[GHC] #8205: the 'impossible' happened : expectJust block_order

[GHC]

#8205: the 'impossible' happened : expectJust block_order
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        Reporter:  erikd                |            Owner:
            Type:  bug                  |           Status:  new
        Priority:  normal               |        Milestone:
       Component:  Compiler             |          Version:  7.7
      Resolution:                       |         Keywords:
Operating System:  Unknown/Multiple     |     Architecture:
 Type of failure:  Building GHC failed  |  Unknown/Multiple
       Test Case:                       |       Difficulty:  Unknown
        Blocking:                       |       Blocked By:
                                        |  Related Tickets:
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Changes (by jstolarek):

 * cc: jan.stolarek@… (added)


Comment:

 Austin sugests that this happened around the time when I pushed my
 loopification patch (this bug reported on 30 Aug, my patch pushed a day
 earlier). Panic happens in `splitAtProcPoints` function and I recall that
 my previous attempt at loopification as a Cmm pass didn't work with LLVM
 because it broke the invariant that a block may be reachable only from a
 single procpoint.

 So, can anyone experiencing this problem try
 {{{
 git revert d61c3ac186c94021c851f7a2a6d20631e35fc1ba
 }}}
 and see if this solves the problem?

-- 
Ticket URL: <http://ghc.haskell.org/trac/ghc/ticket/8205#comment:5>
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