https://gcc.gnu.org/bugzilla/show_bug.cgi?id=112326
Bug ID: 112326
Summary: Redundant vsetvl in fixed-vlmax autovectorization
codes
Product: gcc
Version: 14.0
Status: UNCONFIRMED
Severity: normal
Priority: P3
Component: c
Assignee: unassigned at gcc dot gnu.org
Reporter: juzhe.zhong at rivai dot ai
Target Milestone: ---
#include <stdint.h>
void
f (int *__restrict y, int *__restrict x, int *__restrict z, int n)
{
for (int i = 0; i < n; ++i)
x[i] = y[i] + x[i];
}
--param=riscv-autovec-preference=scalable -fno-vect-cost-model:
vsetvli a5,a3,e32,m1,ta,ma
slli a2,a5,2
vle32.v v1,0(a1)
vle32.v v2,0(a0)
sub a3,a3,a5
vadd.vv v1,v1,v2
vse32.v v1,0(a4)
add a0,a0,a2
add a1,a1,a2
add a4,a4,a2
bne a3,zero,.L3
However, with --param=riscv-autovec-preference=fixed-vlmax:
vsetvli a5,a3,e8,mf4,ta,ma -> should be changed into e32m1
vle32.v v1,0(a1)
vle32.v v2,0(a0)
vsetivli zero,4,e32,m1,ta,ma -> redundant
slli a2,a5,2
vadd.vv v1,v1,v2
sub a3,a3,a5
vsetvli zero,a5,e32,m1,ta,ma -> redundant
vse32.v v1,0(a4)
add a0,a0,a2
add a1,a1,a2
add a4,a4,a2
bne a3,zero,.L3
