[GHC] #13564: Why does memory usage increase so much during CoreTidy?

[GHC]

#13564: Why does memory usage increase so much during CoreTidy?
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        Reporter:  rwbarton          |                Owner:  (none)
            Type:  task              |               Status:  new
        Priority:  normal            |            Milestone:  8.2.1
       Component:  Compiler          |              Version:  8.1
      Resolution:                    |             Keywords:
Operating System:  Unknown/Multiple  |         Architecture:
 Type of failure:  Compile-time      |  Unknown/Multiple
  performance bug                    |            Test Case:
      Blocked By:                    |             Blocking:
 Related Tickets:                    |  Differential Rev(s):  Phab:D3516
       Wiki Page:                    |
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Changes (by simonpj):

 * status:  closed => new
 * owner:  rwbarton => (none)
 * resolution:  fixed =>


Comment:

 > I found that this spike went away with -v, so I added a seqBinds which
 also eliminates the spike

 This is ok, but it's an un-satisfying Big Hammer. It forces us to make yet
 another pass over the entire program, when there is probably a more
 refined solution to hand.

 You might well be able to eliminate the other change in `tidyUnfolding`
 when you use the Big Hammer.  And maybe we should eliminate it, since we
 are now seq'ing the unfolding twice.

 But it would be nicer to find the source of the spike in the first place.

--
Ticket URL: <http://ghc.haskell.org/trac/ghc/ticket/13564#comment:7>
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