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* [Bug c/17934] New: gcc produces bad (misaligned?) sse2 code
@ 2004-10-11 16:11 terpstra at ito dot tu-darmstadt dot de
2004-10-11 16:13 ` [Bug c/17934] " terpstra at ito dot tu-darmstadt dot de
` (4 more replies)
0 siblings, 5 replies; 6+ messages in thread
From: terpstra at ito dot tu-darmstadt dot de @ 2004-10-11 16:11 UTC (permalink / raw)
To: gcc-bugs
For whatever reason, the attached program, when compiled with the options
gcc-3.4 -msse2 -O0 test.c -o test
will crash. This is not the case if -O2 is specified or -march=i686.
However, I have a larger testcase (the program this came from) which will fail
regardless of optimization flags or -march. It seems that this problem only
happens when gcc is given complicated enough code.
A quick look at it with gdb shows:
Program received signal SIGSEGV, Segmentation fault.
0x080483b0 in _mm_srli_epi32 (__A={51539607552, 51539607564}, __B=31)
at emmintrin.h:1261
1261 {
(gdb) up
#1 0x080483e3 in bar (x={4294967297, 4294967297}, y={4294967297, 4294967297})
at test.c:8
8 return _mm_sub_epi32(x, _mm_srli_epi32(y, 31));
(gdb) print &x
$1 = (__v2di *) 0xbffffa00
(gdb) down
#0 0x080483b0 in _mm_srli_epi32 (__A={51539607552, 51539607564}, __B=31)
at emmintrin.h:1261
1261 {
(gdb) print &__A
$2 = (__v2di *) 0xbffff9cc
This looks to me like the alignment has somehow gotten messed up.
--
Summary: gcc produces bad (misaligned?) sse2 code
Product: gcc
Version: 3.4.2
Status: UNCONFIRMED
Severity: normal
Priority: P2
Component: c
AssignedTo: unassigned at gcc dot gnu dot org
ReportedBy: terpstra at ito dot tu-darmstadt dot de
CC: gcc-bugs at gcc dot gnu dot org
GCC build triplet: i386-linux-gnu
GCC host triplet: i386-linux-gnu
GCC target triplet: i386-linux-gnu
http://gcc.gnu.org/bugzilla/show_bug.cgi?id=17934
^ permalink raw reply [flat|nested] 6+ messages in thread* [Bug c/17934] gcc produces bad (misaligned?) sse2 code
2004-10-11 16:11 [Bug c/17934] New: gcc produces bad (misaligned?) sse2 code terpstra at ito dot tu-darmstadt dot de
@ 2004-10-11 16:13 ` terpstra at ito dot tu-darmstadt dot de
2004-10-11 16:17 ` terpstra at ito dot tu-darmstadt dot de
` (3 subsequent siblings)
4 siblings, 0 replies; 6+ messages in thread
From: terpstra at ito dot tu-darmstadt dot de @ 2004-10-11 16:13 UTC (permalink / raw)
To: gcc-bugs
------- Additional Comments From terpstra at ito dot tu-darmstadt dot de 2004-10-11 16:13 -------
Created an attachment (id=7326)
--> (http://gcc.gnu.org/bugzilla/attachment.cgi?id=7326&action=view)
The program which demonstrates the problem
Here's what I narrowed it down to.
Compile with: gcc-3.4 -msse2 -O0 test.c -o test
./test
Segfault!
--
http://gcc.gnu.org/bugzilla/show_bug.cgi?id=17934
^ permalink raw reply [flat|nested] 6+ messages in thread* [Bug c/17934] gcc produces bad (misaligned?) sse2 code
2004-10-11 16:11 [Bug c/17934] New: gcc produces bad (misaligned?) sse2 code terpstra at ito dot tu-darmstadt dot de
2004-10-11 16:13 ` [Bug c/17934] " terpstra at ito dot tu-darmstadt dot de
@ 2004-10-11 16:17 ` terpstra at ito dot tu-darmstadt dot de
2004-10-11 17:09 ` pinskia at gcc dot gnu dot org
` (2 subsequent siblings)
4 siblings, 0 replies; 6+ messages in thread
From: terpstra at ito dot tu-darmstadt dot de @ 2004-10-11 16:17 UTC (permalink / raw)
To: gcc-bugs
------- Additional Comments From terpstra at ito dot tu-darmstadt dot de 2004-10-11 16:17 -------
Oh, and this problem doesn't occure in gcc 3.3.
However, gcc-3.3 ICEs on the larger program.
Since it at least compiles on gcc-3.4, I assume that is a different bug which
got fixed.
