[FFmpeg-devel] [PATCH 1/4] tests/checkasm: add overflow test for hevc_add_res

[Fu, Linjie]

> -----Original Message-----
> From: ffmpeg-devel <ffmpeg-devel-bounces at ffmpeg.org> On Behalf Of
> Michael Niedermayer
> Sent: Wednesday, March 4, 2020 02:41
> To: FFmpeg development discussions and patches <ffmpeg-
> devel at ffmpeg.org>
> Subject: Re: [FFmpeg-devel] [PATCH 1/4] tests/checkasm: add overflow test
> for hevc_add_res
> 
> On Wed, Dec 11, 2019 at 04:45:36PM +0800, Linjie Fu wrote:
> > Add overflow test for hevc_add_res when int16_t coeff = -32768.
> > The result of C is good, while ASM is not.
> >
> > To verify:
> >     make fate-checkasm-hevc_add_res
> >     ffmpeg/tests/checkasm/checkasm --test=hevc_add_res
> >
> > ./checkasm --test=hevc_add_res
> > checkasm: using random seed 679391863
> > MMXEXT:
> >     hevc_add_res_4x4_8_mmxext (hevc_add_res.c:69)
> >   - hevc_add_res.add_residual [FAILED]
> > SSE2:
> >     hevc_add_res_8x8_8_sse2 (hevc_add_res.c:69)
> >     hevc_add_res_16x16_8_sse2 (hevc_add_res.c:69)
> >     hevc_add_res_32x32_8_sse2 (hevc_add_res.c:69)
> >   - hevc_add_res.add_residual [FAILED]
> > AVX:
> >     hevc_add_res_8x8_8_avx (hevc_add_res.c:69)
> >     hevc_add_res_16x16_8_avx (hevc_add_res.c:69)
> >     hevc_add_res_32x32_8_avx (hevc_add_res.c:69)
> >   - hevc_add_res.add_residual [FAILED]
> > AVX2:
> >     hevc_add_res_32x32_8_avx2 (hevc_add_res.c:69)
> >   - hevc_add_res.add_residual [FAILED]
> > checkasm: 8 of 14 tests have failed
> >
> > Signed-off-by: Xu Guangxin <guangxin.xu at intel.com>
> > Signed-off-by: Linjie Fu <linjie.fu at intel.com>
> > ---
> >  tests/checkasm/hevc_add_res.c | 1 +
> >  1 file changed, 1 insertion(+)
> >
> > diff --git a/tests/checkasm/hevc_add_res.c
> b/tests/checkasm/hevc_add_res.c
> > index e92c6b4..a6e3b8a 100644
> > --- a/tests/checkasm/hevc_add_res.c
> > +++ b/tests/checkasm/hevc_add_res.c
> > @@ -58,6 +58,7 @@ static void check_add_res(HEVCDSPContext h, int
> bit_depth)
> >
> >          randomize_buffers(res0, size);
> >          randomize_buffers2(dst0, size);
> > +        res0[0] = 0x8000;// overflow test
> >          memcpy(res1, res0, sizeof(*res0) * size);
> >          memcpy(dst1, dst0, sizeof(int16_t) * size);
> 
> unconditionally and always seting this would reduce the space that can
> be tested unless iam missing something

Thanks and Yes it could be a problem especially for 4x4 tests since it only
has 16 residual tested in total (if we set 1 constant test for overflow)

To cover the overflow situation without reducing the testing space, one
simple way is to add one more check for checkasm_hevc_add_res to test
2x cases (no too much cost introduced):

@@ -80,6 +81,7 @@ void checkasm_check_hevc_add_res(void)

         ff_hevc_dsp_init(&h, bit_depth);
         check_add_res(h, bit_depth);
+        check_add_res(h, bit_depth);

If it's suitable, I'll update and resend the patch set.
(also there may be another choice to only apply the fix in patch 2 ~ 4)

Looking forward to your further comments.

- Linjie