[GHC] #11597: Optimize cmpTypeX

[GHC]

#11597: Optimize cmpTypeX
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        Reporter:  goldfire          |                Owner:  goldfire
            Type:  task              |               Status:  new
        Priority:  highest           |            Milestone:  8.0.1
       Component:  Compiler          |              Version:  7.10.3
      Resolution:                    |             Keywords:
Operating System:  Unknown/Multiple  |         Architecture:
                                     |  Unknown/Multiple
 Type of failure:  None/Unknown      |            Test Case:
      Blocked By:                    |             Blocking:
 Related Tickets:                    |  Differential Rev(s):
       Wiki Page:                    |
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Comment (by simonpj):

 Also see Bartosz's data in #11371, comment 43. Data here:
 {{{
  346492   piResultTys Levity -> *
  308771   piResultTys * -> * -> *
  147177   piResultTys * -> *
   18410   piResultTys * -> * -> * -> *
   10407   piResultTys *
     142   piResultTys * -> #
      70   piResultTys Levity
      66   piResultTys * -> Constraint
      24   piResultTys (* -> *) -> Constraint
 }}}
 (Relevance: `piResultTys` is called by `typeKind`, which is called by
 `cmpTypeX`.)

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Ticket URL: <http://ghc.haskell.org/trac/ghc/ticket/11597#comment:1>
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