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* [Bug target/54703] New: [miscompilation] _mm_sub_pd is incorrectly substituted with vandnps
@ 2012-09-25 13:29 kretz at kde dot org
2012-09-25 13:32 ` [Bug target/54703] " kretz at kde dot org
` (11 more replies)
0 siblings, 12 replies; 13+ messages in thread
From: kretz at kde dot org @ 2012-09-25 13:29 UTC (permalink / raw)
To: gcc-bugs
http://gcc.gnu.org/bugzilla/show_bug.cgi?id=54703
Bug #: 54703
Summary: [miscompilation] _mm_sub_pd is incorrectly substituted
with vandnps
Classification: Unclassified
Product: gcc
Version: 4.8.0
Status: UNCONFIRMED
Severity: major
Priority: P3
Component: target
AssignedTo: unassigned@gcc.gnu.org
ReportedBy: kretz@kde.org
The following testcase:
#include <xmmintrin.h>
__attribute__((aligned(16))) static const unsigned long long mask[2] = {
0xffffffffff000000ull, 0xffffffffff000000ull };
inline __m128d foo(__m128d v1) {
const __m128d h1 = _mm_and_pd(v1, _mm_load_pd(reinterpret_cast<const double
*>(&mask)));
const __m128d l1 = _mm_sub_pd(v1, h1);
return _mm_mul_pd(h1, l1);
}
__m128d test() {
__m128d a = _mm_set1_pd(2.);
return foo(foo(a));
}
compiles to
.cfi_startproc
vmovaps _ZL4mask(%rip), %xmm0
vandps .LC0(%rip), %xmm0, %xmm2
vandnps .LC0(%rip), %xmm0, %xmm1
vmulpd %xmm1, %xmm2, %xmm1
vandps %xmm0, %xmm1, %xmm0
vsubpd %xmm0, %xmm1, %xmm1
vmulpd %xmm1, %xmm0, %xmm0
ret
.cfi_endproc
The second foo call is correct: vandps and vsubpd are used. But the first call
uses vandps and vandnps. This pattern would be correct for integers, but is
obviously wrong for floating point numbers.
^ permalink raw reply [flat|nested] 13+ messages in thread
* [Bug target/54703] [miscompilation] _mm_sub_pd is incorrectly substituted with vandnps
2012-09-25 13:29 [Bug target/54703] New: [miscompilation] _mm_sub_pd is incorrectly substituted with vandnps kretz at kde dot org
@ 2012-09-25 13:32 ` kretz at kde dot org
2012-09-25 13:48 ` [Bug target/54703] " rguenth at gcc dot gnu.org
` (10 subsequent siblings)
11 siblings, 0 replies; 13+ messages in thread
From: kretz at kde dot org @ 2012-09-25 13:32 UTC (permalink / raw)
To: gcc-bugs
http://gcc.gnu.org/bugzilla/show_bug.cgi?id=54703
--- Comment #1 from Matthias Kretz <kretz at kde dot org> 2012-09-25 13:32:27 UTC ---
Um, sorry. Forgot to note the compiler switches:
gcc -O1 -march=bdver1
I can't reproduce the error with corei7-avx or any other non-AVX target.
^ permalink raw reply [flat|nested] 13+ messages in thread
* [Bug target/54703] _mm_sub_pd is incorrectly substituted with vandnps
2012-09-25 13:29 [Bug target/54703] New: [miscompilation] _mm_sub_pd is incorrectly substituted with vandnps kretz at kde dot org
2012-09-25 13:32 ` [Bug target/54703] " kretz at kde dot org
@ 2012-09-25 13:48 ` rguenth at gcc dot gnu.org
2012-09-25 13:48 ` jakub at gcc dot gnu.org
` (9 subsequent siblings)
11 siblings, 0 replies; 13+ messages in thread
From: rguenth at gcc dot gnu.org @ 2012-09-25 13:48 UTC (permalink / raw)
To: gcc-bugs
http://gcc.gnu.org/bugzilla/show_bug.cgi?id=54703
Richard Guenther <rguenth at gcc dot gnu.org> changed:
What |Removed |Added
----------------------------------------------------------------------------
Keywords| |wrong-code
Target| |x86_64-*-*, i?86-*-*
Status|UNCONFIRMED |NEW
Last reconfirmed| |2012-09-25
Summary|[miscompilation] _mm_sub_pd |_mm_sub_pd is incorrectly
|is incorrectly substituted |substituted with vandnps
|with vandnps |
Ever Confirmed|0 |1
--- Comment #2 from Richard Guenther <rguenth at gcc dot gnu.org> 2012-09-25 13:47:48 UTC ---
Confirmed.
