[GHC] #11303: Pattern matching against sets of strings sharing a prefix blows up pattern checker

[GHC]

#11303: Pattern matching against sets of strings sharing a prefix blows up pattern
checker
-------------------------------------+-------------------------------------
        Reporter:  bgamari           |                Owner:
            Type:  bug               |               Status:  new
        Priority:  highest           |            Milestone:  8.0.1
       Component:  Compiler          |              Version:  7.11
      Resolution:                    |             Keywords:
Operating System:  Unknown/Multiple  |         Architecture:
 Type of failure:  Compile-time      |  Unknown/Multiple
  performance bug                    |            Test Case:  T11303
      Blocked By:                    |             Blocking:
 Related Tickets:  #11302            |  Differential Rev(s):  Phab:D1716,
       Wiki Page:                    |  Phab:D1719
-------------------------------------+-------------------------------------
Changes (by hvr):

 * owner:  gkaracha =>
 * status:  closed => new
 * resolution:  fixed =>


Comment:

 I just had matrix.h.h.o thrashing due to `text-icu` still requiring over
 10GiB with yesterdays GHC 8.0 snapshot :-(

 I tried compiling `text-icu-0.7.0.1:Data.Text.ICU.Regex.Internal` on my
 workstation (with swap-space disabled) takes over 30GiB, until the OOM
 killer finally kicks in:

 {{{
 [19687.231184] Out of memory: Kill process 18811 (ghc) score 929 or
 sacrifice child
 [19687.231186] Killed process 18811 (ghc) total-vm:1074146932kB, anon-
 rss:30410192kB, file-rss:0kB
 }}}

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Ticket URL: <http://ghc.haskell.org/trac/ghc/ticket/11303#comment:8>
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