February 2017 - ghc-tickets

[GHC] #8763: forM_ [1..N] does not get fused (10 times slower than go function)
by GHC 13 Oct '18

13 Oct '18

#8763: forM_ [1..N] does not get fused (10 times slower than go function) ------------------------------+-------------------------------------------- Reporter: nh2 | Owner: Type: bug | Status: new Priority: normal | Milestone: Component: Compiler | Version: 7.6.3 Keywords: | Operating System: Unknown/Multiple Architecture: | Type of failure: Runtime performance bug Unknown/Multiple | Test Case: Difficulty: Unknown | Blocking: Blocked By: | Related Tickets: | ------------------------------+-------------------------------------------- Apparently idiomatic code like {{{forM_ [1.._N]}}} does not get fused away. This can give serious performance problems when unnoticed. {{{ -- Slow: forM_ [0.._N-1] $ \i -> do ... -- Around 10 times faster: loop _N $ \i -> do ... {-# INLINE loop #-} loop :: (Monad m) => Int -> (Int -> m ()) -> m () loop bex f = go 0 where go !n | n == bex = return () | otherwise = f n >> go (n+1) }}} Full code example: https://gist.github.com/nh2/8905997 - the relevant alternatives are commented. -- Ticket URL: <http://ghc.haskell.org/trac/ghc/ticket/8763> GHC <http://www.haskell.org/ghc/> The Glasgow Haskell Compiler

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[GHC] #13112: Windows 64-bit GHC HEAD segfaults on the code with a lot of TH stuff.
by GHC 12 Oct '18

12 Oct '18

#13112: Windows 64-bit GHC HEAD segfaults on the code with a lot of TH stuff. --------------------------------------+--------------------------------- Reporter: awson | Owner: Type: bug | Status: new Priority: normal | Milestone: Component: Compiler | Version: 8.1 Keywords: | Operating System: Windows Architecture: x86_64 (amd64) | Type of failure: None/Unknown Test Case: | Blocked By: Blocking: | Related Tickets: Differential Rev(s): | Wiki Page: --------------------------------------+--------------------------------- Currently GHC HEAD segfaults on Windows 64-bit when compiling `language-c-quote-0.11.7.1` package. It spits something like `Access violation in generated code when executing data at 0000000102fbcf40` (I'm using my #13108 patch here). After repeated run, when GHC hasn't recompile all files, but only part of them, it succeeds. If I delete intermediate files and repeat clean compilation, it segfaults again. Haddock always segfaults (since it always recompile all files), more details here: https://github.com/haskell/haddock/pull/568. Since these access violations consistently happen on executable data at virtual addresses above 4GB mark, this very much smells as a GHC bytecode generator/linker issue. I believe, GHC and Haddock succeed exactly when all executable addresses stay below 4GB mark. -- Ticket URL: <http://ghc.haskell.org/trac/ghc/ticket/13112> GHC <http://www.haskell.org/ghc/> The Glasgow Haskell Compiler

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[GHC] #13128: Refactor AvailInfo to be more sensible
by GHC 10 Oct '18

10 Oct '18

#13128: Refactor AvailInfo to be more sensible -------------------------------------+------------------------------------- Reporter: mpickering | Owner: mpickering Type: task | Status: new Priority: low | Milestone: Component: Compiler | Version: 8.0.1 Keywords: | Operating System: Unknown/Multiple Architecture: | Type of failure: None/Unknown Unknown/Multiple | Test Case: | Blocked By: Blocking: | Related Tickets: Differential Rev(s): | Wiki Page: -------------------------------------+------------------------------------- `AvailInfo` has been the bane of my life for the last 12 months and I want to tame it. There are two main problems with it. 1. There is this horrible invariant where if the parent is also exported then it is the first element of the list of children. 2. The set of children and field labels are represented as lists which means many expensive calls to functions from `ListSetOps`. 1 Is easy enough to solve by adding a flag which says whether the parent is exported or not. My naive attempt to solve the second problem was to replace the list by a `NameSet`. At the interface file boundary, the `NameSet` is converted into a list using `nameSetElemsStable` to maintain determinism and only pay the cost of using this expensive function once. This ran into problems in `RnModIface` where there are several functions which map over the list of children. NameSets don't support mapping and so this is difficult to implement in a satisfactory way. The next plan of attack is to distinguish between `IfaceAvailInfo` and `AvailInfo`. The former will use the old representation (lists) in order to maintain determinism but the latter will use sets. Distinguishing the two modes is useful conceptually and practically. The data type is used in quite a few different ways in lots of places which makes writing a nice interface hard. This ticket is to record my trail in case I don't make it to the end. -- Ticket URL: <http://ghc.haskell.org/trac/ghc/ticket/13128> GHC <http://www.haskell.org/ghc/> The Glasgow Haskell Compiler

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[GHC] #11368: Pattern synonym name is mangled when patterns are non-exhaustive
by GHC 10 Oct '18