^ permalink raw reply [flat|nested] 13+ messages in thread
* [Bug target/54703] _mm_sub_pd is incorrectly substituted with vandnps
2012-09-25 13:29 [Bug target/54703] New: [miscompilation] _mm_sub_pd is incorrectly substituted with vandnps kretz at kde dot org
2012-09-25 13:32 ` [Bug target/54703] " kretz at kde dot org
2012-09-25 13:48 ` [Bug target/54703] " rguenth at gcc dot gnu.org
@ 2012-09-25 13:48 ` jakub at gcc dot gnu.org
2012-09-25 14:30 ` jakub at gcc dot gnu.org
` (8 subsequent siblings)
11 siblings, 0 replies; 13+ messages in thread
From: jakub at gcc dot gnu.org @ 2012-09-25 13:48 UTC (permalink / raw)
To: gcc-bugs
http://gcc.gnu.org/bugzilla/show_bug.cgi?id=54703
--- Comment #3 from Jakub Jelinek <jakub at gcc dot gnu.org> 2012-09-25 13:48:10 UTC ---
Looking into it.
^ permalink raw reply [flat|nested] 13+ messages in thread
* [Bug target/54703] _mm_sub_pd is incorrectly substituted with vandnps
2012-09-25 13:29 [Bug target/54703] New: [miscompilation] _mm_sub_pd is incorrectly substituted with vandnps kretz at kde dot org
` (2 preceding siblings ...)
2012-09-25 13:48 ` jakub at gcc dot gnu.org
@ 2012-09-25 14:30 ` jakub at gcc dot gnu.org
2012-09-25 14:35 ` jakub at gcc dot gnu.org
` (7 subsequent siblings)
11 siblings, 0 replies; 13+ messages in thread
From: jakub at gcc dot gnu.org @ 2012-09-25 14:30 UTC (permalink / raw)
To: gcc-bugs
http://gcc.gnu.org/bugzilla/show_bug.cgi?id=54703
Jakub Jelinek <jakub at gcc dot gnu.org> changed:
What |Removed |Added
----------------------------------------------------------------------------
CC| |jakub at gcc dot gnu.org
Target Milestone|--- |4.6.4
^ permalink raw reply [flat|nested] 13+ messages in thread
* [Bug target/54703] _mm_sub_pd is incorrectly substituted with vandnps
2012-09-25 13:29 [Bug target/54703] New: [miscompilation] _mm_sub_pd is incorrectly substituted with vandnps kretz at kde dot org
` (3 preceding siblings ...)
2012-09-25 14:30 ` jakub at gcc dot gnu.org
@ 2012-09-25 14:35 ` jakub at gcc dot gnu.org
2012-09-25 18:04 ` pinskia at gcc dot gnu.org
` (6 subsequent siblings)
11 siblings, 0 replies; 13+ messages in thread
From: jakub at gcc dot gnu.org @ 2012-09-25 14:35 UTC (permalink / raw)
To: gcc-bugs
http://gcc.gnu.org/bugzilla/show_bug.cgi?id=54703
Jakub Jelinek <jakub at gcc dot gnu.org> changed:
What |Removed |Added
----------------------------------------------------------------------------
Status|NEW |ASSIGNED
AssignedTo|unassigned at gcc dot |jakub at gcc dot gnu.org
|gnu.org |
--- Comment #4 from Jakub Jelinek <jakub at gcc dot gnu.org> 2012-09-25 14:34:32 UTC ---
Created attachment 28270
--> http://gcc.gnu.org/bugzilla/attachment.cgi?id=28270
gcc48-pr54703.patch
Untested fix.
^ permalink raw reply [flat|nested] 13+ messages in thread
* [Bug target/54703] _mm_sub_pd is incorrectly substituted with vandnps
2012-09-25 13:29 [Bug target/54703] New: [miscompilation] _mm_sub_pd is incorrectly substituted with vandnps kretz at kde dot org
` (4 preceding siblings ...)
2012-09-25 14:35 ` jakub at gcc dot gnu.org
@ 2012-09-25 18:04 ` pinskia at gcc dot gnu.org
2012-09-25 21:57 ` jakub at gcc dot gnu.org
` (5 subsequent siblings)
11 siblings, 0 replies; 13+ messages in thread
From: pinskia at gcc dot gnu.org @ 2012-09-25 18:04 UTC (permalink / raw)
To: gcc-bugs
http://gcc.gnu.org/bugzilla/show_bug.cgi?id=54703
--- Comment #5 from Andrew Pinski <pinskia at gcc dot gnu.org> 2012-09-25 18:04:00 UTC ---
(In reply to comment #4)
> Created attachment 28270 [details]
> gcc48-pr54703.patch
Since I wrote the code which breaks this, this looks good. The only question I
have is why is AND allowed on non integer types anyways?
