[GHC] #7270: Incorrect optimization with Data.ByteString.append

[GHC]

#7270: Incorrect optimization with Data.ByteString.append
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 Reporter:  ocheron                      |          Owner:                   
     Type:  bug                          |         Status:  new              
 Priority:  normal                       |      Component:  libraries (other)
  Version:  7.6.1                        |       Keywords:                   
       Os:  Unknown/Multiple             |   Architecture:  Unknown/Multiple 
  Failure:  Incorrect result at runtime  |       Testcase:                   
Blockedby:                               |       Blocking:                   
  Related:                               |  
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Comment(by tab):

 I can also reproduce without append but using the shorter func:

 {{{
 func x = s `seq` r
   where
     r = B.map succ x
     s = B.map succ r
 }}}

 it fails at O and O2 on ghc 7.6.

-- 
Ticket URL: <http://hackage.haskell.org/trac/ghc/ticket/7270#comment:1>
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