https://gcc.gnu.org/bugzilla/show_bug.cgi?id=104401
Bug ID: 104401
Summary: [x86] Failure to recognize min/max pattern using
pcmp+pblendv
Product: gcc
Version: 12.0
Status: UNCONFIRMED
Severity: normal
Priority: P3
Component: target
Assignee: unassigned at gcc dot gnu.org
Reporter: gabravier at gmail dot com
Target Milestone: ---
#include <smmintrin.h>
__m128i min32(__m128i value, __m128i input)
{
return _mm_blendv_epi8(input, value, _mm_cmplt_epi32(value, input));
}
With -O3 -msse4.1, GCC outputs this:
min32(long long __vector(2), long long __vector(2)):
movdqa xmm2, xmm0
movdqa xmm0, xmm1
movdqa xmm3, xmm1
pcmpgtd xmm0, xmm2
pblendvb xmm3, xmm2, xmm0
movdqa xmm0, xmm3
ret
LLVM instead outputs this:
min32(long long __vector(2), long long __vector(2)):
pminsd xmm0, xmm1
ret
The equivalent code with cmpgt used instead of cmplt can be optimized to
pmaxsd.
