SH4 optimizations have been removed in
commit d6096a67422534918405abb46dafbbac4608cbc3
The last revission with the optimizations is cbfc9046e1c7e295b74f252902ae6f255eef4e78

If you want to maintain these (or other) SH4 optimizations in ffmpeg, then please
contact ffmpeg-devel@ffmpeg.org