[GHC] #7580: Building PrimOps.cmm on OS X with LLVM 3.2 fails

[GHC]

#7580: Building PrimOps.cmm on OS X with LLVM 3.2 fails
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Reporter:  thoughtpolice        |          Owner:                  
    Type:  bug                  |         Status:  new             
Priority:  normal               |      Component:  Compiler (LLVM) 
 Version:  7.7                  |       Keywords:                  
      Os:  MacOS X              |   Architecture:  Unknown/Multiple
 Failure:  Building GHC failed  |      Blockedby:                  
Blocking:                       |        Related:  #7571, #7575    
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Comment(by thoughtpolice):

 There's logic to handle this in ```LlvmCodeGen.CodeGen``` but I'm not sure
 why it's not kicking in:


 {{{
         sameConv from ty reduce expand = do
             x'@(env', vx, stmts, top) <- exprToVar env x
             let sameConv' op = do
                 (v1, s1) <- doExpr ty $ Cast op vx ty
                 return (env', v1, stmts `snocOL` s1, top)
             let toWidth = llvmWidthInBits dflags ty
             -- LLVM doesn't like trying to convert to same width, so
             -- need to check for that as we do get Cmm code doing it.
             case widthInBits from  of
                  w | w < toWidth -> sameConv' expand
                  w | w > toWidth -> sameConv' reduce
                  _w              -> return x'
 }}}

-- 
Ticket URL: <http://hackage.haskell.org/trac/ghc/ticket/7580#comment:2>
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