[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
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        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:                    |
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Comment (by simonpj):

 Yes we expect to learn a lot.   From a scientific point of view (and
 writing the journal paper) I'm very interested to know how many of the
 single-entry thunks are found by the analysis.  Let's say there are N
 thunk allocation sites in the code.  We find that 15% are single-entry.
 If we found that only 20% were entered once (that 15% plus another 5%)
 that would mean there was at most another 5% that a more sophisticated
 analysis might find.   But the number might be much larger.

 If the number is large, we might start to characterise the missed
 opportunities further.  Perhaps some are being missed because of a bug in
 the analysis.  Others might be caught by a simple improvement in the
 analysis.

 That's the thinking.

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Ticket URL: <http://ghc.haskell.org/trac/ghc/ticket/10613#comment:11>
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