[GHC] #9669: Long compile time/high memory usage for modules with many deriving clauses

[GHC]

#9669: Long compile time/high memory usage for modules with many deriving clauses
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              Reporter:  snoyberg    |            Owner:
                  Type:  bug         |           Status:  new
              Priority:  normal      |        Milestone:
             Component:  Compiler    |          Version:  7.8.3
            Resolution:              |         Keywords:
      Operating System:  Linux       |     Architecture:  x86_64 (amd64)
       Type of failure:  Compile-    |       Difficulty:  Unknown
  time performance bug               |       Blocked By:
             Test Case:              |  Related Tickets:
              Blocking:              |
Differential Revisions:              |
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Comment (by snoyberg):

 I've attached ghc.prof, which is a profile from compiling the Bar.hs
 module generated by the attached generate.hs. The hotspot appears to be
 the SimplTopBinds cost center, though my lack of experience with the GHC
 codebase prevents me from understanding what that means.

 If there are any other reports (e.g. heap profiles) that would be useful,
 let me know.

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Ticket URL: <http://ghc.haskell.org/trac/ghc/ticket/9669#comment:5>
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