[GHC] #8814: 7.8 optimizes attoparsec improperly

[GHC]

#8814: 7.8 optimizes attoparsec improperly
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        Reporter:  joelteon                 |            Owner:
            Type:  bug                      |           Status:  new
        Priority:  normal                   |        Milestone:
       Component:  Compiler                 |          Version:  7.8.1-rc1
      Resolution:                           |         Keywords:
Operating System:  MacOS X                  |     Architecture:  x86_64
 Type of failure:  Runtime performance bug  |  (amd64)
       Test Case:                           |       Difficulty:  Unknown
        Blocking:                           |       Blocked By:
                                            |  Related Tickets:
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Comment (by tibbe):

 Replying to [comment:6 joelteon]:
 > Using it when compiling the module above is enough.

 Could you dump the core and see if you can spot what difference the flag
 makes?

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Ticket URL: <http://ghc.haskell.org/trac/ghc/ticket/8814#comment:7>
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