[GHC] #1600: Optimisation: CPR the results of IO

[GHC]

#1600: Optimisation: CPR the results of IO
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        Reporter:  simonmar          |            Owner:
            Type:  task              |           Status:  new
        Priority:  lowest            |        Milestone:  7.6.2
       Component:  Compiler          |          Version:  6.6.1
      Resolution:                    |         Keywords:
Operating System:  Unknown/Multiple  |     Architecture:  Unknown/Multiple
 Type of failure:  Runtime           |       Difficulty:  Moderate (less
  performance bug                    |  than a day)
       Test Case:                    |       Blocked By:
        Blocking:                    |  Related Tickets:
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Comment (by nomeata):

 Replying to [comment:22 simonpj]:
 > A neat approach might be to say that, when doing the fixpoint on a
 recursive group, trim off any nested CPR info from the demand signatures
 we use when processing the RHSs.

 Woudn’t that be far too imprecise? That would completely prevent nested
 CPR in loops, like `factIO` above...

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Ticket URL: <http://ghc.haskell.org/trac/ghc/ticket/1600#comment:23>
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