10 Oct '18

#11368: Pattern synonym name is mangled when patterns are non-exhaustive ---------------------------------------+--------------------------- Reporter: Iceland_jack | Owner: Type: bug | Status: new Priority: low | Milestone: Component: Compiler | Version: 8.1 Keywords: PatternSynonyms | Operating System: Linux Architecture: x86 | Type of failure: Other Test Case: | Blocked By: Blocking: | Related Tickets: #11367 Differential Rev(s): | Wiki Page: ---------------------------------------+--------------------------- {{{ pattern A n <- ... where A 0 = ... }}} When a pattern synonym is non-exhaustive its name is mangled: {{{ >>> A 3 "*** Exception: /tmp/tmp.t0h0pMgwWb.hs:(4,1)-(5,14): Non-exhaustive patterns in function $bA }}} “Non-exhaustive patterns in pattern synonym A” [https://ghc.haskell.org/trac/ghc/ticket/11367?replyto=5#comment:1 Comment] from ticket #11367. -- Ticket URL: <http://ghc.haskell.org/trac/ghc/ticket/11368> GHC <http://www.haskell.org/ghc/> The Glasgow Haskell Compiler

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[GHC] #10783: Partial type signatures should work with pattern synonym signatures
by GHC 10 Oct '18

10 Oct '18

#10783: Partial type signatures should work with pattern synonym signatures -------------------------------------+------------------------------------- Reporter: mpickering | Owner: Type: bug | Status: new Priority: normal | Milestone: Component: Compiler | Version: 7.10.2 Keywords: | Operating System: Unknown/Multiple Architecture: | Type of failure: None/Unknown Unknown/Multiple | Test Case: | Blocked By: Blocking: | Related Tickets: Differential Revisions: | -------------------------------------+------------------------------------- {{{#!hs {-# LANGUAGE PatternSynonyms #-} pattern MyJust :: _ pattern MyJust a = Just a }}} GHC can correctly infer the type for the pattern without the type signature so (to me) it is unexpected that this inferred type is not reported to me when using partial type signatures. It just seems to not be implemented currently. -- Ticket URL: <http://ghc.haskell.org/trac/ghc/ticket/10783> GHC <http://www.haskell.org/ghc/> The Glasgow Haskell Compiler

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[GHC] #12932: -fexternal-interpreter` fails to find symbols
by GHC 08 Oct '18

