[GHC] #6166: Performance regression in mwc-random since 7.0.x

[GHC]

#6166: Performance regression in mwc-random since 7.0.x
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        Reporter:  bos               |                Owner:
            Type:  bug               |               Status:  new
        Priority:  high              |            Milestone:  8.0.1
       Component:  Compiler          |              Version:  7.4.2
      Resolution:                    |             Keywords:
Operating System:  Unknown/Multiple  |         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 Khudyakov):

 Does same regression present in latest version of mwc-random? AFAIR
 performance regression appears because GHC sometimes chose to inline
 lookup table in where block. It's marked as NOINLINE. It thus was
 recalculated on each call and caused slowdown. I moved it at top level and
 problem disapeared.

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Ticket URL: <http://ghc.haskell.org/trac/ghc/ticket/6166#comment:18>
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