[GHC] #14929: Program compiled with -O2 exhibits much worse performance

[GHC]

#14929: Program compiled with -O2 exhibits much worse performance
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        Reporter:  mpickering        |                Owner:  (none)
            Type:  bug               |               Status:  new
        Priority:  high              |            Milestone:
       Component:  Compiler          |              Version:  8.2.2
      Resolution:                    |             Keywords:
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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Comment (by George):

 According to
 https://www.reddit.com/r/haskell/comments/84qovv/an_example_of_code_where_ghcs_o2_makes_things/
 it's now down to 60 lines but I don't see any way to get those 60 lines:
 https://www.reddit.com/r/haskell/comments/84qovv/an_example_of_code_where_ghcs_o2_makes_things/dvshdb8

 Also according to that page, compiling with -fno-full-laziness is a
 workaround

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Ticket URL: <http://ghc.haskell.org/trac/ghc/ticket/14929#comment:2>
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