[GHC] #12790: GHC 8.0.1 uses copious amounts of RAM and time when trying to compile lambdabot-haskell-plugins

[GHC]

#12790: GHC 8.0.1 uses copious amounts of RAM and time when trying to compile
lambdabot-haskell-plugins
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        Reporter:  clint             |                Owner:
            Type:  bug               |               Status:  new
        Priority:  normal            |            Milestone:
       Component:  Compiler          |              Version:  8.0.1
      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):

 To elaborate on the observation that enabling `-fprof-auto` fixes the
 slowdown, it's because if you add an `SCC` pragma for `list`:

 {{{#!hs
 {-# SCC list #-}
 list :: Parser Expr
 list = ...
 }}}

 Then it also fixes the slowdown. (`-fprof-auto` was just doing this under
 the hood).

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Ticket URL: <http://ghc.haskell.org/trac/ghc/ticket/12790#comment:15>
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