[GHC] #7411: Exceptions are optimized away in certain situations

[GHC]

#7411: Exceptions are optimized away in certain situations
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        Reporter:  SimonHengel       |                Owner:  (none)
            Type:  bug               |               Status:  new
        Priority:  high              |            Milestone:  8.6.1
       Component:  Compiler          |              Version:  7.6.1
      Resolution:                    |             Keywords:  seq, deepseq,
                                     |  evaluate, exceptions
Operating System:  Linux             |         Architecture:  x86_64
                                     |  (amd64)
 Type of failure:  Incorrect result  |            Test Case:
  at runtime                         |  simplCore/should_fail/T7411
      Blocked By:                    |             Blocking:
 Related Tickets:  #5129             |  Differential Rev(s):
       Wiki Page:                    |
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Comment (by tdammers):

 Compiling on GHC HEAD reproduces the problem:

 `../ghc/HEAD/_build/stage1/bin/ghc example.hs -fforce-recomp -O` produces
 a program that runs without error, while
 `../ghc/HEAD/_build/stage1/bin/ghc example.hs -fforce-recomp` behaves as
 it should.

 Comparing simplified Core shows that with `-O`, `deepseq` no longer
 appears in the output, so it seems that inlining `deepseq` is part of the
 problem.

-- 
Ticket URL: <http://ghc.haskell.org/trac/ghc/ticket/7411#comment:17>
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