[GHC] #10549: floatExpr tick break<2>

[GHC]

#10549: floatExpr tick break<2>
-------------------------------------+-------------------------------------
        Reporter:  NeilMitchell      |                   Owner:  bgamari
            Type:  bug               |                  Status:  closed
        Priority:  high              |               Milestone:  7.10.3
       Component:  Compiler          |                 Version:  7.10.2
      Resolution:  fixed             |                Keywords:
Operating System:  Unknown/Multiple  |            Architecture:
                                     |  Unknown/Multiple
 Type of failure:  None/Unknown      |               Test Case:  T10549
      Blocked By:                    |                Blocking:
 Related Tickets:                    |  Differential Revisions:  Phab:D1128
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Comment (by NeilMitchell):

 I ran into this again and reduced it to something fairly different, and
 quite a lot simpler. You may want to incorporate the new example as an
 additional test case:

 {{{
 {-# OPTIONS_GHC -O #-}
 module Main(main) where
 import GHC.Exts
 main = print 1
 go (Ptr a) = a
 }}}

 Note the revised test case only requires GHC, not ByteString etc.
 With GHC 7.10.2, running runhaskell over it gives:

 {{{
 ghc: panic! (the 'impossible' happened)
   (GHC version 7.10.2 for i386-unknown-mingw32):
         floatExpr tick break<1>()
 }}}

--
Ticket URL: <http://ghc.haskell.org/trac/ghc/ticket/10549#comment:16>
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