[Bug target/95764] New: Failure to optimize usage of _mm512_set1_epi32 to a single instruction
gabravier at gmail dot com
gcc-bugzilla@gcc.gnu.org
Fri Jun 19 10:45:49 GMT 2020
https://gcc.gnu.org/bugzilla/show_bug.cgi?id=95764
Bug ID: 95764
Summary: Failure to optimize usage of _mm512_set1_epi32 to a
single instruction
Product: gcc
Version: 11.0
Status: UNCONFIRMED
Severity: normal
Priority: P3
Component: target
Assignee: unassigned at gcc dot gnu.org
Reporter: gabravier at gmail dot com
Target Milestone: ---
__m512i f(__m512i a)
{
return (_mm512_set1_epi32(0x7FFFFFFF) & a);
}
With -O3 -mavx512f, LLVM outputs this :
.LCPI0_0:
.quad 9223372034707292159
f(long long __vector(8)):
vpandq zmm0, zmm0, qword ptr [rip + .LCPI0_0]{1to8}
ret
GCC outputs this :
f(long long __vector(8)):
mov eax, 2147483647
vpbroadcastd zmm1, eax
vpandq zmm0, zmm0, zmm1
ret
I'm not completely sure the LLVM version is better, but I'd rather file a bug
report (and be able to file one back to LLVM if I learn that GCC's code is
better) than just do nothing.
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