[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:                    
        Type:  bug               |      Status:  new               
    Priority:  normal            |   Milestone:                    
   Component:  Compiler (NCG)    |     Version:  7.7               
    Keywords:  ncg, codegen      |          Os:  Unknown/Multiple  
Architecture:  Unknown/Multiple  |     Failure:  Compile-time crash
  Difficulty:  Unknown           |    Testcase:                    
   Blockedby:  7573              |    Blocking:                    
     Related:  #7571,#7534       |  
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Changes (by Feuerbach):

 * cc: roma@… (added)


Comment:

 This bug also affects the "statistics" library. To reproduce, try to
 install statistics-0.10.2.0 from hackage with profiling enabled using GHC
 HEAD. It fails with a similar message

 {{{
 [ 4 of 39] Compiling Statistics.Transform ( Statistics/Transform.hs,
 dist/build/Statistics/Transform.p_o )
 ghc-stage2: panic! (the 'impossible' happened)
   (GHC version 7.7.20130407 for i386-unknown-linux):
         allocateRegsAndSpill: Cannot read from uninitialized register
     %vI_cdUj
 }}}

-- 
Ticket URL: <http://hackage.haskell.org/trac/ghc/ticket/7574#comment:9>
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