[GHC] #7450: Regression in optimisation time of functions with many patterns (6.12 to 7.4)?

[GHC]

#7450: Regression in optimisation time of functions with many patterns (6.12 to
7.4)?
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        Reporter:  iustin            |                   Owner:
            Type:  bug               |                  Status:  new
        Priority:  normal            |               Milestone:  7.12.1
       Component:  Compiler          |                 Version:  7.6.1
      Resolution:                    |                Keywords:
Operating System:  Unknown/Multiple  |            Architecture:
 Type of failure:  Compile-time      |  Unknown/Multiple
  performance bug                    |               Test Case:
      Blocked By:                    |                Blocking:
 Related Tickets:                    |  Differential Revisions:
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Comment (by bgamari):

 I've done some testing; notes can be found here.
 https://github.com/bgamari/ghc-T7450

 I have also attached a profile of GHC churning through a Read instance for
 a 1000-constructor ADT above.

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Ticket URL: <http://ghc.haskell.org/trac/ghc/ticket/7450#comment:10>
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