08 Oct '18

#12932: -fexternal-interpreter` fails to find symbols ----------------------------------------+---------------------------- Reporter: dominic | Owner: Type: bug | Status: new Priority: normal | Milestone: Component: Compiler | Version: 8.0.1 Keywords: | Operating System: MacOS X Architecture: Unknown/Multiple | Type of failure: Other Test Case: | Blocked By: Blocking: | Related Tickets: Differential Rev(s): | Wiki Page: ----------------------------------------+---------------------------- {{{-fexternal-interpreter}}} fails to find symbols but if I run without it all is well. Is this a bug or am I doing something wrong? {{{ ~/Dropbox/Private/Stochastic/demo $ ghci -fexternal-interpreter -prof fe- handling-example.o -i../../monad-bayes/src -package-db=.cabal- sandbox/x86_64-osx-ghc-8.0.1-packages.conf.d -L/usr/local/opt/openblas/lib -lopenblas ghci -fexternal-interpreter -prof fe-handling-example.o -i../../monad- bayes/src -package-db=.cabal-sandbox/x86_64-osx-ghc-8.0.1-packages.conf.d -L/usr/local/opt/openblas/lib -lopenblas GHCi, version 8.0.1: http://www.haskell.org/ghc/ :? for help Prelude> :l app/Main.hs :l app/Main.hs [ 1 of 16] Compiling Control.Monad.Bayes.LogDomain ( ../../monad- bayes/src/Control/Monad/Bayes/LogDomain.hs, interpreted ) [ 2 of 16] Compiling Control.Monad.Bayes.Primitive ( ../../monad- bayes/src/Control/Monad/Bayes/Primitive.hs, interpreted ) [ 3 of 16] Compiling Control.Monad.Bayes.Class ( ../../monad- bayes/src/Control/Monad/Bayes/Class.hs, interpreted ) [ 4 of 16] Compiling Control.Monad.Bayes.Sampler ( ../../monad- bayes/src/Control/Monad/Bayes/Sampler.hs, interpreted ) [ 5 of 16] Compiling Control.Monad.Bayes.Sequential ( ../../monad- bayes/src/Control/Monad/Bayes/Sequential.hs, interpreted ) [ 6 of 16] Compiling Control.Monad.Bayes.Prior ( ../../monad- bayes/src/Control/Monad/Bayes/Prior.hs, interpreted ) [ 7 of 16] Compiling Control.Monad.Bayes.Rejection ( ../../monad- bayes/src/Control/Monad/Bayes/Rejection.hs, interpreted ) [ 8 of 16] Compiling Control.Monad.Bayes.Weighted ( ../../monad- bayes/src/Control/Monad/Bayes/Weighted.hs, interpreted ) [ 9 of 16] Compiling Control.Monad.Bayes.Population ( ../../monad- bayes/src/Control/Monad/Bayes/Population.hs, interpreted ) [10 of 16] Compiling Control.Monad.Bayes.Deterministic ( ../../monad- bayes/src/Control/Monad/Bayes/Deterministic.hs, interpreted ) [11 of 16] Compiling Control.Monad.Bayes.Conditional ( ../../monad- bayes/src/Control/Monad/Bayes/Conditional.hs, interpreted ) [12 of 16] Compiling Control.Monad.Bayes.Dist ( ../../monad- bayes/src/Control/Monad/Bayes/Dist.hs, interpreted ) [13 of 16] Compiling Control.Monad.Bayes.Coprimitive ( ../../monad- bayes/src/Control/Monad/Bayes/Coprimitive.hs, interpreted ) [14 of 16] Compiling Control.Monad.Bayes.Trace ( ../../monad- bayes/src/Control/Monad/Bayes/Trace.hs, interpreted ) [15 of 16] Compiling Control.Monad.Bayes.Inference ( ../../monad- bayes/src/Control/Monad/Bayes/Inference.hs, interpreted ) [16 of 16] Compiling Main ( app/Main.hs, interpreted ) Ok, modules loaded: Main, Control.Monad.Bayes.LogDomain, Control.Monad.Bayes.Primitive, Control.Monad.Bayes.Class, Control.Monad.Bayes.Population, Control.Monad.Bayes.Conditional, Control.Monad.Bayes.Inference, Control.Monad.Bayes.Sampler, Control.Monad.Bayes.Rejection, Control.Monad.Bayes.Weighted, Control.Monad.Bayes.Sequential, Control.Monad.Bayes.Trace, Control.Monad.Bayes.Dist, Control.Monad.Bayes.Prior, Control.Monad.Bayes.Deterministic, Control.Monad.Bayes.Coprimitive. *Main> main main ghc-iserv-prof: lookupSymbol failed in relocateSection (relocate external) /Users/dom/Dropbox/Private/Stochastic/demo/.cabal-sandbox/lib/x86_64-osx- ghc-8.0.1/hmatrix-0.18.0.0-ASQ7f3Yo6PP5MiGTxN80a6/libHShmatrix-0.18.0.0-ASQ7f3Yo6PP5MiGTxN80a6_p.a: unknown symbol `___ieee_divdc3' ghc-iserv-prof: Could not on-demand load symbol '_vectorScan' ghc-iserv-prof: lookupSymbol failed in relocateSection (relocate external) /Users/dom/Dropbox/Private/Stochastic/demo/.cabal-sandbox/lib/x86_64-osx- ghc-8.0.1/hmatrix-0.18.0.0-ASQ7f3Yo6PP5MiGTxN80a6/libHShmatrix-0.18.0.0-ASQ7f3Yo6PP5MiGTxN80a6_p.a: unknown symbol `_vectorScan' ghc-iserv-prof: Could not on-demand load symbol '_hmatrixzm0zi18zi0zi0zmASQ7f3Yo6PP5MiGTxN80a6_InternalziVectorizzed_constantAux_closure' ghc-iserv-prof: lookupSymbol failed in relocateSection (relocate external) /Users/dom/Dropbox/Private/Stochastic/demo/.cabal-sandbox/lib/x86_64-osx- ghc-8.0.1/hmatrix-0.18.0.0-ASQ7f3Yo6PP5MiGTxN80a6/libHShmatrix-0.18.0.0-ASQ7f3Yo6PP5MiGTxN80a6_p.a: unknown symbol `_hmatrixzm0zi18zi0zi0zmASQ7f3Yo6PP5MiGTxN80a6_InternalziVectorizzed_constantAux_closure' ghc-iserv-prof: Could not on-demand load symbol '_hmatrixzm0zi18zi0zi0zmASQ7f3Yo6PP5MiGTxN80a6_InternalziMatrix_Matrix_con_info' ghc-iserv-prof: lookupSymbol failed in relocateSection (relocate external) /Users/dom/Dropbox/Private/Stochastic/demo/.cabal-sandbox/lib/x86_64-osx- ghc-8.0.1/hmatrix-0.18.0.0-ASQ7f3Yo6PP5MiGTxN80a6/libHShmatrix-0.18.0.0-ASQ7f3Yo6PP5MiGTxN80a6_p.a: