[FFmpeg-trac] #11306(undetermined:new): fate-rv40 fails on RVV

[FFmpeg]

#11306: fate-rv40 fails on RVV
-------------------------------------+-------------------------------------
             Reporter:  Rémi Denis-  |                     Type:  defect
  Courmont                           |
               Status:  new          |                 Priority:  normal
            Component:               |                  Version:
  undetermined                       |  unspecified
             Keywords:               |               Blocked By:
             Blocking:               |  Reproduced by developer:  0
Analyzed by developer:  0            |
-------------------------------------+-------------------------------------
 Summary of the bug:
 How to reproduce:
 {{{
 % make fate-rv40
 }}}

 Bissection leads to this:
 ```
 95d1052fba671d6c4ab6727a6905a637d03211c7 is the first bad commit
 commit 95d1052fba671d6c4ab6727a6905a637d03211c7 (HEAD)
 Author: Rémi Denis-Courmont <remi at remlab.net>
 Date:   Sat Nov 18 22:09:57 2023 +0200

     lavu/riscv: add hwprobe() for CPU detection

     This adds the Linux-specific function call to detect CPU features.
 Unlike
     the more portable auxillary vector, this supports extensions other
 than
     single lettered ones. At this point, FFmpeg already needs this to
 detect
     Zba and Zbb at run-time, and probably will need it for Zvbb in the
 near
     future.

     Support will be available in glibc 2.40 onward.

  configure             |  3 +++
  libavutil/riscv/cpu.c | 25 +++++++++++++++++++++++++
  2 files changed, 28 insertions(+)
 ```
 This commit is ostensibly a scape-goat. The broken optimisation presumably
 depends on the Bitmap extension, and was disabled in previous commits.
-- 
Ticket URL: <https://trac.ffmpeg.org/ticket/11306>
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