[Bug rtl-optimization/19274] New: temporary not eliminated in composite _mm_set_ps1
tbptbp at gmail dot com
gcc-bugzilla@gcc.gnu.org
Wed Jan 5 18:07:00 GMT 2005
Sometime the temporary in that composite intrinsic doesn't get eliminated.
Test case: -O3 -march=k8 -fomit-frame-pointer
#include <xmmintrin.h>
__m128 not_eliminated(const float f1, const float f2) {
const __m128
a = _mm_set_ps1(f1),
b = _mm_set_ps1(f2),
c = _mm_mul_ps(a, b);
return c;
}
#define broadcast(f) _mm_shuffle_ps(_mm_load_ss(&(f)),_mm_load_ss(&(f)),0)
__m128 eliminated(const float f1, const float f2) {
const __m128
a = broadcast(f1),
b = broadcast(f2),
c = _mm_mul_ps(a, b);
return c;
}
int main() { return 0; }
With gcc4-20040102 + patch http://gcc.gnu.org/bugzilla/show_bug.cgi?id=19240
(happens in older version too), i still get:
00401070 <not_eliminated(float, float)>:
401070: sub $0x10,%esp
401073: mov 0x14(%esp),%eax
401077: mov %eax,0xc(%esp)
40107b: mov 0x18(%esp),%eax
40107f: movss 0xc(%esp),%xmm0
401085: shufps $0x0,%xmm0,%xmm0
401089: mov %eax,0xc(%esp)
40108d: movss 0xc(%esp),%xmm1
401093: add $0x10,%esp
401096: shufps $0x0,%xmm1,%xmm1
40109a: mulps %xmm1,%xmm0
40109d: ret
and:
004010a0 <eliminated(float, float)>:
4010a0: movss 0x4(%esp),%xmm0
4010a6: movss 0x8(%esp),%xmm1
4010ac: shufps $0x0,%xmm0,%xmm0
4010b0: shufps $0x0,%xmm1,%xmm1
4010b4: mulps %xmm1,%xmm0
4010b7: ret
It might happens with other intrinsics, but i haven't spotted it yet :)
--
Summary: temporary not eliminated in composite _mm_set_ps1
Product: gcc
Version: 4.0.0
Status: UNCONFIRMED
Severity: normal
Priority: P2
Component: rtl-optimization
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=19274
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