https://gcc.gnu.org/bugzilla/show_bug.cgi?id=104723
--- Comment #9 from cuilili <lili.cui at intel dot com> ---
(In reply to cuilili from comment #3)
> (In reply to Hongtao.liu from comment #1)
> > STF issue here?
>
correct comment #3
I used perf to collect the "ld_blocks.store_forward" event for those two test
cases, stlf_64_55_64.S has STLF issue due to the two stores overlapping, not
related to crossing cache line.
In this case it has STLF issue.
----------------------------------------------------------------
$cat stlf_64_55_64.S
...
.LFB0:
.cfi_startproc
vmovdqu %ymm0, -64(%rsp)
vmovdqu %ymm1, -55(%rsp)
vmovdqu -64(%rsp), %ymm0
ret
.cfi_endproc
...
$ perf stat -e ld_blocks.store_forward ./stlf_64_55_64.out
runtime= : 128883744
Performance counter stats for './stlf_64_55_64.out':
10,000,507 ld_blocks.store_forward:u
----------------------------------------------------------------
In this case it can do STLF.
----------------------------------------------------------------
$ cat stlf_64_128_64.S
...
.LFB0:
.cfi_startproc
vmovdqu %ymm0, -64(%rsp)
vmovdqu %ymm1, -128(%rsp)
vmovdqu -64(%rsp), %ymm0
ret
.cfi_endproc
...
$ perf stat -e ld_blocks.store_forward ./stlf_64_128_64.out
runtime= : 56477424
Performance counter stats for './stlf_64_128_64.out':
2 ld_blocks.store_forward:u
0.022103902 seconds time elapsed
-------------------------------------------------------------
