This PR improves the vector register groups overlap check in
widening/narrowing
instructions.
- Fix wrong illegal overlap condition between VS2 and VD vector register
groups.
- Also check VS1 vector register group for overlap with VD in
vector-vector
instructions.
- Parametrize widening/narrowing factors in overlap check function to
potentially
handle more cases.
Fixes issue #442.
82c91e8edb