[GHC] #13563: Avoid redundant MOVes in generated code

[GHC]

#13563: Avoid redundant MOVes in generated code
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        Reporter:  alexbiehl         |                Owner:  (none)
            Type:  bug               |               Status:  new
        Priority:  normal            |            Milestone:
       Component:  Compiler          |              Version:  8.0.2
  (CodeGen)                          |
      Resolution:                    |             Keywords:
Operating System:  Windows           |         Architecture:  x86_64
                                     |  (amd64)
 Type of failure:  None/Unknown      |            Test Case:
      Blocked By:                    |             Blocking:
 Related Tickets:                    |  Differential Rev(s):
       Wiki Page:                    |
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Comment (by alexbiehl):

 I invoke ghc like this: `ghc line.hs -O -ddump-opt-cmm -fforce-recomp`

 ```
 $ ghc --version
 The Glorious Glasgow Haskell Compilation System, version 8.0.2
 ```

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Ticket URL: <http://ghc.haskell.org/trac/ghc/ticket/13563#comment:6>
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