[GHC] #11372: Loopification does not trigger for IO even if it could

[GHC]

#11372: Loopification does not trigger for IO even if it could
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        Reporter:  jscholl           |                Owner:
            Type:  bug               |               Status:  new
        Priority:  normal            |            Milestone:
       Component:  Compiler          |              Version:  7.10.3
  (CodeGen)                          |             Keywords:  cmm,
      Resolution:                    |  loopification, code generation
Operating System:  Unknown/Multiple  |         Architecture:
 Type of failure:  Runtime           |  Unknown/Multiple
  performance bug                    |            Test Case:
      Blocked By:                    |             Blocking:
 Related Tickets:                    |  Differential Rev(s):
       Wiki Page:                    |
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Changes (by jscholl):

 * Attachment "MapM.hs" added.

 mapM_ implementation as example of a loop which would benefit from the
 optimization, but currently doesn't.

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Ticket URL: <http://ghc.haskell.org/trac/ghc/ticket/11372>
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