[GHC] #15698: SingleEntry update flag for Stg bindings is not used

[GHC]

#15698: SingleEntry update flag for Stg bindings is not used
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        Reporter:  osa1              |                Owner:  (none)
            Type:  task              |               Status:  new
        Priority:  lowest            |            Milestone:  8.6.1
       Component:  Compiler          |              Version:  8.6.1
      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):

 > it seems like for a thunk (a binding with no arguments) we generate a
 thunk header and push an update frame regardless of the update flag

 I don't think so. See
 {{{
 setupUpdate closure_info node body
   | not (lfUpdatable (closureLFInfo closure_info))
   = body
 }}}
 That is, it's a no-op if the thunk is non-updatable (single-entry).

-- 
Ticket URL: <http://ghc.haskell.org/trac/ghc/ticket/15698#comment:1>
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