[GHC] #9961: compile-time performance regression compiling genprimcode

[GHC]

#9961: compile-time performance regression compiling genprimcode
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        Reporter:  hvr               |                   Owner:  simonpj
            Type:  bug               |                  Status:  new
        Priority:  highest           |               Milestone:  7.10.1
       Component:  Compiler          |                 Version:  7.10.1-rc1
      Resolution:                    |                Keywords:
Operating System:  Unknown/Multiple  |            Architecture:
 Type of failure:  Compile-time      |  Unknown/Multiple
  performance bug                    |               Test Case:
      Blocked By:                    |                Blocking:
 Related Tickets:                    |  Differential Revisions:
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Comment (by scpmw):

 Turns out that this might have been my fault anyway. Background here is
 that CSE needs to strip ticks from expressions fairly often, and
 `stripTicks` was not particularly efficient at it.

 The attached patch should restore acceptable performance. I also added a
 performance test - this is fairly easy to reproduce.

 (For the cost-centre issue mentioned above, see Phabricator D616).

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Ticket URL: <http://ghc.haskell.org/trac/ghc/ticket/9961#comment:14>
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