[GHC] #9655: Do not UNPACK strict fields that are very wide

[GHC]

#9655: Do not UNPACK strict fields that are very wide
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              Reporter:  simonpj     |            Owner:
                  Type:  bug         |           Status:  new
              Priority:  normal      |        Milestone:
             Component:  Compiler    |          Version:  7.8.3
            Resolution:              |         Keywords:
      Operating System:              |     Architecture:  Unknown/Multiple
  Unknown/Multiple                   |       Difficulty:  Unknown
       Type of failure:              |       Blocked By:
  None/Unknown                       |  Related Tickets:
             Test Case:              |
              Blocking:              |
Differential Revisions:              |
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Comment (by jwlato):

 Ah, thanks for this ticket, I think it's a good idea.  Unfortunately my
 code isn't using `-funbox-strict-fields`.  To double-check I tried adding
 a `{-# NOUNPACK #-}` on the wide strict field and the behavior didn't
 change, so I think something else is going on with my code.  But I do
 think the suggested behavior is more sensible, I usually avoid `-funbox-
 strict-fields` because I don't want types like this auto-unboxed.

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Ticket URL: <http://ghc.haskell.org/trac/ghc/ticket/9655#comment:4>
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