^ permalink raw reply [flat|nested] 13+ messages in thread
* [Bug target/54703] _mm_sub_pd is incorrectly substituted with vandnps
2012-09-25 13:29 [Bug target/54703] New: [miscompilation] _mm_sub_pd is incorrectly substituted with vandnps kretz at kde dot org
` (5 preceding siblings ...)
2012-09-25 18:04 ` pinskia at gcc dot gnu.org
@ 2012-09-25 21:57 ` jakub at gcc dot gnu.org
2012-09-26 10:53 ` kretz at kde dot org
` (4 subsequent siblings)
11 siblings, 0 replies; 13+ messages in thread
From: jakub at gcc dot gnu.org @ 2012-09-25 21:57 UTC (permalink / raw)
To: gcc-bugs
http://gcc.gnu.org/bugzilla/show_bug.cgi?id=54703
--- Comment #6 from Jakub Jelinek <jakub at gcc dot gnu.org> 2012-09-25 21:56:53 UTC ---
Yeah, the generic code is not buggy, it seems sane to assume AND is
integral/vector integer operation only, but I think i?86 isn't the only backend
that uses AND on vector floating point modes extensively.
^ permalink raw reply [flat|nested] 13+ messages in thread
* [Bug target/54703] _mm_sub_pd is incorrectly substituted with vandnps
2012-09-25 13:29 [Bug target/54703] New: [miscompilation] _mm_sub_pd is incorrectly substituted with vandnps kretz at kde dot org
` (6 preceding siblings ...)
2012-09-25 21:57 ` jakub at gcc dot gnu.org
@ 2012-09-26 10:53 ` kretz at kde dot org
2012-09-27 10:48 ` jakub at gcc dot gnu.org
` (3 subsequent siblings)
11 siblings, 0 replies; 13+ messages in thread
From: kretz at kde dot org @ 2012-09-26 10:53 UTC (permalink / raw)
To: gcc-bugs
http://gcc.gnu.org/bugzilla/show_bug.cgi?id=54703
--- Comment #7 from Matthias Kretz <kretz at kde dot org> 2012-09-26 10:52:38 UTC ---
Thanks for the quick response! You guys are cool! :)
The pattern here is for calculation with extended precision:
xh = x & mask;
xl = x - xh;
yh = y & mask
yl = y - yh;
/* x * y + small = */ xh * yh + ((xh * yl + xl * yh) + (xl * yl + small));
Other than that, yes there's a lot of ANDPS is SSE code, just this pattern
which gets miscompiled is not very common.
^ permalink raw reply [flat|nested] 13+ messages in thread
* [Bug target/54703] _mm_sub_pd is incorrectly substituted with vandnps
2012-09-25 13:29 [Bug target/54703] New: [miscompilation] _mm_sub_pd is incorrectly substituted with vandnps kretz at kde dot org
` (7 preceding siblings ...)
2012-09-26 10:53 ` kretz at kde dot org
@ 2012-09-27 10:48 ` jakub at gcc dot gnu.org
2012-09-27 10:54 ` jakub at gcc dot gnu.org
` (2 subsequent siblings)
11 siblings, 0 replies; 13+ messages in thread
From: jakub at gcc dot gnu.org @ 2012-09-27 10:48 UTC (permalink / raw)
To: gcc-bugs
http://gcc.gnu.org/bugzilla/show_bug.cgi?id=54703
--- Comment #8 from Jakub Jelinek <jakub at gcc dot gnu.org> 2012-09-27 10:48:14 UTC ---
Author: jakub
Date: Thu Sep 27 10:48:07 2012
New Revision: 191801
URL: http://gcc.gnu.org/viewcvs?root=gcc&view=rev&rev=191801
Log:
PR target/54703
* simplify-rtx.c (simplify_binary_operation_1): Perform
(x - (x & y)) -> (x & ~y) optimization only for integral
modes.
* gcc.target/i386/pr54703.c: New test.
Added:
trunk/gcc/testsuite/gcc.target/i386/pr54703.c
Modified:
trunk/gcc/ChangeLog
trunk/gcc/simplify-rtx.c
trunk/gcc/testsuite/ChangeLog
^ permalink raw reply [flat|nested] 13+ messages in thread
* [Bug target/54703] _mm_sub_pd is incorrectly substituted with vandnps
2012-09-25 13:29 [Bug target/54703] New: [miscompilation] _mm_sub_pd is incorrectly substituted with vandnps kretz at kde dot org
` (8 preceding siblings ...)
