On Sun, Feb 11, 2024 at 5:00 PM Andreas Rheinhardt < andreas.rheinha...@outlook.com> wrote:
> Nuo Mi: > > It's a false positive. We use -1 to index an array, but it's not > actually used. > > This patch will make the "GCC UndefinedBehaviorSanitizer" happy. > > > > Found by: checkasm-hevc_pel in > https://fate.ffmpeg.org/report.cgi?time=20240211011905&slot=x86_64-archlinux-gcc-ubsan > > Reported-by: James Almer <jamr...@gmail.com> > > --- > > libavcodec/hevcdsp_template.c | 6 +++--- > > libavcodec/x86/hevcdsp_init.c | 6 +++--- > > 2 files changed, 6 insertions(+), 6 deletions(-) > > > > diff --git a/libavcodec/hevcdsp_template.c > b/libavcodec/hevcdsp_template.c > > index 9b48bdf08e..a4b8901e5d 100644 > > --- a/libavcodec/hevcdsp_template.c > > +++ b/libavcodec/hevcdsp_template.c > > @@ -301,9 +301,9 @@ IDCT_DC(32) > > // > > > //////////////////////////////////////////////////////////////////////////////// > > #define ff_hevc_pel_filters ff_hevc_qpel_filters > > -#define DECL_HV_FILTER(f) \ > > - const uint8_t *hf = ff_hevc_ ## f ## _filters[mx - 1]; \ > > - const uint8_t *vf = ff_hevc_ ## f ## _filters[my - 1]; > > +#define DECL_HV_FILTER(f) > \ > > + const uint8_t *hf = mx ? ff_hevc_ ## f ## _filters[mx - 1] : NULL; > \ > > + const uint8_t *vf = my ? ff_hevc_ ## f ## _filters[my - 1] : NULL; > > > > #define FW_PUT(p, f, t) > \ > > static void FUNC(put_hevc_## f)(int16_t *dst, const uint8_t *src, > ptrdiff_t srcstride, int height, \ > > diff --git a/libavcodec/x86/hevcdsp_init.c > b/libavcodec/x86/hevcdsp_init.c > > index 31e81eb11f..e0f65177c4 100644 > > --- a/libavcodec/x86/hevcdsp_init.c > > +++ b/libavcodec/x86/hevcdsp_init.c > > @@ -87,9 +87,9 @@ IDCT_FUNCS(avx) > > > > > > #define ff_hevc_pel_filters ff_hevc_qpel_filters > > -#define DECL_HV_FILTER(f) \ > > - const uint8_t *hf = ff_hevc_ ## f ## _filters[mx - 1]; \ > > - const uint8_t *vf = ff_hevc_ ## f ## _filters[my - 1]; > > +#define DECL_HV_FILTER(f) > \ > > + const uint8_t *hf = mx ? ff_hevc_ ## f ## _filters[mx - 1] : NULL; > \ > > + const uint8_t *vf = my ? ff_hevc_ ## f ## _filters[my - 1] : NULL; > \ > > Spurious addition of trailing '\'. oh, you are so careful > > > > > #define FW_PUT(p, a, b, depth, opt) \ > > void ff_hevc_put_hevc_ ## a ## _ ## depth ## _##opt(int16_t *dst, const > uint8_t *src, ptrdiff_t srcstride, \ > > I have just sent an alternative solution for this that avoids all these > branches (which the compiler will not be able to eliminate). > Think about it for about 3 seconds, then give up :) 👍 > Unfortunately I can't test mips and loongarch myself; there is a > fate-runner for the latter, but nothing for the former. So hopefully > someone can test mips. > > - Andreas > > PS: The aarch64 code (hevcdsp_[eq]pel_neon.S) already offsets its > filters via dummy arrays. I wonder whether it could now reuse the > ordinary ones. > > _______________________________________________ > ffmpeg-devel mailing list > ffmpeg-devel@ffmpeg.org > https://ffmpeg.org/mailman/listinfo/ffmpeg-devel > > To unsubscribe, visit link above, or email > ffmpeg-devel-requ...@ffmpeg.org with subject "unsubscribe". > _______________________________________________ ffmpeg-devel mailing list ffmpeg-devel@ffmpeg.org https://ffmpeg.org/mailman/listinfo/ffmpeg-devel To unsubscribe, visit link above, or email ffmpeg-devel-requ...@ffmpeg.org with subject "unsubscribe".
