[GHC] #14378: Unreasonably high memory use when compiling with profiling and -O2/-O2

[GHC]

#14378: Unreasonably high memory use when compiling with profiling and -O2/-O2
-------------------------------------+-------------------------------------
           Reporter:  AndreasK       |             Owner:  (none)
               Type:  bug            |            Status:  new
           Priority:  normal         |         Milestone:
          Component:  Compiler       |           Version:  8.2.1
           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):                 |         Wiki Page:
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 Based on [https://github.com/Daniel-Diaz/matrix/issues/43] I tried that
 myself.

 * Without profiling: <10 sec, <110M Residency
 * Profiling and -O: 90sec, 1.5GB Residency
 * Profiling and -O2: Killed it after 4 Minutes and it started swapping on
 a 16GB Ram machine.

 The invocation was: ghc Matrix.hs -prof -fprof-auto  -c -fforce-recomp -O
 -v -fprof-auto-exported -caf-all -auto-all -fstatic-argument-
 transformation

 Numbers above from 8.0.2.

 8.2.1 improved to slightly worse than -O1 with ~95 sec and ~2.5GB ram
 usage. Still seems like a bug though.

 I haven't tried HEAD yet.

-- 
Ticket URL: <http://ghc.haskell.org/trac/ghc/ticket/14378>
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