[GHC] #8275: Loopification breaks profiling

[GHC]

#8275: Loopification breaks profiling
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        Reporter:  jstolarek            |            Owner:
            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:
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Changes (by jstolarek):

 * owner:  jstolarek =>


Comment:

 OK, I know what preemption is. There are three steps that need to be done:

   1) Fix generation of stack checks, i.e. fix correctness (this should be
 simple, I know how to do this).

   2) Make sure that stack check doesn't get duplicated, i.e. fix
 performance

   3) Make sure that loopification jumps before LDV code and hope that this
 solves the problem.

 There is one thing that worries me. We want the loop to begin after the
 stack check but before the heap check. Now if LDV code is placed before
 the stack check then of course this requirement cannot be fulfilled. I'm
 not sure how to handle such situation.

 Anyway, I'm leaving MSR today and my work on this ticket will be put on
 hold for a couple of weeks. If anyone wants to take over feel free. I'm
 unassigning myself for the time being.

-- 
Ticket URL: <http://ghc.haskell.org/trac/ghc/ticket/8275#comment:14>
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