[GHC] #15703: Significant compilation time blowup when refactoring singletons-heavy code

[GHC]

#15703: Significant compilation time blowup when refactoring singletons-heavy code
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        Reporter:  RyanGlScott       |                Owner:  (none)
            Type:  bug               |               Status:  new
        Priority:  normal            |            Milestone:  8.8.1
       Component:  Compiler          |              Version:  8.6.1
      Resolution:                    |             Keywords:
Operating System:  Unknown/Multiple  |         Architecture:
 Type of failure:  Compile-time      |  Unknown/Multiple
  performance bug                    |            Test Case:
      Blocked By:                    |             Blocking:
 Related Tickets:                    |  Differential Rev(s):
       Wiki Page:                    |
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Comment (by RyanGlScott):

 If you're wondering why I split the code up into two separate modules
 (instead of combining it into a single module), I observed that combining
 things into a single module actually made the compilation slowdown less
 severe (it took about 1 minute to compile, as opposed to the ~3m30s
 compile time shown above). I suspect that dividing up the code into
 further modules might exacerbate the compile times even more, since in the
 original project that I took this code from, it actually takes //longer//
 than 3m30s to compile the whole thing with `-O1`.

-- 
Ticket URL: <http://ghc.haskell.org/trac/ghc/ticket/15703#comment:1>
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