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* [Bug c++/18944] New: SSE ordered/unordered compare are either omitted or provoke an ICE, -ffast-math implied
@ 2004-12-12 17:27 tbptbp at gmail dot com
2004-12-12 17:50 ` [Bug target/18944] [4.0 Regression] " pinskia at gcc dot gnu dot org
` (2 more replies)
0 siblings, 3 replies; 4+ messages in thread
From: tbptbp at gmail dot com @ 2004-12-12 17:27 UTC (permalink / raw)
To: gcc-bugs
All versions of gcc and g++ i've tested have issues with SSE ordered/unordered
compare (vector or scalar) when -ffast-math is on; the result being either an
ICE, the instruction being omitted or rarely the Right Thing.
ie with gcc/g++ 4.0.0 20041205:
#include <xmmintrin.h>
int main() {
__m128
a = _mm_set1_ps(1.f/0.f),
b = _mm_set1_ps(0),
c = _mm_mul_ps(a,b),
//z = _mm_setzero_ps(),
comp = _mm_cmpunord_ps(c,c); // ICE -O >= 1
//comp = _mm_cmpord_ps(c,c); // ok
//comp = _mm_cmpord_ps(c,z); // removed with -O >= 1
//comp = _mm_cmpunord_ps(c,z); // removed with -O >= 1
//comp = _mm_cmpunord_ss(c,c); // ok
//comp = _mm_cmpord_ss(c,c); // ok
//comp = _mm_cmpord_ss(c,z); // ok
//comp = _mm_cmpunord_ss(c,z); // ok
return _mm_movemask_ps(comp);
}
$ /usr/local/gcc-405/bin/g++ sse.cpp -march=pentium4 -O1 -ffast-math
sse.cpp: In function 'int main()':
sse.cpp:7: warning: division by zero in '1.0e+0f / 0.'
sse.cpp:21: internal compiler error: in output_constant_pool_2, at varasm.c:3108
Please submit a full bug report,
with preprocessed source if appropriate.
See <URL:http://gcc.gnu.org/bugs.html> for instructions.
$ /usr/local/gcc-405/bin/gcc -v
Reading specs from /usr/local/gcc-405/lib/gcc/i686-pc-cygwin/4.0.0/specs
Configured with: ../configure --prefix=/usr/local/gcc-405
--enable-languages=c,c++ --enable-threads=posix --with-system-zlib
--disable-checking --disable-nls --disable-shared --disable-win32-registry
--verbose --with-gcc --with-gnu-ld --with-gnu-as
--with-as=/usr/local/binutils/bin/as --with-ld=/usr/local/binutils/bin/ld
Thread model: posix
gcc version 4.0.0 20041205 (experimental)
That 20041205 snapshot is the best at handling that particular issue, it's even
worse with other version. I've tried:
gcc version 3.3.3 (cygwin special)
gcc version 3.4.1 20040625 (prerelease)
gcc version 3.5.0 20040620 (experimental)
You get the same with -march=k8.
So it's not just a gcc4.0.0 problem, i don't have older version or other
platforms to test it but i guess it would be wise to check it there too :)
--
Summary: SSE ordered/unordered compare are either omitted or
provoke an ICE, -ffast-math implied
Product: gcc
Version: 4.0.0
Status: UNCONFIRMED
Severity: critical
Priority: P2
Component: c++
AssignedTo: unassigned at gcc dot gnu dot org
ReportedBy: tbptbp at gmail dot com
CC: gcc-bugs at gcc dot gnu dot org
GCC host triplet: cygwin
http://gcc.gnu.org/bugzilla/show_bug.cgi?id=18944
^ permalink raw reply [flat|nested] 4+ messages in thread
* [Bug target/18944] [4.0 Regression] SSE ordered/unordered compare are either omitted or provoke an ICE, -ffast-math implied
2004-12-12 17:27 [Bug c++/18944] New: SSE ordered/unordered compare are either omitted or provoke an ICE, -ffast-math implied tbptbp at gmail dot com
@ 2004-12-12 17:50 ` pinskia at gcc dot gnu dot org
2004-12-12 17:57 ` pinskia at gcc dot gnu dot org
2004-12-12 17:59 ` pinskia at gcc dot gnu dot org
2 siblings, 0 replies; 4+ messages in thread
From: pinskia at gcc dot gnu dot org @ 2004-12-12 17:50 UTC (permalink / raw)
To: gcc-bugs
------- Additional Comments From pinskia at gcc dot gnu dot org 2004-12-12 17:50 -------
Reduced testcase:
typedef float __v4sf __attribute__ ((vector_size (16)));
int ffg (__v4sf __A);
int main()
{
float f = 1.f/0.f;
__v4sf __tmp = __builtin_ia32_loadss (&f);
__v4sf a = __builtin_ia32_shufps(__tmp, __tmp, 0),
comp = (__v4sf)__builtin_ia32_cmpunordps(a,a);
return ffg(comp);
}
: Search converges between 2004-01-01-trunk (#437) and 2004-01-17-trunk (#438).
