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From: "kretz at kde dot org" <gcc-bugzilla@gcc.gnu.org>
To: gcc-bugs@gcc.gnu.org
Subject: [Bug target/54703] New: [miscompilation] _mm_sub_pd is incorrectly substituted with vandnps
Date: Tue, 25 Sep 2012 13:29:00 -0000 [thread overview]
Message-ID: <bug-54703-4@http.gcc.gnu.org/bugzilla/> (raw)
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.
next reply other threads:[~2012-09-25 13:29 UTC|newest]
Thread overview: 13+ messages / expand[flat|nested] mbox.gz Atom feed top
2012-09-25 13:29 kretz at kde dot org [this message]
2012-09-25 13:32 ` [Bug target/54703] " kretz at kde dot org
2012-09-25 13:48 ` [Bug target/54703] " jakub at gcc dot gnu.org
2012-09-25 13:48 ` rguenth 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
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
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
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