https://gcc.gnu.org/bugzilla/show_bug.cgi?id=98218
Bug ID: 98218
Summary: [TARGET_MMX_WITH_SSE] Miss vec_cmpmn/vcondmn expander
for 64bit vector
Product: gcc
Version: 11.0
Status: UNCONFIRMED
Severity: normal
Priority: P3
Component: target
Assignee: unassigned at gcc dot gnu.org
Reporter: crazylht at gmail dot com
Target Milestone: ---
Host: x86_64-pc-linux-gnu
Target: x86_64-*-* i?86-*-*
Refer to https://godbolt.org/z/sYE88f
cat test.c
typedef char v8qi __attribute__ ((vector_size(8)));
v8qi f1(v8qi a, v8qi b) {
return a == b;
}
gcc -O2 -msse4.1 -S
f1(char __vector(8), char __vector(8)):
pextrb edx, xmm0, 0
pextrb eax, xmm1, 0
pextrb ecx, xmm0, 1
cmp dl, al
pextrb eax, xmm1, 1
pextrb esi, xmm0, 2
setne dl
pextrb edi, xmm0, 3
pextrb r8d, xmm0, 4
sub edx, 1
cmp cl, al
pextrb eax, xmm1, 2
setne cl
pextrb r9d, xmm0, 5
movzx edx, dl
sub ecx, 1
cmp sil, al
pextrb eax, xmm1, 3
setne sil
pextrb r10d, xmm0, 6
pextrb r11d, xmm0, 7
movzx ecx, cl
sub esi, 1
cmp dil, al
pextrb eax, xmm1, 4
setne dil
movzx esi, sil
sub edi, 1
cmp r8b, al
pextrb eax, xmm1, 5
setne r8b
movzx edi, dil
sub r8d, 1
cmp r9b, al
pextrb eax, xmm1, 6
setne r9b
movzx r8d, r8b
sub r9d, 1
cmp r10b, al
pextrb eax, xmm1, 7
setne r10b
movzx r9d, r9b
sub r10d, 1
cmp r11b, al
setne al
movzx r10d, r10b
sub eax, 1
movzx eax, al
sal rax, 8
or rax, r10
sal rax, 8
or rax, r9
sal rax, 8
or rax, r8
sal rax, 8
or rax, rdi
sal rax, 8
or rax, rsi
sal rax, 8
or rax, rcx
sal rax, 8
or rax, rdx
movq xmm0, rax
ret
It should be better with
f1(char __vector(8), char __vector(8)): # @f1(char
__vector(8), char __vector(8))
pcmpeqb xmm0, xmm1
ret
