[GHC] #7574: Register allocator chokes on certain branches with literals

[GHC]

#7574: Register allocator chokes on certain branches with literals
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        Reporter:  thoughtpolice     |            Owner:  simonmar
            Type:  bug               |           Status:  new
        Priority:  highest           |        Milestone:  7.8.1
       Component:  Compiler (NCG)    |          Version:  7.7
      Resolution:                    |         Keywords:  ncg, codegen
Operating System:  Unknown/Multiple  |     Architecture:  Unknown/Multiple
 Type of failure:  Compile-time      |       Difficulty:  Unknown
  crash                              |       Blocked By:  7573
       Test Case:                    |  Related Tickets:  #7571,#7534,
  codeGen/should_compile/T7574       |  #7814
        Blocking:                    |
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Comment (by thoughtpolice):

 Thank you Simon. I'm quite busy at the moment - and I've also had a
 partially working patch (probably similar to yours,) but mine also threw
 away too much code when discarding unreachable blocks. I mean to brain-
 dump it to you, but I imagine you can manage :)

-- 
Ticket URL: <http://ghc.haskell.org/trac/ghc/ticket/7574#comment:25>
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