`MaskedPrototype` is initialized and used nowhere, this is a bug. The
existing codebase works correctly upon this bug because the default
policy for unmasked intrinsics is set to TAMU.
The existing code works because the default policy for unmasked
intrinsics is set to TAMU. This is something to be fixed because when
the default policy is changed to TAMA, clang will generate incorrect
result.
This is the 9th commit of a patch-set that aims to change the default policy
for RVV intrinsics from TAMU to TAMA.
Please refer to the cover letter in the 1st commit (D141573) for an
overview.