unknown symbol `_hmatrixzm0zi18zi0zi0zmASQ7f3Yo6PP5MiGTxN80a6_InternalziMatrix_Matrix_con_info' ghc-iserv-prof: Could not on-demand load symbol '_hmatrixzm0zi18zi0zi0zmASQ7f3Yo6PP5MiGTxN80a6_InternalziElement_zgzl_info' ghc-iserv-prof: lookupSymbol failed in relocateSection (relocate external) /Users/dom/Dropbox/Private/Stochastic/demo/.cabal-sandbox/lib/x86_64-osx- ghc-8.0.1/hmatrix-0.18.0.0-ASQ7f3Yo6PP5MiGTxN80a6/libHShmatrix-0.18.0.0-ASQ7f3Yo6PP5MiGTxN80a6_p.a: unknown symbol `_hmatrixzm0zi18zi0zi0zmASQ7f3Yo6PP5MiGTxN80a6_InternalziElement_zgzl_info' ghc-iserv-prof: Could not on-demand load symbol '_hmatrixzm0zi18zi0zi0zmASQ7f3Yo6PP5MiGTxN80a6_InternalziUtil_zdfIndexableVectorDouble_closure' ByteCodeLink.lookupCE During interactive linking, GHCi couldn't find the following symbol: hmatrixzm0zi18zi0zi0zmASQ7f3Yo6PP5MiGTxN80a6_InternalziUtil_zdfIndexableVectorDouble_closure This may be due to you not asking GHCi to load extra object files, archives or DLLs needed by your current session. Restart GHCi, specifying the missing library using the -L/path/to/object/dir and -lmissinglibname flags, or simply by naming the relevant files on the GHCi command line. Alternatively, this link failure might indicate a bug in GHCi. If you suspect the latter, please send a bug report to: glasgow-haskell-bugs(a)haskell.org *Main> }}} But without {{{-fexternal-interpreter}}} all is well. {{{ ~/Dropbox/Private/Stochastic/demo $ ghci -prof fe-handling-example.o -i ../../monad-bayes/src -package-db=.cabal-sandbox/x86_64-osx- ghc-8.0.1-packages.conf.d -L/usr/local/opt/openblas/lib -lopenblas ghci -prof fe-handling-example.o -i../../monad-bayes/src -package-db =.cabal-sandbox/x86_64-osx-ghc-8.0.1-packages.conf.d -L/usr/local/opt/openblas/lib -lopenblas GHCi, version 8.0.1: http://www.haskell.org/ghc/ :? for help Prelude> :l app/Main.hs :l app/Main.hs [ 1 of 16] Compiling Control.Monad.Bayes.LogDomain ( ../../monad- bayes/src/Control/Monad/Bayes/LogDomain.hs, interpreted ) [ 2 of 16] Compiling Control.Monad.Bayes.Primitive ( ../../monad- bayes/src/Control/Monad/Bayes/Primitive.hs, interpreted ) [ 3 of 16] Compiling Control.Monad.Bayes.Class ( ../../monad- bayes/src/Control/Monad/Bayes/Class.hs, interpreted ) [ 4 of 16] Compiling Control.Monad.Bayes.Sampler ( ../../monad- bayes/src/Control/Monad/Bayes/Sampler.hs, interpreted ) [ 5 of 16] Compiling Control.Monad.Bayes.Sequential ( ../../monad- bayes/src/Control/Monad/Bayes/Sequential.hs, interpreted ) [ 6 of 16] Compiling Control.Monad.Bayes.Prior ( ../../monad- bayes/src/Control/Monad/Bayes/Prior.hs, interpreted ) [ 7 of 16] Compiling Control.Monad.Bayes.Rejection ( ../../monad- bayes/src/Control/Monad/Bayes/Rejection.hs, interpreted ) [ 8 of 16] Compiling Control.Monad.Bayes.Weighted ( ../../monad- bayes/src/Control/Monad/Bayes/Weighted.hs, interpreted ) [ 9 of 16] Compiling Control.Monad.Bayes.Population ( ../../monad- bayes/src/Control/Monad/Bayes/Population.hs, interpreted ) [10 of 16] Compiling Control.Monad.Bayes.Deterministic ( ../../monad- bayes/src/Control/Monad/Bayes/Deterministic.hs, interpreted ) [11 of 16] Compiling Control.Monad.Bayes.Conditional ( ../../monad- bayes/src/Control/Monad/Bayes/Conditional.hs, interpreted ) [12 of 16] Compiling Control.Monad.Bayes.Dist ( ../../monad- bayes/src/Control/Monad/Bayes/Dist.hs, interpreted ) [13 of 16] Compiling Control.Monad.Bayes.Coprimitive ( ../../monad- bayes/src/Control/Monad/Bayes/Coprimitive.hs, interpreted ) [14 of 16] Compiling Control.Monad.Bayes.Trace ( ../../monad- bayes/src/Control/Monad/Bayes/Trace.hs, interpreted ) [15 of 16] Compiling Control.Monad.Bayes.Inference ( ../../monad- bayes/src/Control/Monad/Bayes/Inference.hs, interpreted ) [16 of 16] Compiling Main ( app/Main.hs, interpreted ) Ok, modules loaded: Main, Control.Monad.Bayes.LogDomain, Control.Monad.Bayes.Primitive, Control.Monad.Bayes.Class, Control.Monad.Bayes.Population, Control.Monad.Bayes.Conditional, Control.Monad.Bayes.Inference, Control.Monad.Bayes.Sampler, Control.Monad.Bayes.Rejection, Control.Monad.Bayes.Weighted, Control.Monad.Bayes.Sequential, Control.Monad.Bayes.Trace, Control.Monad.Bayes.Dist, Control.Monad.Bayes.Prior, Control.Monad.Bayes.Deterministic, Control.Monad.Bayes.Coprimitive. *Main> main main Old State: S {p = 96.41248458072532, z = 59.16931688468654, log_alpha = -3.3251317115519465} New state: S {p = 85.18277032500659, z = 47.518663747379414, log_alpha = -0.8056624325046409} Old State: S {p = 110.26606081933504, z = 47.25472896292412, log_alpha = -7.942692650345256} New state: S {p = 99.8466327066433, z = 38.81428385855752, log_alpha = -0.712367347081303} Old State: S {p = 101.53403093173365, z = 54.69189565042656, log_alpha = 0.797288536547407} New state: S {p = 101.52281529166201, z = 44.30057747486097, log_alpha = -2.015330785654092} Old State: S {p = 77.31689464064326, z = 46.619899785065876, log_alpha = 2.2759251158534526} New state: S {p = 116.2875593953072, z = 38.966471329788355, log_alpha = -0.7142394862058071} Old