[GHC] #8275: Loopification breaks profiling

[GHC]

#8275: Loopification breaks profiling
----------------------------------------+----------------------------------
        Reporter:  jstolarek            |            Owner:  jstolarek
            Type:  bug                  |           Status:  new
        Priority:  highest              |        Milestone:
       Component:  Profiling            |          Version:  7.7
      Resolution:                       |         Keywords:
Operating System:  Unknown/Multiple     |     Architecture:
 Type of failure:  Building GHC failed  |  Unknown/Multiple
       Test Case:                       |       Difficulty:  Unknown
        Blocking:  8298                 |       Blocked By:
                                        |  Related Tickets:
----------------------------------------+----------------------------------

Comment (by jstolarek):

 Another thing I observed is that my example is very sensitive. If you
 modify it by removing any call to `f` (for example by changing scrutinee
 to `case n of...` or second branch to `5 -> 5`) or replace second pattern
 match in case alternatives with `_` (i.e second branch becomes `_ -> f (n
 - 1)`) the segfault disappears. I haven't yet examined the differences in
 Cmm between these versions, but if the problem is caused by code generated
 for `f` this should allow us to track the cause. I don't know yet how to
 debug this issue if the problem is hidden in the libraries :-/

-- 
Ticket URL: <http://ghc.haskell.org/trac/ghc/ticket/8275#comment:7>
GHC <http://www.haskell.org/ghc/>
The Glasgow Haskell Compiler