (unaligned sse instruction)

[jason at gcc dot gnu dot org]

------- Comment #24 from jason at gcc dot gnu dot org  2006-09-22 22:42 -------
This has been fixed for a while.


-- 

jason at gcc dot gnu dot org changed:

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


http://gcc.gnu.org/bugzilla/show_bug.cgi?id=13685

[Bug target/13685] Building simple test application with -march=pentium3 -Os gives SIGSEGV (unaligned sse instruction)

[vapier at gentoo dot org]

------- Comment #25 from vapier at gentoo dot org  2006-09-22 22:54 -------
is forcing the alignment to an even larger value really the fix ?  is there no
way to do such things on the fly ?  after all, if someone turns around and
tries to do a custom alignment on the stack that is larger than 16 bytes, that
will fail (but i guess this issue will be handled at PR28069 ?)


-- 


http://gcc.gnu.org/bugzilla/show_bug.cgi?id=13685

[Bug target/13685] Building simple test application with -march=pentium3 -Os gives SIGSEGV (unaligned sse instruction)

[agner at agner dot org]

------- Comment #26 from agner at agner dot org  2006-09-23 08:23 -------
Thank you for fixing this, but you need to tell the world which solution you
have chosen. Please see the discussion at the dublicate bug
http://gcc.gnu.org/bugzilla/show_bug.cgi?id=27537 for arguments for and against
each possible solution.

You need to specify whether the chosen solution is to enforce 16 byte stack
alignment regardless of -Os option or the solution is to make no assumption
about stack alignment when making XMM code. This is an ABI issue that has to be
standardized and made public. The makers of the Intel compiler are waiting for
a resolution to this issue so that they can make their compiler compatible with
GCC. For the same reason, assembly programmers need to know whether stack
alignment is required or not.


-- 


http://gcc.gnu.org/bugzilla/show_bug.cgi?id=13685

[Bug target/13685] Building simple test application with -march=pentium3 -Os gives SIGSEGV (unaligned sse instruction)

[vda dot linux at googlemail dot com]

------- Comment #27 from vda dot linux at googlemail dot com  2007-07-23 00:06 -------
May I point that alternative solution (to align stack _in the function which
needs it_) doesn't crash if called by code generated by old or new gcc, and
also  gives smaller, faster and less stack consuming code for all people who do
not do any SSE stuff?


-- 


http://gcc.gnu.org/bugzilla/show_bug.cgi?id=13685