[FFmpeg-devel] [PATCH 3/4] checkasm: hevc_pel: Use helpers for checking for writes out of bounds

[Martin Storsjö]

On Wed, 26 Mar 2025, Martin Storsjö wrote:

> This allows catching whether the functions write outside of
> the designated rectangle, and if run with "checkasm -v", it also
> prints out on which side of the rectangle the overwrite was.
> ---
> tests/checkasm/hevc_pel.c | 157 ++++++++++++++++++++++----------------
> 1 file changed, 90 insertions(+), 67 deletions(-)

This patch exposes existing issues in the Loongson HEVC simd; running with 
"checkasm --test=hevc_pel -v" after applying these patches, shows the 
following errors:

LSX:
  - hevc_pel.qpel       [OK]
  - hevc_pel.qpel_uni   [OK]
  - hevc_pel.qpel_uni_w [OK]
    put_hevc_pel_bi_pixels12_8_lsx (src/tests/checkasm/hevc_pel.c:272)
dst (12x12):
  overwrite below
  - hevc_pel.qpel_bi    [FAILED]
  - hevc_pel.epel       [OK]
    put_hevc_epel_uni_v24_8_lsx (src/tests/checkasm/hevc_pel.c:433)
dst (24x24):
  overwrite below
    put_hevc_epel_uni_hv12_8_lsx (src/tests/checkasm/hevc_pel.c:433)
dst (12x12):
  overwrite below
  - hevc_pel.epel_uni   [FAILED]
  - hevc_pel.epel_uni_w [OK]
    put_hevc_epel_bi_hv6_8_lsx (src/tests/checkasm/hevc_pel.c:545)
dst (6x6):
  overwrite below
  - hevc_pel.epel_bi    [FAILED]
LASX:
  - hevc_pel.qpel_uni   [OK]
  - hevc_pel.qpel_uni_w [OK]
  - hevc_pel.epel_uni_w [OK]
  - hevc_pel.epel_bi    [OK]
checkasm: 4 of 231 tests have failed


So the functions seem to produce more output rows than requested, for 
"uneven" heights like 6, 12 or 24 pixels.

Can someone from Loongson please have a look at this?

We don't seem to have any Loongson instances on fate, so can I go ahead 
and push this, without waiting for the Loongson assembly to be fixed? We 
do have some on patchwork though, so I guess that'll make patchwork noisy 
for everybody else until it is fixed, so I guess I'll have to hold off of 
this patch until it is fixed.

// Martin