[GHC] #15304: Huge increase of compile time and memory use from 8.0.2 to 8.2.2 or 8.4.2

[GHC]

#15304: Huge increase of compile time and memory use from 8.0.2 to 8.2.2 or 8.4.2
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        Reporter:  NathanWaivio      |                Owner:  tdammers
            Type:  bug               |               Status:  new
        Priority:  high              |            Milestone:  8.6.1
       Component:  Compiler          |              Version:  8.4.2
      Resolution:                    |             Keywords:
Operating System:  Unknown/Multiple  |         Architecture:  x86_64
 Type of failure:  Compile-time      |  (amd64)
  performance bug                    |            Test Case:
      Blocked By:                    |             Blocking:
 Related Tickets:                    |  Differential Rev(s):
       Wiki Page:                    |
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Comment (by tdammers):

 Sounds like a promising lead, if not the key to figuring this out.
 Worker/wrapper is generally a good thing to do; in theory, all it should
 do is turn arguments to recursive function calls closures, thus reducing
 the argument-passing overhead. But I can imagine that this would also get
 in the way of inlinings and `RULES`.

 So what we're looking for is code that follows the pattern that makes it a
 candidate for worker/wrapper optimization (parameters passed through
 recursive calls unchanged), such that the worker/wrapper optimization
 breaks up expressions that might otherwise trigger useful inlinings or
 rewrites.

-- 
Ticket URL: <http://ghc.haskell.org/trac/ghc/ticket/15304#comment:17>
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