[GHC] #6156: Optimiser bug on linux-powerpc

[GHC]

#6156: Optimiser bug on linux-powerpc
------------------------------------------+---------------------------------
  Reporter:  erikd                        |          Owner:  pcapriotti
      Type:  bug                          |         Status:  new       
  Priority:  normal                       |      Milestone:  7.6.1     
 Component:  Compiler                     |        Version:  7.4.1     
Resolution:                               |       Keywords:            
        Os:  Linux                        |   Architecture:  powerpc   
   Failure:  Incorrect result at runtime  |     Difficulty:  Unknown   
  Testcase:                               |      Blockedby:            
  Blocking:                               |        Related:            
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Comment(by erikd):

 Have some time to work on this again. The problem revolves around the
 following function:

 {{{
 word64ToWord32 :: Word64 -> Word32
 word64ToWord32 (W64# x) = W32# (word64ToWord# x)
 }}}

 where `word64ToWord#` is defined in `libraries/ghc-prim/GHC/IntWord64.hs`
 as:

 {{{
 foreign import ccall unsafe "hs_word64ToWord" word64ToWord# :: Word64# ->
 Word#
 }}}

 and `hs_word64ToWord` is defined `libraries/ghc-prim/cbits/longlong.c` as:

 {{{
 HsWord   hs_word64ToWord  (HsWord64 w) {return (HsWord)   w;}
 }}}

-- 
Ticket URL: <http://hackage.haskell.org/trac/ghc/ticket/6156#comment:26>
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