https://gcc.gnu.org/bugzilla/show_bug.cgi?id=110428
--- Comment #4 from JuzheZhong <juzhe.zhong at rivai dot ai> ---
(In reply to JuzheZhong from comment #3)
> Hi, I think for VLS vectors, we should be able the enhance CSE for this
> following case:
>
> #include <stdint.h>
>
> void __attribute__((noinline,noclone))
> foo (int *out, int *res, unsigned int n)
> {
> int mask[] = { 0, 1, 0, 1, 0, 1, 0, 1, 0, 1, 0, 1, 0, 1, 0, 1 };
> int i;
> for (i = 0; i < n+16; ++i)
> {
> if (mask[i])
> out[i] = i;
> }
> int o0 = out[0];
> int o7 = out[7];
> int o14 = out[14];
> int o15 = out[15];
> res[0] = o0;
> res[2] = o7;
> res[4] = o14;
> res[6] = o15;
> }
>
> since n is unsigned int number, i < n + 16, ARM SVE fail to CSE.
> Is it right?
Maybe this case is too complicated, I try this following case:
void __attribute__((noinline,noclone))
foo (int *out, int *res, unsigned int n)
{
int mask[] = { 0, 1, 0, 1, 0, 1, 0, 1, 0, 1, 0, 1, 0, 1, 0, 1 };
int i;
for (i = 0; i < 16; ++i)
{
if (mask[i])
out[i] = i;
}
for (i = 16; i < n + 16; ++i)
{
if (mask[i])
out[i] = i;
}
int o0 = out[0];
int o7 = out[7];
int o14 = out[14];
int o15 = out[15];
res[0] = o0;
res[2] = o7;
res[4] = o14;
res[6] = o15;
}
Such case is simpler, it should be CSE? I tried on SVE, GCC failed to CSE.
