[GHC] #16197: Strictness is not preserved under -O1

[GHC]

#16197: Strictness is not preserved under -O1
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        Reporter:  alang9            |                Owner:  (none)
            Type:  bug               |               Status:  new
        Priority:  normal            |            Milestone:
       Component:  Compiler          |              Version:  8.4.1
      Resolution:                    |             Keywords:
Operating System:  Unknown/Multiple  |         Architecture:
 Type of failure:  Incorrect result  |  Unknown/Multiple
  at runtime                         |            Test Case:
      Blocked By:                    |             Blocking:
 Related Tickets:                    |  Differential Rev(s):
       Wiki Page:                    |
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Comment (by alang9):

 The bug still appears with `-O1 -fno-enable-rewrite-rules`. The following
 BUILTIN rules still fire:

 {{{
 Rule fired: Class op null (BUILTIN)
 Rule fired: Class op foldl' (BUILTIN)
 Rule fired: Class op null (BUILTIN)
 Rule fired: Class op foldl' (BUILTIN)
 Rule fired: Class op >>= (BUILTIN)
 Rule fired: Class op return (BUILTIN)
 Rule fired: Class op return (BUILTIN)
 Rule fired: Class op enumFromTo (BUILTIN)
 Rule fired: Class op foldl' (BUILTIN)
 Rule fired: Class op fromInteger (BUILTIN)
 Rule fired: integerToInt (BUILTIN)
 Rule fired: Class op show (BUILTIN)
 Rule fired: Class op show (BUILTIN)
 Rule fired: Class op return (BUILTIN)
 Rule fired: Class op showsPrec (BUILTIN)
 Rule fired: Class op showsPrec (BUILTIN)
 Rule fired: Class op showsPrec (BUILTIN)
 Rule fired: Class op showsPrec (BUILTIN)
 Rule fired: ># (BUILTIN)
 Rule fired: ==# (BUILTIN)
 }}}

-- 
Ticket URL: <http://ghc.haskell.org/trac/ghc/ticket/16197#comment:3>
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