[GHC] #7428: GHC compile times are seriously non-linear in program size

[GHC]

#7428: GHC compile times are seriously non-linear in program size
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        Reporter:  nudded            |                   Owner:
            Type:  bug               |                  Status:  new
        Priority:  normal            |               Milestone:  7.12.1
       Component:  Compiler          |                 Version:  7.4.2
      Resolution:                    |                Keywords:
Operating System:  Unknown/Multiple  |            Architecture:
 Type of failure:  Compile-time      |  Unknown/Multiple
  crash                              |               Test Case:
      Blocked By:                    |                Blocking:
 Related Tickets:                    |  Differential Revisions:
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Comment (by thoughtpolice):

 Here's a smaller version (that actually completes in a reasonable amount
 of time), along with a profile. Something is definitely quadratic or
 something around `CorePrep`/`TidyCore`; when run with `-v3`, I estimate
 `CorePrep` alone takes about 20 seconds.

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Ticket URL: <http://ghc.haskell.org/trac/ghc/ticket/7428#comment:17>
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