[GHC] #8299: Add richer data model address arithmetic: AddrDiff and AddrInt (ie d Int_ptr_diff and Int_ptr_size)

[GHC]

#8299: Add richer data model address arithmetic: AddrDiff and AddrInt (ie d
Int_ptr_diff and Int_ptr_size)
----------------------------+----------------------------------------------
        Reporter:  carter   |            Owner:
            Type:  feature  |           Status:  new
  request                   |        Milestone:  7.10.1
        Priority:  high     |          Version:  7.6.3
       Component:           |         Keywords:
  Compiler                  |     Architecture:  Unknown/Multiple
      Resolution:           |       Difficulty:  Project (more than a week)
Operating System:           |       Blocked By:
  Unknown/Multiple          |  Related Tickets:
 Type of failure:           |
  None/Unknown              |
       Test Case:           |
        Blocking:  8287     |
----------------------------+----------------------------------------------

Comment (by simonpj):

 Presumably an `Addr#` is wide enough to contain an offset? So perhaps we
 should use `Addr#` instead of `Int#` for address differences?  We could
 have and `AddrDiff#` type, but then we'd need arithmetic over it etc.
 Maybe just a type synonym for `Addr#`?

 Anyway feel free to propose a concrete design.

 Simon

-- 
Ticket URL: <http://ghc.haskell.org/trac/ghc/ticket/8299#comment:3>
GHC <http://www.haskell.org/ghc/>
The Glasgow Haskell Compiler