[GHC] #13518: CMM compiles with 8.0.2, fails with git HEAD

[GHC]

#13518: CMM compiles with 8.0.2, fails with git HEAD
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        Reporter:  erikd             |                Owner:  (none)
            Type:  bug               |               Status:  new
        Priority:  normal            |            Milestone:  8.4.1
       Component:  Compiler          |              Version:  8.1
      Resolution:                    |             Keywords:
Operating System:  Unknown/Multiple  |         Architecture:
 Type of failure:  Incorrect         |  Unknown/Multiple
  error/warning at compile-time      |            Test Case:
      Blocked By:                    |             Blocking:
 Related Tickets:                    |  Differential Rev(s):
       Wiki Page:                    |
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Comment (by slyfox):

 The snippet from #comment:5 compiles on:

 powerpc64le-unknown-linux-gnu-ghc-8.3.20170402
 changeset:852a43f360af09416d15777c8f10d704b5423a96

 m68k-unknown-linux-gnu-ghc-8.3.20170403
 changeset:1e58efb16f76b52c059d5e5d6c4c5d91c2abaad2

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Ticket URL: <http://ghc.haskell.org/trac/ghc/ticket/13518#comment:7>
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