[GHC] #12990: Partially applied constructors with unpacked fields simplified badly

[GHC]

#12990: Partially applied constructors with unpacked fields simplified badly
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        Reporter:  dfeuer            |                Owner:
            Type:  bug               |               Status:  new
        Priority:  normal            |            Milestone:
       Component:  Compiler          |              Version:  8.0.1
      Resolution:                    |             Keywords:
Operating System:  Unknown/Multiple  |         Architecture:
 Type of failure:  Runtime           |  Unknown/Multiple
  performance bug                    |            Test Case:
      Blocked By:                    |             Blocking:
 Related Tickets:                    |  Differential Rev(s):
       Wiki Page:                    |
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Comment (by simonpj):

 In `MkId` line 511 we have
 {{{
              wrap_unf = mkInlineUnfolding (Just wrap_arity) wrap_rhs
 }}}
 The `Just wrap_arity` is what prevents GHC inlining the wrapper until it
 is saturated.  Change it to `Nothing` to allow a partially-applied wrapper
 to inline.

 Worth a try.  I doubt it'd have any bad effects.

--
Ticket URL: <http://ghc.haskell.org/trac/ghc/ticket/12990#comment:3>
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