https://gcc.gnu.org/bugzilla/show_bug.cgi?id=111970
--- Comment #14 from JuzheZhong <juzhe.zhong at rivai dot ai> ---
Just confirm on aarch64 QEMU, it seems that ARM SVE has the same issue as RVV.
This is the test:
#include <stdint-gcc.h>
#define TEST_LOOP(DATA_TYPE, INDEX_TYPE)
\
void __attribute__ ((noinline, noclone))
\
f_##DATA_TYPE##_##INDEX_TYPE (DATA_TYPE *restrict y, DATA_TYPE *restrict x,
\
INDEX_TYPE *restrict index)
\
{
\
for (int i = 0; i < 100; ++i)
\
{
\
y[i * 2] = x[index[i * 2]] + 1;
\
y[i * 2 + 1] = x[index[i * 2 + 1]] + 2;
\
}
\
}
TEST_LOOP (int16_t, int8_t)
#include <assert.h>
int
main (void)
{
#define RUN_LOOP(DATA_TYPE, INDEX_TYPE)
\
DATA_TYPE dest_##DATA_TYPE##_##INDEX_TYPE[202] = {0};
\
DATA_TYPE src_##DATA_TYPE##_##INDEX_TYPE[202] = {0};
\
INDEX_TYPE index_##DATA_TYPE##_##INDEX_TYPE[202] = {0};
\
for (int i = 0; i < 202; i++)
\
{
\
src_##DATA_TYPE##_##INDEX_TYPE[i]
\
= (DATA_TYPE) ((i * 19 + 735) & (sizeof (DATA_TYPE) * 7 - 1));
\
index_##DATA_TYPE##_##INDEX_TYPE[i] = (i * 7) % (55);
\
}
\
f_##DATA_TYPE##_##INDEX_TYPE (dest_##DATA_TYPE##_##INDEX_TYPE,
\
src_##DATA_TYPE##_##INDEX_TYPE,
\
index_##DATA_TYPE##_##INDEX_TYPE);
\
for (int i = 0; i < 100; i++)
\
{
\
assert (dest_##DATA_TYPE##_##INDEX_TYPE[i * 2]
\
== (src_##DATA_TYPE##_##INDEX_TYPE
\
[index_##DATA_TYPE##_##INDEX_TYPE[i * 2]]
\
+ 1));
\
assert (dest_##DATA_TYPE##_##INDEX_TYPE[i * 2 + 1]
\
== (src_##DATA_TYPE##_##INDEX_TYPE
\
[index_##DATA_TYPE##_##INDEX_TYPE[i * 2 + 1]]
\
+ 2));
\
}
RUN_LOOP (int16_t, int8_t)
return 0;
}
compile: -march=armv8-a+sve -O3 -msve-vector-bits=256 -specs=rdimon.specs
QEMU:sve-default-vector-length=256
The configuration above passed.
However, I tried -march=armv8-a+sve -O3 -msve-vector-bits=512
-fno-vect-cost-model -specs=rdimon.specs
QEMU:sve-default-vector-length=512
This configuration failed like RVV:
assertion "dest_int16_t_int8_t[i * 2] == (src_int16_t_int8_t
[index_int16_t_int8_t[i * 2]] + 1)" failed: file "tmp.c", line 52, function:
main
The reason I experiment on ARM SVE with vector-length = 512bits,
because I checked the dump IR on ARM SVE which is similiar with RVV:
https://godbolt.org/z/x74z7obYT
Hi, @Tamar. Could you double-check whether my analysis (This bug not only
happens on RVV, but also on ARM SVE) is correct or not ?
