REMAP is an advanced form of Vector "Structure Packing" that
provides hardware-level support for commonly-used *nested* loop patterns
that would otherwise require full inline loop unrolling.
-For more general reordering an Indexed REMAP mode is available.
+For more general reordering an Indexed REMAP mode is available
+(an abstracted analog to `xxperm`).
REMAP allows the usual sequential vector loop `0..VL-1` to be "reshaped" (re-mapped)
from a linear form to a 2D or 3D transposed form, or "offset" to permit