[GHC] #915: Implement list fusion using streams instead of foldr/build

[GHC]

#915: Implement list fusion using streams instead of foldr/build
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    Reporter:  simonpj           |        Owner:                            
        Type:  task              |       Status:  new                       
    Priority:  low               |    Milestone:  7.0.2                     
   Component:  libraries/base    |      Version:  6.8                       
    Keywords:  fusion            |     Testcase:  N/A                       
   Blockedby:                    |   Difficulty:  Project (more than a week)
          Os:  Unknown/Multiple  |     Blocking:                            
Architecture:  Unknown/Multiple  |      Failure:  None/Unknown              
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Changes (by ezyang):

 * cc: ezyang@… (added)


Comment:

 For those playing along at home, more details on the inability to
 efficiently optimize concat/concatMap (more generally, fusion on nested
 lists) can be found in Section 7.2 of the
 [http://www.cse.unsw.edu.au/~dons/papers/CLS07.html "Stream Fusion"
 paper]. T'would probably be nice if the GHC optimizer experiments were
 public somewhere.

-- 
Ticket URL: <http://hackage.haskell.org/trac/ghc/ticket/915#comment:28>
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