State: S {p = 76.9380013726558, z = 50.125629063113514, log_alpha = -3.2499432321011583} New state: S {p = 69.40844025380522, z = 41.55282023557805, log_alpha = -3.0159942091527503e-2} Old State: S {p = 69.40844025380522, z = 41.55282023557805, log_alpha = -3.0159942091527503e-2} New state: S {p = 68.03763906369906, z = 35.283787110815105, log_alpha = 1.3054304633451674} Old State: S {p = 69.40844025380522, z = 41.55282023557805, log_alpha = -3.0159942091527503e-2} New state: S {p = 68.03763906369906, z = 35.283787110815105, log_alpha = -0.9916988019989725} Old State: S {p = 69.40844025380522, z = 41.55282023557805, log_alpha = -3.0159942091527503e-2} New state: S {p = 68.03763906369906, z = 35.283787110815105, log_alpha = -3.611295894501775} Old State: S {p = 69.40844025380522, z = 41.55282023557805, log_alpha = -3.0159942091527503e-2} New state: S {p = 68.03763906369906, z = 35.283787110815105, log_alpha = -0.7617210597518349} Old State: S {p = 116.2875593953072, z = 38.966471329788355, log_alpha = -0.7142394862058071} New state: S {p = 109.6078122188652, z = 32.55851436113107, log_alpha = -0.4233108619474501} Old State: S {p = 68.03763906369906, z = 35.283787110815105, log_alpha = 1.3054304633451674} New state: S {p = 79.79830336014518, z = 30.422294131721443, log_alpha = 0.6993690927536277} Old State: S {p = 68.03763906369906, z = 35.283787110815105, log_alpha = -0.9916988019989725} New state: S {p = 64.90164005295357, z = 30.422294131721443, log_alpha = -0.3152970276116467} Old State: S {p = 68.03763906369906, z = 35.283787110815105, log_alpha = -0.9916988019989725} New state: S {p = 64.90164005295357, z = 30.422294131721443, log_alpha = -0.8415339406842459} Old State: S {p = 68.03763906369906, z = 35.283787110815105, log_alpha = 1.3054304633451674} New state: S {p = 79.79830336014518, z = 30.422294131721443, log_alpha = -0.755338763976243} Old State: S {p = 68.03763906369906, z = 35.283787110815105, log_alpha = -0.9916988019989725} New state: S {p = 64.90164005295357, z = 30.422294131721443, log_alpha = -0.12244882682932601} Old State: S {p = 103.98419668715715, z = 51.46501997223569, log_alpha = NaN} New state: S {p = NaN, z = 41.96850310814045, log_alpha = -2.6446936218209336} Old State: S {p = 101.59457288618177, z = 50.895296415987694, log_alpha = NaN} New state: S {p = NaN, z = 41.61054780428653, log_alpha = -3.429882621028084} Old State: S {p = 87.94516676609489, z = 49.33016788299561, log_alpha = NaN} New state: S {p = NaN, z = 40.75469030451892, log_alpha = -0.3548643358912281} Old State: S {p = 85.99795164317248, z = 49.168021162595345, log_alpha = NaN} New state: S {p = NaN, z = 40.67497206346814, log_alpha = 2.1104720283005785} Old State: S {p = 78.54647250550833, z = 42.630247908299566, log_alpha = NaN} New state: S {p = NaN, z = 35.95097968042852, log_alpha = -0.6513484233809421} Old State: S {p = NaN, z = 40.75469030451892, log_alpha = -0.3548643358912281} New state: S {p = NaN, z = NaN, log_alpha = -1.5720943792122584} Old State: S {p = NaN, z = 40.75469030451892, log_alpha = -0.3548643358912281} New state: S {p = NaN, z = NaN, log_alpha = -1.6631770526157945} Old State: S {p = NaN, z = 40.67497206346814, log_alpha = 2.1104720283005785} New state: S {p = NaN, z = NaN, log_alpha = -1.2345329390236304} Old State: S {p = NaN, z = 35.95097968042852, log_alpha = -0.6513484233809421} New state: S {p = NaN, z = NaN, log_alpha = -1.820929341136602} Old State: S {p = NaN, z = 40.67497206346814, log_alpha = 2.1104720283005785} New state: S {p = NaN, z = NaN, log_alpha = -2.520535318849168} Old State: S {p = NaN, z = NaN, log_alpha = -1.5720943792122584} New state: S {p = NaN, z = NaN, log_alpha = -0.9471390581854239} Old State: S {p = NaN, z = NaN, log_alpha = -1.6631770526157945} New state: S {p = NaN, z = NaN, log_alpha = -1.0755021237404696} Old State: S {p = NaN, z = NaN, log_alpha = -1.2345329390236304} New state: S {p = NaN, z = NaN, log_alpha = -1.1239335260594507} Old State: S {p = NaN, z = NaN, log_alpha = -1.820929341136602} New state: S {p = NaN, z = NaN, log_alpha = -1.2944498914356701} Old State: S {p = NaN, z = NaN, log_alpha = -2.520535318849168} New state: S {p = NaN, z = NaN, log_alpha = -0.27411572356967484} Accept: False Old State: S {p = 111.8506804060528, z = 49.43995360167743, log_alpha = -9.192660539879242} New state: S {p = 100.79139727821112, z = 40.36178045350178, log_alpha = 1.3407944594098864} Old State: S {p = 112.56620850387993, z = 51.36209895306485, log_alpha = -2.625437037736268} New state: S {p = 101.35925858189091, z = 41.718829881234356, log_alpha = -0.7240542276022712} Old State: S {p = 124.03888190950703, z = 60.73043151177312, log_alpha = -5.946495216000299} New state: S {p = 108.98533165239414, z = 47.91166969904897, log_alpha = -0.8873500091662709} Old State: S {p = 98.02675197633516, z = 52.91365067391672, log_alpha = 2.312571443928833} New state: S {p = 138.1350004691826, z = 43.12261446736768, log_alpha = -0.2792667910662988} Old State: S {p = 