[GHC] #13916: Optimizations create run time seg faults

[GHC]

#13916: Optimizations create run time seg faults
-------------------------------------+-------------------------------------
        Reporter:  newthin           |                Owner:  (none)
            Type:  bug               |               Status:  new
        Priority:  highest           |            Milestone:  8.2.2
       Component:  Compiler          |              Version:  8.0.2
  (CodeGen)                          |
      Resolution:                    |             Keywords:  optimization
Operating System:  Unknown/Multiple  |         Architecture:
                                     |  Unknown/Multiple
 Type of failure:  Runtime crash     |            Test Case:
      Blocked By:                    |             Blocking:
 Related Tickets:                    |  Differential Rev(s):
       Wiki Page:                    |
-------------------------------------+-------------------------------------

Comment (by bgamari):

 For the record, I now have a
 [[https://github.com/bgamari/T13916-repro/commit/508c8050f09a6f8a44b0aa526fb06b55a3cfd8d4|simplification]]
 of the testcase that produces an "MVar object entered!" assertion instead
 of a segmentation fault.

-- 
Ticket URL: <http://ghc.haskell.org/trac/ghc/ticket/13916#comment:14>
GHC <http://www.haskell.org/ghc/>
The Glasgow Haskell Compiler