--
http://gcc.gnu.org/bugzilla/show_bug.cgi?id=17934
^ permalink raw reply [flat|nested] 6+ messages in thread* [Bug c/17934] gcc produces bad (misaligned?) sse2 code
2004-10-11 16:11 [Bug c/17934] New: gcc produces bad (misaligned?) sse2 code terpstra at ito dot tu-darmstadt dot de
2004-10-11 16:13 ` [Bug c/17934] " terpstra at ito dot tu-darmstadt dot de
2004-10-11 16:17 ` terpstra at ito dot tu-darmstadt dot de
@ 2004-10-11 17:09 ` pinskia at gcc dot gnu dot org
2004-10-11 17:22 ` terpstra at ito dot tu-darmstadt dot de
2004-10-11 17:26 ` pinskia at gcc dot gnu dot org
4 siblings, 0 replies; 6+ messages in thread
From: pinskia at gcc dot gnu dot org @ 2004-10-11 17:09 UTC (permalink / raw)
To: gcc-bugs
------- Additional Comments From pinskia at gcc dot gnu dot org 2004-10-11 17:09 -------
*** This bug has been marked as a duplicate of 10395 ***
--
What |Removed |Added
----------------------------------------------------------------------------
Status|UNCONFIRMED |RESOLVED
Resolution| |DUPLICATE
http://gcc.gnu.org/bugzilla/show_bug.cgi?id=17934
^ permalink raw reply [flat|nested] 6+ messages in thread* [Bug c/17934] gcc produces bad (misaligned?) sse2 code
2004-10-11 16:11 [Bug c/17934] New: gcc produces bad (misaligned?) sse2 code terpstra at ito dot tu-darmstadt dot de
` (2 preceding siblings ...)
2004-10-11 17:09 ` pinskia at gcc dot gnu dot org
@ 2004-10-11 17:22 ` terpstra at ito dot tu-darmstadt dot de
2004-10-11 17:26 ` pinskia at gcc dot gnu dot org
4 siblings, 0 replies; 6+ messages in thread
From: terpstra at ito dot tu-darmstadt dot de @ 2004-10-11 17:22 UTC (permalink / raw)
To: gcc-bugs
------- Additional Comments From terpstra at ito dot tu-darmstadt dot de 2004-10-11 17:22 -------
This bug does not in any way involve multiple threads.
In my attached test case, gcc starts with an aligned stack and screws up the
alignment by itself.
--
What |Removed |Added
----------------------------------------------------------------------------
Status|RESOLVED |UNCONFIRMED
Resolution|DUPLICATE |
http://gcc.gnu.org/bugzilla/show_bug.cgi?id=17934
^ permalink raw reply [flat|nested] 6+ messages in thread* [Bug c/17934] gcc produces bad (misaligned?) sse2 code
2004-10-11 16:11 [Bug c/17934] New: gcc produces bad (misaligned?) sse2 code terpstra at ito dot tu-darmstadt dot de
` (3 preceding siblings ...)
2004-10-11 17:22 ` terpstra at ito dot tu-darmstadt dot de
@ 2004-10-11 17:26 ` pinskia at gcc dot gnu dot org
4 siblings, 0 replies; 6+ messages in thread
From: pinskia at gcc dot gnu dot org @ 2004-10-11 17:26 UTC (permalink / raw)
To: gcc-bugs
------- Additional Comments From pinskia at gcc dot gnu dot org 2004-10-11 17:26 -------
No, the problem is that main is not aligned see that bug again.
*** This bug has been marked as a duplicate of 10395 ***
--
What |Removed |Added
----------------------------------------------------------------------------
Status|UNCONFIRMED |RESOLVED
Resolution| |DUPLICATE
http://gcc.gnu.org/bugzilla/show_bug.cgi?id=17934
^ permalink raw reply [flat|nested] 6+ messages in thread
end of thread, other threads:[~2004-10-11 17:26 UTC | newest]
Thread overview: 6+ messages (download: mbox.gz / follow: Atom feed)
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2004-10-11 16:11 [Bug c/17934] New: gcc produces bad (misaligned?) sse2 code terpstra at ito dot tu-darmstadt dot de
2004-10-11 16:13 ` [Bug c/17934] " terpstra at ito dot tu-darmstadt dot de
2004-10-11 16:17 ` terpstra at ito dot tu-darmstadt dot de
2004-10-11 17:09 ` pinskia at gcc dot gnu dot org
2004-10-11 17:22 ` terpstra at ito dot tu-darmstadt dot de
2004-10-11 17:26 ` pinskia at gcc dot gnu dot org
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