94.54575888175407, z = 42.83674832921917, log_alpha = -7.3217354704711175} New state: S {p = 86.44898836218327, z = 35.83329122968358, log_alpha = -0.6931069199421952} Old State: S {p = 86.44898836218327, z = 35.83329122968358, log_alpha = -0.6931069199421952} New state: S {p = 82.70767613536381, z = 30.592809349196145, log_alpha = 0.3349397265296642} Old State: S {p = 86.44898836218327, z = 35.83329122968358, log_alpha = -0.6931069199421952} New state: S {p = 82.70767613536381, z = 30.592809349196145, log_alpha = -1.3495963112508207} Old State: S {p = 138.1350004691826, z = 43.12261446736768, log_alpha = -0.2792667910662988} New state: S {p = 129.45324316753013, z = 35.29589318379763, log_alpha = -0.386669465854595} Old State: S {p = 138.1350004691826, z = 43.12261446736768, log_alpha = -0.2792667910662988} New state: S {p = 129.45324316753013, z = 35.29589318379763, log_alpha = -0.2946746748816039} Old State: S {p = 138.1350004691826, z = 43.12261446736768, log_alpha = -0.2792667910662988} New state: S {p = 129.45324316753013, z = 35.29589318379763, log_alpha = 6.008701708774278e-2} Old State: S {p = 82.70767613536381, z = 30.592809349196145, log_alpha = 0.3349397265296642} New state: S {p = 84.42743985481702, z = 26.485152940386072, log_alpha = -0.8565266788034482} Old State: S {p = 82.70767613536381, z = 30.592809349196145, log_alpha = -1.3495963112508207} New state: S {p = 78.90510523061384, z = 26.485152940386072, log_alpha = -0.23947594100584424} Old State: S {p = 82.70767613536381, z = 30.592809349196145, log_alpha = -1.3495963112508207} New state: S {p = 78.90510523061384, z = 26.485152940386072, log_alpha = -1.6400685168014388} Old State: S {p = 82.70767613536381, z = 30.592809349196145, log_alpha = -1.3495963112508207} New state: S {p = 78.90510523061384, z = 26.485152940386072, log_alpha = -2.309718174473867} Old State: S {p = 82.70767613536381, z = 30.592809349196145, log_alpha = 0.3349397265296642} New state: S {p = 84.42743985481702, z = 26.485152940386072, log_alpha = 0.39960426429090445} Old State: S {p = 103.15456652417501, z = 48.70703230482669, log_alpha = 3.261489684559035} New state: S {p = 223.41791271148057, z = 40.00425989911341, log_alpha = -1.6654810839749887} Old State: S {p = 78.21539356172975, z = 49.34769089107648, log_alpha = 2.9941081783405235} New state: S {p = 165.5956281460007, z = 40.9594944371077, log_alpha = -0.6807278054716505} Old State: S {p = 121.27107377910983, z = 50.9432853913191, log_alpha = -8.126318808529764} New state: S {p = 108.916591323712, z = 41.2439385542472, log_alpha = 0.4369643557823619} Old State: S {p = 98.33533600637841, z = 50.915794054555995, log_alpha = -0.47638340582836275} New state: S {p = 91.42595876935069, z = 41.6915974374073, log_alpha = -1.570488913622821} Old State: S {p = 106.35901771371051, z = 58.39939541846798, log_alpha = 2.4859548939567686} New state: S {p = 153.7564635774571, z = 46.75791989853097, log_alpha = -0.7265425179819862} Old State: S {p = 165.5956281460007, z = 40.9594944371077, log_alpha = -0.6807278054716505} New state: S {p = 153.47230437543251, z = 33.25266900659429, log_alpha = -1.6781162212290632} Old State: S {p = 165.5956281460007, z = 40.9594944371077, log_alpha = -0.6807278054716505} New state: S {p = 153.47230437543251, z = 33.25266900659429, log_alpha = 0.7148953771487301} Old State: S {p = 165.5956281460007, z = 40.9594944371077, log_alpha = -0.6807278054716505} New state: S {p = 153.47230437543251, z = 33.25266900659429, log_alpha = 1.2994581914331431} Old State: S {p = 165.5956281460007, z = 40.9594944371077, log_alpha = -0.6807278054716505} New state: S {p = 153.47230437543251, z = 33.25266900659429, log_alpha = -0.6908099313919266} Old State: S {p = 165.5956281460007, z = 40.9594944371077, log_alpha = -0.6807278054716505} New state: S {p = 153.47230437543251, z = 33.25266900659429, log_alpha = 0.6115450247483429} Old State: S {p = 153.47230437543251, z = 33.25266900659429, log_alpha = 0.6115450247483429} New state: S {p = 149.84673299439467, z = 27.669736758576065, log_alpha = 2.249112097719827} Old State: S {p = 153.47230437543251, z = 33.25266900659429, log_alpha = 0.7148953771487301} New state: S {p = 150.56328821556426, z = 27.669736758576065, log_alpha = -1.6634676360703886} Old State: S {p = 153.47230437543251, z = 33.25266900659429, log_alpha = 0.6115450247483429} New state: S {p = 149.84673299439467, z = 27.669736758576065, log_alpha = -1.1143896901497614} Old State: S {p = 153.47230437543251, z = 33.25266900659429, log_alpha = -1.6781162212290632} New state: S {p = 143.93225309113896, z = 27.669736758576065, log_alpha = 1.2174133795952156} Old State: S {p = 153.47230437543251, z = 33.25266900659429, log_alpha = -1.6781162212290632} New state: S {p = 143.93225309113896, z = 27.669736758576065, log_alpha = 0.2956142597127277} Accept: False 4.962072576592402e-2 7.408640679453008 *Main> }}} -- Ticket URL: <http://ghc.haskell.org/trac/ghc/ticket/12932> GHC <http://www.haskell.org/ghc/> The Glasgow Haskell Compiler

