Does this approach make sense in general? If it does I can probably come up with more measurements.
Sounds good to me-not sure why there hasn't been more response to this, it seems logical- if functions can make assumptions such as pointerA != pointerB then that leads the way for avoiding aliasing restrictions.
As a side note, at least some users may consider this a useful feature: http://www.nntp.perl.org/group/perl.perl5.porters/2013/11/msg209482.html
The main problem with __assume is that it should never be used. Literally, if you have to use it, then the code it refers to should actually be commented out.