[GHC] #14626: No need to enter a scrutinised value

[GHC]

#14626: No need to enter a scrutinised value
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        Reporter:  heisenbug         |                Owner:  heisenbug
            Type:  bug               |               Status:  new
        Priority:  normal            |            Milestone:
       Component:  Compiler          |              Version:  8.2.2
      Resolution:                    |             Keywords:  performance
Operating System:  Unknown/Multiple  |         Architecture:
                                     |  Unknown/Multiple
 Type of failure:  None/Unknown      |            Test Case:
      Blocked By:                    |             Blocking:
 Related Tickets:  #13861            |  Differential Rev(s):
       Wiki Page:                    |
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Changes (by heisenbug):

 * owner:  (none) => heisenbug


Comment:

 @spj Yes the perf changes will be small, but I hope to get more by the
 time #13861 is ready. Anyway this will result in better (less branchy)
 code, so I think it is worth it.

 Thanks for the `isEvaldUnfolding` hint! I ''knew'' there must be a correct
 way to do it. I'll test, and come back with a phabricator.

-- 
Ticket URL: <http://ghc.haskell.org/trac/ghc/ticket/14626#comment:1>
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