[GHC] #5810: OSX Lion building 7.4 head causes Haddock Divide By Zero

[GHC]

#5810: OSX Lion building 7.4 head causes Haddock Divide By Zero
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    Reporter:  codeweaver                             |       Owner:                     
        Type:  bug                                    |      Status:  new                
    Priority:  highest                                |   Milestone:  7.4.1              
   Component:  Compiler                               |     Version:  7.4.1-rc1          
    Keywords:  haddock divide by zero internal error  |          Os:  MacOS X            
Architecture:  Other                                  |     Failure:  Building GHC failed
  Difficulty:  Unknown                                |    Testcase:                     
   Blockedby:                                         |    Blocking:                     
     Related:                                         |  
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Comment(by Irene):

 This is a duplicate of a bug I reported and spent considerable effort
 diagnosing around October, but it was closed at that time as "cannot
 reproduce" although I don't think anyone followed the directions I gave
 properly.  I believe the long time before somebody else reported it means
 that, as I surmised, I was simply the only one attempting to build GHC on
 OS X Lion and that it has been broken all this time.  I can't find that
 bug in the system now, possibly due to my user-name change or something of
 that sort, so I'll summarize here.

 There are two underlying problems.  The more serious one is that cross-
 module inlining is only occurring when profiling is on, due to a change in
 where the function definitions are stored in the .hi files; as a result,
 rules that perform constant folding on arithmetic primops are not
 happening, so that a rational number is being constructed at runtime
 instead of compile-time.  The immediate cause of the divide-by-zero is
 that we are using a GMP function in an undocumented way (and always have
 been), so that it returns zero.  Even if one chooses to regard this as
 GMP's bug in an abstract philosophical sense ("the documentation ought to
 be clearer", perhaps), we're probably the only people hit by it, and it's
 breaking our build completely on OS X, so we kind of have to deal with it.

 I'll try again to dig up the original bug report when I get home from work
 tonight; it went into much more detail.

-- 
Ticket URL: <http://hackage.haskell.org/trac/ghc/ticket/5810#comment:9>
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