2012-09-27 10:48 ` jakub at gcc dot gnu.org
@ 2012-09-27 10:54 ` jakub at gcc dot gnu.org
2012-09-27 10:54 ` jakub at gcc dot gnu.org
2013-04-12 16:29 ` jakub at gcc dot gnu.org
11 siblings, 0 replies; 13+ messages in thread
From: jakub at gcc dot gnu.org @ 2012-09-27 10:54 UTC (permalink / raw)
To: gcc-bugs
http://gcc.gnu.org/bugzilla/show_bug.cgi?id=54703
Jakub Jelinek <jakub at gcc dot gnu.org> changed:
What |Removed |Added
----------------------------------------------------------------------------
Known to work| |4.7.3, 4.8.0
Known to fail|4.8.0 |
--- Comment #10 from Jakub Jelinek <jakub at gcc dot gnu.org> 2012-09-27 10:54:36 UTC ---
Fixed for 4.7.3+ so far.
^ permalink raw reply [flat|nested] 13+ messages in thread
* [Bug target/54703] _mm_sub_pd is incorrectly substituted with vandnps
2012-09-25 13:29 [Bug target/54703] New: [miscompilation] _mm_sub_pd is incorrectly substituted with vandnps kretz at kde dot org
` (9 preceding siblings ...)
2012-09-27 10:54 ` jakub at gcc dot gnu.org
@ 2012-09-27 10:54 ` jakub at gcc dot gnu.org
2013-04-12 16:29 ` jakub at gcc dot gnu.org
11 siblings, 0 replies; 13+ messages in thread
From: jakub at gcc dot gnu.org @ 2012-09-27 10:54 UTC (permalink / raw)
To: gcc-bugs
http://gcc.gnu.org/bugzilla/show_bug.cgi?id=54703
--- Comment #9 from Jakub Jelinek <jakub at gcc dot gnu.org> 2012-09-27 10:53:47 UTC ---
Author: jakub
Date: Thu Sep 27 10:53:42 2012
New Revision: 191802
URL: http://gcc.gnu.org/viewcvs?root=gcc&view=rev&rev=191802
Log:
PR target/54703
* simplify-rtx.c (simplify_binary_operation_1): Perform
(x - (x & y)) -> (x & ~y) optimization only for integral
modes.
* gcc.target/i386/pr54703.c: New test.
Added:
branches/gcc-4_7-branch/gcc/testsuite/gcc.target/i386/pr54703.c
Modified:
branches/gcc-4_7-branch/gcc/ChangeLog
branches/gcc-4_7-branch/gcc/simplify-rtx.c
branches/gcc-4_7-branch/gcc/testsuite/ChangeLog
^ permalink raw reply [flat|nested] 13+ messages in thread
* [Bug target/54703] _mm_sub_pd is incorrectly substituted with vandnps
2012-09-25 13:29 [Bug target/54703] New: [miscompilation] _mm_sub_pd is incorrectly substituted with vandnps kretz at kde dot org
` (10 preceding siblings ...)
2012-09-27 10:54 ` jakub at gcc dot gnu.org
@ 2013-04-12 16:29 ` jakub at gcc dot gnu.org
11 siblings, 0 replies; 13+ messages in thread
From: jakub at gcc dot gnu.org @ 2013-04-12 16:29 UTC (permalink / raw)
To: gcc-bugs
http://gcc.gnu.org/bugzilla/show_bug.cgi?id=54703
Jakub Jelinek <jakub at gcc dot gnu.org> changed:
What |Removed |Added
----------------------------------------------------------------------------
Status|ASSIGNED |RESOLVED
Resolution| |FIXED
Target Milestone|4.6.4 |4.7.3
--- Comment #11 from Jakub Jelinek <jakub at gcc dot gnu.org> 2013-04-12 16:29:14 UTC ---
The 4.6 branch has been closed, fixed in GCC 4.7.3.
^ permalink raw reply [flat|nested] 13+ messages in thread
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2012-09-25 13:29 [Bug target/54703] New: [miscompilation] _mm_sub_pd is incorrectly substituted with vandnps kretz at kde dot org
2012-09-25 13:32 ` [Bug target/54703] " kretz at kde dot org
2012-09-25 13:48 ` [Bug target/54703] " rguenth at gcc dot gnu.org
2012-09-25 13:48 ` jakub at gcc dot gnu.org
2012-09-25 14:30 ` jakub at gcc dot gnu.org
2012-09-25 14:35 ` jakub at gcc dot gnu.org
2012-09-25 18:04 ` pinskia at gcc dot gnu.org
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2012-09-26 10:53 ` kretz at kde dot org
2012-09-27 10:48 ` jakub at gcc dot gnu.org
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