[GHC] #10613: Mechanism for checking that we only enter single-entry thunks once

[GHC]

#10613: Mechanism for checking that we only enter single-entry thunks once
-------------------------------------+-------------------------------------
        Reporter:  bgamari           |                Owner:
            Type:  feature request   |               Status:  new
        Priority:  normal            |            Milestone:
       Component:  Compiler          |              Version:  7.10.1
      Resolution:                    |             Keywords:
Operating System:  Unknown/Multiple  |         Architecture:
                                     |  Unknown/Multiple
 Type of failure:  Other             |            Test Case:
      Blocked By:                    |             Blocking:
 Related Tickets:                    |  Differential Rev(s):
       Wiki Page:                    |
-------------------------------------+-------------------------------------

Comment (by nomeata):

 Ok, I implemented it, and nofib still runs (yay). The code is yet
 unrepresentable, though :-)

 Preliminary observations (gotta run now):

 In all of nofib, there is one single entry thunk that is entered multiple
 times (something in `gamteb`, allocated 2048 times, each time with two
 entries). Did not investigate yet, though.

 On first glance, plenty of thunks which appear to be single-entry, but are
 not marked as such.

--
Ticket URL: <http://ghc.haskell.org/trac/ghc/ticket/10613#comment:20>
GHC <http://www.haskell.org/ghc/>
The Glasgow Haskell Compiler