[GHC] #1168: Optimisation sometimes decreases sharing in IO code

[GHC]

#1168: Optimisation sometimes decreases sharing in IO code
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              Reporter:  simonmar    |            Owner:
                  Type:  bug         |           Status:  new
              Priority:  normal      |        Milestone:  ⊥
             Component:  Compiler    |          Version:  6.6
            Resolution:              |         Keywords:
      Operating System:              |     Architecture:  Unknown/Multiple
  Unknown/Multiple                   |       Difficulty:  Unknown
       Type of failure:              |       Blocked By:
  None/Unknown                       |  Related Tickets:
             Test Case:              |
  nofib/spectral/calendar            |
              Blocking:              |
Differential Revisions:              |
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Comment (by simonpj):

 See #9349 for another example.

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Ticket URL: <http://ghc.haskell.org/trac/ghc/ticket/1168#comment:15>
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