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[GHC] #12469: Memory fence on writeIORef missing on ARM
by GHC 06 Oct '18

06 Oct '18

#12469: Memory fence on writeIORef missing on ARM ------------------------------------+------------------------------------- Reporter: rrnewton | Owner: Type: bug | Status: new Priority: normal | Milestone: 8.2.1 Component: Compiler | Version: 8.0.1 Keywords: memory model | Operating System: Unknown/Multiple Architecture: arm | Type of failure: None/Unknown Test Case: | Blocked By: Blocking: | Related Tickets: Differential Rev(s): | Wiki Page: ------------------------------------+------------------------------------- The memory model question has been debated now and again. his thread from ten years back (https://mail.haskell.org/pipermail/haskell-prime/2006-April/001237.html) lays out the basic situation with thunk update, writeIORef, and memory fences. But we recently began experimenting with GHC on ARM platforms, and it seems to lack a memory fence that the participants in the cited thread expect it to have. Here's an attempt to construct a program which writes fields of a data structure, and then writes the pointer to that structure to an IORef, without the proper fence inbetween: ```Haskell import Data.IORef import Control.Concurrent data Foo = Foo Int deriving Show {-# NOINLINE mkfoo #-} mkfoo x = Foo x {-# NOINLINE dowrite #-} dowrite r n = writeIORef r $! mkfoo n main = do r <- newIORef (Foo 3) forkIO (dowrite r 4) x <- readIORef r print x ``` Here's the relevant bits of the CMM that results when compiled on an ARM 64 machine: ```C mkfoo_rn1_entry() // [] { [] } {offset c40i: P64[MainCapability+872] = P64[MainCapability+872] + 16; if (P64[MainCapability+872] > I64[MainCapability+880]) goto c40m; else goto c40l; c40m: I64[MainCapability+928] = 16; P64[MainCapability+24] = mkfoo_rn1_closure; call (I64[MainCapability+16])(R1) args: 16, res: 0, upd: 8; c40l: I64[P64[MainCapability+872] - 8] = Foo_con_info; P64[P64[MainCapability+872]] = P64[I64[MainCapability+856]]; P64[MainCapability+24] = P64[MainCapability+872] - 7; I64[MainCapability+856] = I64[MainCapability+856] + 8; call (I64[P64[I64[MainCapability+856]]])(R1) args: 8, res: 0, upd: 8; } } ``` ```C dowrite_entry() // [] { [] } {offset c44j: call a_r3Dy_entry() args: 24, res: 0, upd: 8; } } a_r3Dy_entry() // [R1] { [] } {offset c41D: if (I64[MainCapability+856] - 16 < I64[MainCapability+864]) goto c41H; else goto c41I; c41H: P64[MainCapability+24] = a_r3Dy_closure; call (I64[MainCapability+16])(R1) args: 24, res: 0, upd: 8; c41I: I64[I64[MainCapability+856] - 8] = block_c41B_info; P64[I64[MainCapability+856] - 16] = P64[I64[MainCapability+856] + 8]; I64[MainCapability+856] = I64[MainCapability+856] - 16; call mkfoo_rn1_entry() args: 16, res: 8, upd: 8; } } block_c41B_entry() // [R1] { [] } {offset c41B: _s3Ep::P64 = P64[I64[MainCapability+856] + 8]; I64[I64[MainCapability+856] + 8] = block_c41G_info; _s3Es::P64 = P64[MainCapability+24]; P64[MainCapability+24] = _s3Ep::P64; P64[I64[MainCapability+856] + 16] = _s3Es::P64; I64[MainCapability+856] = I64[MainCapability+856] + 8; if (P64[MainCapability+24] & 7 != 0) goto u41S; else goto c41K; u41S: call block_c41G_entry(R1) args: 0, res: 0, upd: 0; c41K: call (I64[I64[P64[MainCapability+24]]])(R1) args: 8, res: 8, upd: 8; } } block_c41G_entry() // [R1] { [] } {offset c41G: _s3Ev::P64 = P64[P64[MainCapability+24] + 7]; P64[_s3Ev::P64 + 8] = P64[I64[MainCapability+856] + 8]; call "ccall" arg hints: [PtrHint, PtrHint] result hints: [] dirty_MUT_VAR(MainCapability+24, _s3Ev::P64); P64[MainCapability+24] = ()_closure+1; I64[MainCapability+856] = I64[MainCapability+856] + 16; call (I64[P64[I64[MainCapability+856]]])(R1) args: 8, res: 0, upd: 8; } } ``` The fence should happen before the write of the pointer into the IORef. I can't find the fence, and can't find a codepath in the compiler that would insert it (i.e. with MO_WriteBarrier). `dirty_MUT_VAR` is actually too late to perform the fence, but it doesn't either: ```C void dirty_MUT_VAR(StgRegTable *reg, StgClosure *p) { Capability *cap = regTableToCapability(reg); if (p->header.info == &stg_MUT_VAR_CLEAN_info) { p->header.info = &stg_MUT_VAR_DIRTY_info; recordClosureMutated(cap,p); } } ``` (Neither does `recordClosureMutated`.) -- Ticket URL: <http://ghc.haskell.org/trac/ghc/ticket/12469> GHC <http://www.haskell.org/ghc/> The Glasgow Haskell Compiler

