Originally I tried spliting these features in the compiler with
https://github.com/llvm/llvm-project/pull/101712, but we decided to lump
those features in the ACLE specification (see
https://github.com/ARM-software/acle/pull/346). Since there are no
hardware implementations out there which implement ls64 without ls64_v
or ls64_accdata, this shouldn't be a regression for feature detection.
d497f465df