https://gcc.gnu.org/bugzilla/show_bug.cgi?id=116691
Bug ID: 116691
Summary: RISC-V: Unexpected auto-vectorization codegen in
simple vectorization
Product: gcc
Version: 15.0
Status: UNCONFIRMED
Severity: normal
Priority: P3
Component: c
Assignee: unassigned at gcc dot gnu.org
Reporter: juzhe.zhong at rivai dot ai
Target Milestone: ---
void foo (int *__restrict a, int *__restrict b, int *__restrict c, int n) {
for (int i = 0; i < n; i++) {
c[i] = a[i] + b[i];
}
}
https://godbolt.org/z/4n3o3qcKW
GCC trunk:
foo:
ble a3,zero,.L5
csrr a4,vlenb
srli a6,a4,2
.L3:
minu a5,a3,a6
vsetvli zero,a5,e32,m1,ta,ma
vle32.v v2,0(a0)
vle32.v v1,0(a1)
mv a7,a3
add a0,a0,a4
add a1,a1,a4
sub a3,a3,a6
vadd.vv v1,v1,v2
vse32.v v1,0(a2)
add a2,a2,a4
bgtu a7,a6,.L3
.L5:
ret
GCC 14.2.0:
foo:
ble a3,zero,.L5
.L3:
vsetvli a5,a3,e32,m1,ta,ma
vle32.v v2,0(a0)
vle32.v v1,0(a1)
sub a3,a3,a5
sh2add a0,a5,a0
sh2add a1,a5,a1
vadd.vv v1,v1,v2
vse32.v v1,0(a2)
sh2add a2,a5,a2
bne a3,zero,.L3
.L5:
ret
