https://gcc.gnu.org/bugzilla/show_bug.cgi?id=102977
Bug ID: 102977
Summary: [GCC12 regression] vectorizer failed to generate
complex fma.
Product: gcc
Version: 12.0
Status: UNCONFIRMED
Severity: normal
Priority: P3
Component: middle-end
Assignee: unassigned at gcc dot gnu.org
Reporter: crazylht at gmail dot com
Target Milestone: ---
Target: aarch64-linux-gnu
#include<complex.h>
#include<complex.h>
void
foo (_Complex _Float16* __restrict a, _Complex _Float16* b, _Complex _Float16
*c)
{
for (int i =0 ; i != 8; i++)
a[i] += b[i] * c[i];
}
gcc11.2 generate
foo:
mov x3, 16
ptrue p1.b, all
whilelo p0.h, xzr, x3
ld1h z2.h, p0/z, [x1]
ld1h z1.h, p0/z, [x2]
ld1h z0.h, p0/z, [x0]
fcmla z0.h, p1/m, z1.h, z2.h, #0
fcmla z0.h, p1/m, z1.h, z2.h, #90
st1h z0.h, p0, [x0]
cntb x4
cnth x5
add x0, x0, x4
add x1, x1, x4
add x2, x2, x4
whilelo p0.h, x5, x3
b.none .L1
ld1h z2.h, p0/z, [x1]
ld1h z1.h, p0/z, [x2]
ld1h z0.h, p0/z, [x0]
fcmla z0.h, p1/m, z1.h, z2.h, #0
fcmla z0.h, p1/m, z1.h, z2.h, #90
st1h z0.h, p0, [x0]
.L1:
ret
current trunk
foo:
ptrue p1.h, vl8
ptrue p0.b, all
ld2h {z2.h - z3.h}, p1/z, [x1]
ld2h {z0.h - z1.h}, p1/z, [x2]
ld2h {z16.h - z17.h}, p1/z, [x0]
fmul z6.h, z0.h, z3.h
movprfx z7, z16
fmla z7.h, p0/m, z0.h, z2.h
fmla z6.h, p0/m, z1.h, z2.h
movprfx z4, z7
fmls z4.h, p0/m, z1.h, z3.h
fadd z5.h, z6.h, z17.h
st2h {z4.h - z5.h}, p1, [x0]
ret
options: -Ofast -march=armv8.3-a+sve+fp16
refer to https://godbolt.org/z/4PPKnWvc1
