[GHC] #11795: Performance issues with replicateM_

[GHC]

#11795: Performance issues with replicateM_
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        Reporter:  snoyberg          |                Owner:  snoyberg
            Type:  bug               |               Status:  new
        Priority:  normal            |            Milestone:
       Component:  libraries/base    |              Version:  7.10.3
      Resolution:                    |             Keywords:
Operating System:  MacOS X           |         Architecture:  x86_64
 Type of failure:  Runtime           |  (amd64)
  performance bug                    |            Test Case:
      Blocked By:                    |             Blocking:
 Related Tickets:                    |  Differential Rev(s):
       Wiki Page:                    |
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Comment (by snoyberg):

 Actually, it would appear that Ben already modified the implementation of
 `replicateM_` to something different than I saw:

 {{{#!hs
 replicateM_ 0 _   = pure ()
 replicateM_ n x   = x *> replicateM_ (pred n) x
 }}}

 The implementation I've given here still seems to perform better, due to
 usage of the worker/wrapper transform. It also keeps the semantics of the
 current version in GHC 7.10.3 for negative values.

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Ticket URL: <http://ghc.haskell.org/trac/ghc/ticket/11795#comment:4>
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