[GHC] #9356: scanl does not participate in stream fusion

[GHC]

#9356: scanl does not participate in stream fusion
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              Reporter:  dfeuer      |            Owner:
                  Type:  bug         |           Status:  patch
              Priority:  normal      |        Milestone:
             Component:  Compiler    |          Version:  7.8.3
            Resolution:              |         Keywords:
      Operating System:              |     Architecture:  Unknown/Multiple
  Unknown/Multiple                   |       Difficulty:  Unknown
       Type of failure:  Runtime     |       Blocked By:
  performance bug                    |  Related Tickets:
             Test Case:              |
              Blocking:              |
Differential Revisions:              |
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Comment (by dfeuer):

 It looks like strictness analysis can work its magic in nice cases and
 unbox the accumulator, erasing the let. I think this is probably good to
 go.

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Ticket URL: <http://ghc.haskell.org/trac/ghc/ticket/9356#comment:3>
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