[GHC] #9132: takeWhile&C. still not fusible

[GHC]

#9132: takeWhile&C. still not fusible
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        Reporter:  Blaisorblade      |            Owner:  skeuchel
            Type:  bug               |           Status:  new
        Priority:  normal            |        Milestone:
       Component:  libraries/base    |          Version:  7.8.2
      Resolution:                    |         Keywords:  fusion
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):

 Great analysis.

 I think the change can go in nevertheless. Optimization is hardly ever a
 win in all cases, and I think the regression is just a random knock-on-
 effect that could well have been an improvement. Also, it is not takeWhile
 specific, but rather a problem with the list-fusion setup in general.

 I’d say we can merge this.

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Ticket URL: <http://ghc.haskell.org/trac/ghc/ticket/9132#comment:13>
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