Re: [GHC] #10083: ghc: panic! (the 'impossible' happened)

19 Feb 2015

      #10083: ghc: panic! (the 'impossible' happened)
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        Reporter:  hedayaty          |                   Owner:
            Type:  bug               |                  Status:  new
        Priority:  normal            |               Milestone:
       Component:  Compiler          |                 Version:  7.8.4
      Resolution:                    |                Keywords:
Operating System:  MacOS X           |            Architecture:  x86_64
 Type of failure:  Compile-time      |  (amd64)
  crash                              |               Test Case:
      Blocked By:                    |                Blocking:
 Related Tickets:                    |  Differential Revisions:
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Description changed by simonpj:

Old description:
...
I used hprotoc to generate some code for Google protocol buffers.
The QueryValue.proto file is attached.
You can install hprotoc tool using cabal.
then use
''hprotoc QueryValue.proto''
to generate code. Then create a minimal cabal file.
''cabal init -m --is-library -n''
Then if you build it with '''optimization enabled''', the build will fail
ghc: panic! (the 'impossible' happened)
  (GHC version 7.8.3 for x86_64-apple-darwin):
        Simplifier ticks exhausted
    When trying UnfoldingDone $j_sEMq{v} [lid]
    To increase the limit, use -fsimpl-tick-factor=N (default 100)
    If you need to do this, let GHC HQ know, and what factor you needed
    To see detailed counts use -ddump-simpl-stats
    Total ticks: 59242
New description:

 I used hprotoc to generate some code for Google protocol buffers.

 The QueryValue.proto file is attached.

 You can install `hprotoc` tool using cabal.
 then use
 {{{
 hprotoc QueryValue.proto
 }}}
 to generate code. Then create a minimal cabal file.
 {{{
 cabal init -m --is-library -n
 }}}
 Then if you build it with '''optimization enabled''', the build will fail
 {{{
 ghc: panic! (the 'impossible' happened)
   (GHC version 7.8.3 for x86_64-apple-darwin):
         Simplifier ticks exhausted
     When trying UnfoldingDone $j_sEMq{v} [lid]
     To increase the limit, use -fsimpl-tick-factor=N (default 100)
     If you need to do this, let GHC HQ know, and what factor you needed
     To see detailed counts use -ddump-simpl-stats
     Total ticks: 59242
 }}}

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Ticket URL: http://ghc.haskell.org/trac/ghc/ticket/10083#comment:5
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