[GHC] #14208: Performance with -O2 is worse than with -O0 which is worse than runghc

[GHC]

#14208: Performance with -O2 is worse than with -O0 which is worse than runghc
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        Reporter:  harendra          |                Owner:  (none)
            Type:  bug               |               Status:  new
        Priority:  normal            |            Milestone:
       Component:  Compiler          |              Version:  8.2.1
      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 mpickering):

 I can reproduce this. Thanks for the excellent test case.

 You can also build everything with `cabal new-build benchmarks`.

 Adding an `{- INLINABLE toList -}` improves the situation a lot but it is
 still slower than with -O0.

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Ticket URL: <http://ghc.haskell.org/trac/ghc/ticket/14208#comment:2>
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