[GHC] #13331: Worker/wrapper can lead to sharing failure

[GHC]

#13331: Worker/wrapper can lead to sharing failure
-------------------------------------+-------------------------------------
        Reporter:  dfeuer            |                Owner:  (none)
            Type:  bug               |               Status:  new
        Priority:  normal            |            Milestone:  8.4.1
       Component:  Compiler          |              Version:  8.1
      Resolution:                    |             Keywords:
Operating System:  Unknown/Multiple  |         Architecture:
 Type of failure:  Runtime           |  Unknown/Multiple
  performance bug                    |            Test Case:
      Blocked By:                    |             Blocking:
 Related Tickets:                    |  Differential Rev(s):
       Wiki Page:                    |
-------------------------------------+-------------------------------------

Comment (by dfeuer):

 Ah, I see better now. My tiny list example can probably be fixed
 relatively easily using a "just pass both" approach, but my real-life
 example involves some knowledge the compiler doesn't have: that we tend to
 have the box already and/or we end up needing the box, and that the cost
 of losing sharing here is higher than it may look. That application
 dependence seems to argue in favor of a pragma-based solution.

--
Ticket URL: <http://ghc.haskell.org/trac/ghc/ticket/13331#comment:7>
GHC <http://www.haskell.org/ghc/>
The Glasgow Haskell Compiler