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

[GHC]

#13331: Worker/wrapper can lead to sharing failure
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        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:                    |
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Comment (by simonpj):

 Can you make a repro case?

 What is this `ptrEq` thing?  It looks very smelly to me.  Surely at least
 it should be called `unsafePtrEq`.  What does it do?

 Reboxing in worker/wrapper is very difficult to avoid. It was described in
 our original strictness analysis paper, and also in the paper about
 constructor specialisation.

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Ticket URL: <http://ghc.haskell.org/trac/ghc/ticket/13331#comment:2>
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