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[GHC] #8708: Kind annotation in tuple not parsed
by GHC 04 Oct '18

04 Oct '18

#8708: Kind annotation in tuple not parsed -------------------------------------+------------------------------------- Reporter: goldfire | Owner: Type: bug | Status: new Priority: normal | Milestone: Component: Compiler (Parser) | Version: 7.7 Keywords: | Operating System: Unknown/Multiple Architecture: Unknown/Multiple | Type of failure: None/Unknown Difficulty: Unknown | Test Case: Blocked By: | Blocking: Related Tickets: | -------------------------------------+------------------------------------- Consider this: {{{ {-# LANGUAGE KindSignatures #-} foo :: (Int, Int :: *) foo = undefined }}} HEAD reports {{{ /Users/rae/temp/Bug.hs:5:18: parse error on input ‛::’ }}} Changing the line to {{{ foo :: (Int, (Int :: *)) }}} fixes the problem. Note the extra parentheses. -- Ticket URL: <http://ghc.haskell.org/trac/ghc/ticket/8708> GHC <http://www.haskell.org/ghc/> The Glasgow Haskell Compiler

1 5

[GHC] #11622: Annotating types in type familiy equations without parentheses
by GHC 04 Oct '18

04 Oct '18

#11622: Annotating types in type familiy equations without parentheses -------------------------------------+------------------------------------- Reporter: Iceland_jack | Owner: Type: bug | Status: new Priority: normal | Milestone: Component: Compiler | Version: 8.1 Keywords: | Operating System: Unknown/Multiple Architecture: | Type of failure: None/Unknown Unknown/Multiple | Test Case: | Blocked By: Blocking: | Related Tickets: Differential Rev(s): | Wiki Page: -------------------------------------+------------------------------------- When annotating types in right-hand side of type family equations parentheses are required: {{{#!hs type family F a where F _ = (Int :: Type) }}} instead of {{{#!hs type family F a where F _ = Int :: Type }}} -- Ticket URL: <http://ghc.haskell.org/trac/ghc/ticket/11622> GHC <http://www.haskell.org/ghc/> The Glasgow Haskell Compiler

1 6

[GHC] #11251: isInstance does not work on Typeable with base-4.8 anymore
by GHC 04 Oct '18

04 Oct '18

#11251: isInstance does not work on Typeable with base-4.8 anymore -------------------------------------+------------------------------------- Reporter: songzh | Owner: Type: bug | Status: new Priority: normal | Milestone: Component: | Version: 7.10.1 libraries/base | Keywords: Typeable, | Operating System: Unknown/Multiple isInstance | Architecture: | Type of failure: None/Unknown Unknown/Multiple | Test Case: | Blocked By: Blocking: | Related Tickets: Differential Rev(s): | Wiki Page: -------------------------------------+------------------------------------- {{{#!hs > :set -XTemplateHaskell > :m +Data.Tyepable > :m +Language.Haskell.TH --- With GHC 7.8 or earlier versions of GHC (I only tried with GHC 7.6, but my friends tried on 7.8 and earlier versoin) > $(isInstance ''Typeable [ConT ''Char] >>= stringE.show) "True" --- With GHC 7.10.1 > $(isInstance ''Typeable [ConT ''Char] >>= stringE.show) "False" }}} I have noticed that standalone derivings of Typeable instances in Data.Typeable are disappared magically in base-4.8 of GHC 7.10,also one cannot query the instances of it by using `:i Typeable` in GHCi, however, obviously, I can use `typeOf` function in base-4.8 to get the TypeRep of Char. The problem is that `isInstance` in template-haskell library doesn't know Char and many other types are instances of Typeable anymore. -- Ticket URL: <http://ghc.haskell.org/trac/ghc/ticket/11251> GHC <http://www.haskell.org/ghc/> The Glasgow Haskell Compiler

1 8