[FFmpeg-devel] [PATCH 1/4] aarch64: Fix ff_hevc_put_hevc_epel_h48_8_neon_i8mm

[Martin Storsjö]

On Thu, 14 Mar 2024, J. Dekker wrote:

>
> Martin Storsjö <martin at martin.st> writes:
>
>> The first 32 elements of each row were correct, while the
>> last 16 were scrambled.
>>
>> This hasn't been noticed, because the checkasm test erroneously
>> only checked half of the output (for 8 bit functions), and
>> apparently none of the samples as part of "fate-hevc" seem to
>> trigger this specific function.
>> ---
>>  libavcodec/aarch64/hevcdsp_epel_neon.S | 14 +++++++++-----
>>  1 file changed, 9 insertions(+), 5 deletions(-)
>
> Thanks for the fixes, wonder if we should use checkasm_check()
> exclusively in checkasm rather than memcmp(), would probably be useful.

Wherever it makes sense and works, then yes, using checkasm_check() 
probably is useful. (Within dav1d, we use it in most tests except for a 
few.)

FWIW, many checkasm tests seem to have pretty naive setups, where e.g. all 
rows are tightly packed. If they'd use a bigger stride with more padding 
between rows, one can also detect some other cases of potential asm bugs.

> Pushed set

Thanks!

// Martin