[GHC] #7571: LLVM codegen does not handle integer literals in branch conditionals.

[GHC]

#7571: LLVM codegen does not handle integer literals in branch conditionals.
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    Reporter:  thoughtpolice     |       Owner:  thoughtpolice     
        Type:  bug               |      Status:  patch             
    Priority:  normal            |   Milestone:                    
   Component:  Compiler (LLVM)   |     Version:  7.7               
    Keywords:  llvm, codegen     |          Os:  Unknown/Multiple  
Architecture:  Unknown/Multiple  |     Failure:  Compile-time crash
  Difficulty:  Unknown           |    Testcase:                    
   Blockedby:  7573              |    Blocking:                    
     Related:  #7574, #7575      |  
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Changes (by simonmar):

  * difficulty:  => Unknown


Comment:

 Ok by me.  I think we should clarify that `CmmCondBranch` can have an
 arbitrary expression as the conditional, and it should be a word-sized
 integral with non-zero meaning true.

 The alternative is to declare that the argument to `CmmCondBranch` must be
 a conditional, but I think that would be worse: we wouldn't be able to
 unconditionally rewrite "1 == 2" to zero everywhere, we would probably
 need dummy "ALWAYS" and "NEVER" conditionals.

-- 
Ticket URL: <http://hackage.haskell.org/trac/ghc/ticket/7571#comment:12>
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