--
What |Removed |Added
----------------------------------------------------------------------------
Status|UNCONFIRMED |NEW
Component|c++ |target
Ever Confirmed| |1
Keywords| |ice-on-valid-code
Last reconfirmed|0000-00-00 00:00:00 |2004-12-12 17:50:10
date| |
Summary|SSE ordered/unordered |[4.0 Regression] SSE
|compare are either omitted |ordered/unordered compare
|or provoke an ICE, -ffast- |are either omitted or
|math implied |provoke an ICE, -ffast-math
| |implied
Target Milestone|--- |4.0.0
http://gcc.gnu.org/bugzilla/show_bug.cgi?id=18944
^ permalink raw reply [flat|nested] 4+ messages in thread
* [Bug target/18944] [4.0 Regression] SSE ordered/unordered compare are either omitted or provoke an ICE, -ffast-math implied
2004-12-12 17:27 [Bug c++/18944] New: SSE ordered/unordered compare are either omitted or provoke an ICE, -ffast-math implied tbptbp at gmail dot com
2004-12-12 17:50 ` [Bug target/18944] [4.0 Regression] " pinskia at gcc dot gnu dot org
@ 2004-12-12 17:57 ` pinskia at gcc dot gnu dot org
2004-12-12 17:59 ` pinskia at gcc dot gnu dot org
2 siblings, 0 replies; 4+ messages in thread
From: pinskia at gcc dot gnu dot org @ 2004-12-12 17:57 UTC (permalink / raw)
To: gcc-bugs
------- Additional Comments From pinskia at gcc dot gnu dot org 2004-12-12 17:57 -------
It was fixed in the 3.4 branch:
: Search converges between 2004-10-10-004002-3.4 (#94) and 2004-10-11-004001-3.4 (#95).
--
http://gcc.gnu.org/bugzilla/show_bug.cgi?id=18944
^ permalink raw reply [flat|nested] 4+ messages in thread
* [Bug target/18944] [4.0 Regression] SSE ordered/unordered compare are either omitted or provoke an ICE, -ffast-math implied
2004-12-12 17:27 [Bug c++/18944] New: SSE ordered/unordered compare are either omitted or provoke an ICE, -ffast-math implied tbptbp at gmail dot com
2004-12-12 17:50 ` [Bug target/18944] [4.0 Regression] " pinskia at gcc dot gnu dot org
2004-12-12 17:57 ` pinskia at gcc dot gnu dot org
@ 2004-12-12 17:59 ` pinskia at gcc dot gnu dot org
2 siblings, 0 replies; 4+ messages in thread
From: pinskia at gcc dot gnu dot org @ 2004-12-12 17:59 UTC (permalink / raw)
To: gcc-bugs
------- Additional Comments From pinskia at gcc dot gnu dot org 2004-12-12 17:59 -------
This is a dup of bug 17767.
*** This bug has been marked as a duplicate of 17767 ***
--
What |Removed |Added
----------------------------------------------------------------------------
Status|NEW |RESOLVED
Resolution| |DUPLICATE
http://gcc.gnu.org/bugzilla/show_bug.cgi?id=18944
^ permalink raw reply [flat|nested] 4+ messages in thread
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2004-12-12 17:27 [Bug c++/18944] New: SSE ordered/unordered compare are either omitted or provoke an ICE, -ffast-math implied tbptbp at gmail dot com
2004-12-12 17:50 ` [Bug target/18944] [4.0 Regression] " pinskia at gcc dot gnu dot org
2004-12-12 17:57 ` pinskia at gcc dot gnu dot org
2004-12-12 17:59 ` pinskia at gcc dot gnu dot org
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