#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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Changes (by carlhowells):
* cc: chowells79@… (added)
Comment:
Posting again because of how crazy this first case is...
In criterion:
At -fsimpl-tick-factor=614, I get this:
{{{
Building criterion-0.5.1.0...
[ 9 of 12] Compiling Criterion.Analysis ( Criterion/Analysis.hs,
dist/build/Criterion/Analysis.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.$fMonadIO_$c>>={v rvx} [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: 203602
}}}
At -fsimpl-tick-factor=615, I get this:
{{{
Building criterion-0.5.1.0...
[ 9 of 12] Compiling Criterion.Analysis ( Criterion/Analysis.hs,
dist/build/Criterion/Analysis.o )
WARNING: file compiler/simplCore/SimplCore.lhs line 578
Simplifier baling out after 4 iterations [203871, 45952, 981, 5] Size =
92928
WARNING: file compiler/simplCore/SetLevels.lhs line 1022
absVarsOf: discarding info on j_a5Zj
WARNING: file compiler/simplCore/SetLevels.lhs line 1022
absVarsOf: discarding info on n_icU3
WARNING: file compiler/simplCore/SetLevels.lhs line 1022
absVarsOf: discarding info on n_XcV0
WARNING: file compiler/simplCore/SetLevels.lhs line 1022
absVarsOf: discarding info on j_a5Zj
WARNING: file compiler/simplCore/SetLevels.lhs line 1022
absVarsOf: discarding info on n_icU3
WARNING: file compiler/simplCore/SetLevels.lhs line 1022
absVarsOf: discarding info on n_XcV2
WARNING: file compiler/simplCore/SimplCore.lhs line 578
Simplifier baling out after 4 iterations [2261, 32, 16, 10] Size = 144862
WARNING: file compiler/stgSyn/CoreToStg.lhs line 222
lvl7_rjav True False
Interesting! A join var that isn't let-no-escaped
[$j{v spjP} [lid]]
Interesting! A join var that isn't let-no-escaped
[$j{v sp6S} [lid]]
Interesting! A join var that isn't let-no-escaped
[$j{v sjFG} [lid]]
}}}
And, a couple modules later:
At -fsimpl-tick-factor=122, I get this:
{{{
Preprocessing library criterion-0.5.1.0...
Building criterion-0.5.1.0...
[11 of 12] Compiling Criterion ( Criterion.hs,
dist/build/Criterion.o )
WARNING: file compiler/simplCore/SimplCore.lhs line 578
Simplifier baling out after 4 iterations [2752, 252, 55, 60] Size = 2470
WARNING: file compiler/simplCore/SimplCore.lhs line 578
Simplifier baling out after 4 iterations [1166, 95, 21, 5] Size = 2529
ghc: panic! (the 'impossible' happened)
(GHC version 7.3.20111101 for x86_64-apple-darwin):
Simplifier ticks exhausted
When trying RuleFired Class op basicLength
To increase the limit, use -fsimpl-tick-factor=N (default 100)
If you need to do this, let GHC HQ know, and what factor you needed
To see detailed counts use -ddump-simpl-stats
Total ticks: 123423
}}}
At -fsimpl-tick-factor=123, I get this:
{{{
Building criterion-0.5.1.0...
[11 of 12] Compiling Criterion ( Criterion.hs,
dist/build/Criterion.o )
WARNING: file compiler/simplCore/SimplCore.lhs line 578
Simplifier baling out after 4 iterations [2752, 252, 55, 60] Size = 2470
WARNING: file compiler/simplCore/SimplCore.lhs line 578
Simplifier baling out after 4 iterations [1166, 95, 21, 5] Size = 2529
WARNING: file compiler/simplCore/SetLevels.lhs line 1022
absVarsOf: discarding info on n_i3Yc
WARNING: file compiler/simplCore/SetLevels.lhs line 1022
absVarsOf: discarding info on j_i5Zx
WARNING: file compiler/simplCore/SetLevels.lhs line 1022
absVarsOf: discarding info on n_ikeB
WARNING: file compiler/simplCore/SetLevels.lhs line 1022
absVarsOf: discarding info on n_Xkgj
WARNING: file compiler/simplCore/SetLevels.lhs line 1022
absVarsOf: discarding info on j_ibHU
WARNING: file compiler/simplCore/SetLevels.lhs line 1022
absVarsOf: discarding info on n_ikeB
WARNING: file compiler/simplCore/SetLevels.lhs line 1022
absVarsOf: discarding info on n_Xkgl
Interesting! A join var that isn't let-no-escaped
[$j{v sngJ} [lid]]
}}}
--
Ticket URL: <http://hackage.haskell.org/trac/ghc/ticket/5539#comment:13>
GHC <http://www.haskell.org/ghc/>
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