[GHC] #15754: Move free variable computation to after STG passes

[GHC]

#15754: Move free variable computation to after STG passes
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        Reporter:  bgamari           |                Owner:  (none)
            Type:  bug               |               Status:  new
        Priority:  normal            |            Milestone:  8.8.1
       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:  #9718 #15867      |  Differential Rev(s):
       Wiki Page:                    |
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Changes (by sgraf):

 * related:  #9718 => #9718 #15867


Comment:

 #15867 has shown that there are at least `StgUnarise` and `StgCse` that
 are a little careless wrt. duplicates in the FV list. So removing the
 field altogether makes sense.

-- 
Ticket URL: <http://ghc.haskell.org/trac/ghc/ticket/15754#comment:9>
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