[GHC] #11095: -O0 -g slows GHC down on list literals (compared to -O0 without -g)

[GHC]

#11095: -O0 -g slows GHC down on list literals (compared to -O0 without -g)
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        Reporter:  slyfox            |                Owner:
            Type:  bug               |               Status:  new
        Priority:  normal            |            Milestone:
       Component:  Compiler          |              Version:  7.10.2
      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):  phab:D3001
       Wiki Page:                    |
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Comment (by dfeuer):

 Unfortunately, part of niteria's change was semantically invalid and
 needed to be reverted. I'm trying to understand a little more of what's
 going on around it that makes it a hot spot. niteria's observation that we
 almost always reach the `otherwise` suggests that perhaps we can find a
 quicker way to get there (rather than checking if each contains the other
 immediately, first find a way to discover or approximate that they
 certainly don't). But working out the asymptotic problems will surely be
 more important than that. Right now I'm struggling a bit to understand
 what `mkTick` is doing and how.

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Ticket URL: <http://ghc.haskell.org/trac/ghc/ticket/11095#comment:9>
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