[GHC] #13536: Program which terminates instantly in GHC 8.0.2 runs for minutes with 8.2.1

[GHC]

#13536: Program which terminates instantly in GHC 8.0.2 runs for minutes with 8.2.1
-------------------------------------+-------------------------------------
        Reporter:  RyanGlScott       |                Owner:  (none)
            Type:  bug               |               Status:  merge
        Priority:  highest           |            Milestone:  8.2.1
       Component:  Compiler          |              Version:  8.1
      Resolution:  fixed             |             Keywords:
Operating System:  Unknown/Multiple  |         Architecture:
 Type of failure:  Runtime           |  Unknown/Multiple
  performance bug                    |            Test Case:  T13536
      Blocked By:                    |             Blocking:
 Related Tickets:                    |  Differential Rev(s):  Phab:D3437
       Wiki Page:                    |
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Changes (by nomeata):

 * testcase:   => T13536


Comment:

 >  So please let's add it as a regression test! (To HEAD at least.)
 Thanks.

 How do we robustly test whether a program is “fast”? I already did add a
 regression test that checks for the particular problem much more
 targetedly.

--
Ticket URL: <http://ghc.haskell.org/trac/ghc/ticket/13536#comment:26>
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