[GHC] #11555: catch _|_ breaks at -O1

[GHC]

#11555: catch _|_ breaks at -O1
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        Reporter:  slyfox            |                Owner:
            Type:  bug               |               Status:  patch
        Priority:  highest           |            Milestone:  8.0.1
       Component:  Compiler          |              Version:  8.0.1-rc2
      Resolution:                    |             Keywords:
Operating System:  Unknown/Multiple  |         Architecture:
 Type of failure:  Incorrect result  |  Unknown/Multiple
  at runtime                         |            Test Case:
      Blocked By:                    |             Blocking:
 Related Tickets:                    |  Differential Rev(s):  Phab:D1973
       Wiki Page:                    |
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Comment (by simonpj):

 OK, so pls merge the patch in comnent:17.  And could you please add Neil's
 test in comment:14 as a regression test?

 Neil: I think this should work for you now.

 Thanks

 Simon

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Ticket URL: <http://ghc.haskell.org/trac/ghc/ticket/11555#comment:18>
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