#5539: GHC panic - Simplifier ticks exhausted
---------------------------------+------------------------------------------
Reporter: hvr | Owner:
Type: bug | Status: new
Priority: normal | Milestone:
Component: Compiler | Version: 7.3
Resolution: | Keywords:
Testcase: | Blockedby:
Difficulty: | Os: Linux
Blocking: | Architecture: x86_64 (amd64)
Failure: Compile-time crash |
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Comment(by carlhowells):
The statistics library is an additional case where this error pops up:
This is with -fsimpl-tick-factor=313
{{{
Preprocessing library statistics-0.9.0.0...
Building statistics-0.9.0.0...
[ 2 of 22] Compiling Statistics.Function ( Statistics/Function.hs,
dist/build/Statistics/Function.o )
ghc: panic! (the 'impossible' happened)
(GHC version 7.3.20111101 for x86_64-apple-darwin):
Simplifier ticks exhausted
When trying UnfoldingDone base:GHC.Base.plusInt{v rU} [gid]
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: 40738
}}}
At -fsimpl-tick-factor=314, I get this:
{{{
Preprocessing library statistics-0.9.0.0...
Building statistics-0.9.0.0...
[ 2 of 22] Compiling Statistics.Function ( Statistics/Function.hs,
dist/build/Statistics/Function.o )
WARNING: file compiler/simplCore/SimplCore.lhs line 578
Simplifier baling out after 4 iterations [494, 253, 20, 2] Size = 39959
Interesting! A join var that isn't let-no-escaped
[$j{v sbHe} [lid]]
}}}
In the same library, another module:
At -fsimpl-tick-factor=291, I get this:
{{{
Preprocessing library statistics-0.9.0.0...
Building statistics-0.9.0.0...
[ 8 of 22] Compiling Statistics.Quantile ( Statistics/Quantile.hs,
dist/build/Statistics/Quantile.o )
ghc: panic! (the 'impossible' happened)
(GHC version 7.3.20111101 for x86_64-apple-darwin):
Simplifier ticks exhausted
When trying UnfoldingDone ghc-prim:GHC.Classes.||{v rx} [gid]
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: 66349
}}}
At -fsimpl-tick-factor=292, I get this:
{{{
Building statistics-0.9.0.0...
[ 8 of 22] Compiling Statistics.Quantile ( Statistics/Quantile.hs,
dist/build/Statistics/Quantile.o )
WARNING: file compiler/simplCore/SimplCore.lhs line 578
Simplifier baling out after 4 iterations [66581, 5389, 242, 7] Size =
101356
WARNING: file compiler/simplCore/SetLevels.lhs line 1022
absVarsOf: discarding info on j_s8zy
WARNING: file compiler/simplCore/SetLevels.lhs line 1022
absVarsOf: discarding info on j_s8yO
}}}
--
Ticket URL: <http://hackage.haskell.org/trac/ghc/ticket/5539#comment:12>
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