April 2016 - ghc-tickets

Re: [GHC] #5642: Deriving Generic of a big type takes a long time and lots of space
by GHC 28 Apr '16

28 Apr '16

#5642: Deriving Generic of a big type takes a long time and lots of space -------------------------------------+------------------------------------- Reporter: basvandijk | Owner: bgamari Type: bug | Status: new Priority: normal | Milestone: Component: Compiler | Version: 7.3 Resolution: | Keywords: deriving- | perf, Generics Operating System: Unknown/Multiple | Architecture: Type of failure: Compile-time | Unknown/Multiple performance bug | Test Case: T5642 Blocked By: | Blocking: Related Tickets: | Differential Rev(s): Wiki Page: | -------------------------------------+------------------------------------- Comment (by simonpj): Do read comment:8. I think there is something fundamentally difficult here. -- Ticket URL: <http://ghc.haskell.org/trac/ghc/ticket/5642#comment:35> GHC <http://www.haskell.org/ghc/> The Glasgow Haskell Compiler

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Re: [GHC] #4012: Compilation results are not deterministic
by GHC 28 Apr '16

28 Apr '16

#4012: Compilation results are not deterministic -------------------------------------+------------------------------------- Reporter: kili | Owner: niteria Type: bug | Status: new Priority: high | Milestone: 8.2.1 Component: Compiler | Version: 6.12.2 Resolution: | Keywords: Operating System: Unknown/Multiple | Architecture: | Unknown/Multiple Type of failure: Other | Test Case: Blocked By: 11362 | Blocking: Related Tickets: #10424 | Differential Rev(s): Phab:D910, | Phab:D1073, Phab:D1133, Phab:D1192, | Phab:D1268, Phab:D1360, Phab:D1373, Wiki Page: | Phab:D1396, Phab:D1457, Phab:D1468, DeterministicBuilds | Phab:D1487, Phab:D1504, Phab:D1508 -------------------------------------+------------------------------------- Comment (by Bartosz Nitka <niteria@…>): In [changeset:"82538f65f48f370764691264c3c71b975fd43e16/ghc" 82538f65/ghc]: {{{ #!CommitTicketReference repository="ghc" revision="82538f65f48f370764691264c3c71b975fd43e16" Kill varSetElems in injImproveEqns We want to remove varSetElems at the source level because it might be a source of nondeterminism. I don't think it introduces nondeterminism here, but it's easy to do the same thing deterministically for the same price. instFlexiTcS :: [TKVar] -> TcS (TCvSubst, [TcType]) instFlexiTcS currently gives the range of the produced substitution as the second element of the tuple, but it's not used anywhere right now. If it started to be used in the code I'm modifying it would cause nondeterminism problems. Test Plan: ./validate Reviewers: austin, goldfire, bgamari, simonmar, simonpj Reviewed By: simonpj Subscribers: thomie Differential Revision: https://phabricator.haskell.org/D2149 GHC Trac Issues: #4012 }}} -- Ticket URL: <http://ghc.haskell.org/trac/ghc/ticket/4012#comment:154> GHC <http://www.haskell.org/ghc/> The Glasgow Haskell Compiler

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Re: [GHC] #5642: Deriving Generic of a big type takes a long time and lots of space
by GHC 28 Apr '16

28 Apr '16

#5642: Deriving Generic of a big type takes a long time and lots of space -------------------------------------+------------------------------------- Reporter: basvandijk | Owner: bgamari Type: bug | Status: new Priority: normal | Milestone: Component: Compiler | Version: 7.3 Resolution: | Keywords: deriving- | perf, Generics Operating System: Unknown/Multiple | Architecture: Type of failure: Compile-time | Unknown/Multiple performance bug | Test Case: T5642 Blocked By: | Blocking: Related Tickets: | Differential Rev(s): Wiki Page: | -------------------------------------+------------------------------------- Comment (by bgamari): The profile compiling `Data400.hs` from the repo given in comment:33 looks like this, {{{ Wed Apr 27 23:26 2016 Time and Allocation Profiling Report (Final) ghc +RTS -hc -p -RTS -B/opt/exp/ghc/roots/profiled/lib/ghc-8.1.20160222 Data400.hs -fforce- recomp total time = 5.12 secs (5118 ticks @ 1000 us, 1 processor) total alloc = 7,708,824,224 bytes (excludes profiling overheads) COST CENTRE MODULE %time %alloc canEvVar TcCanonical 41.0 45.8 zonkTopDecls TcRnDriver 17.4 25.3 CorePrep HscMain 6.4 7.5 SimplTopBinds SimplCore 5.9 2.6 CoreTidy HscMain 5.5 5.6 Simplify SimplCore 4.2 0.0 deSugar HscMain 3.6 1.7 tc_rn_src_decls TcRnDriver 3.2 2.9 solve_loop TcInteract 2.5 0.7 OccAnal SimplCore 1.6 0.2 pprNativeCode AsmCodeGen 1.1 1.3 }}} -- Ticket URL: <http://ghc.haskell.org/trac/ghc/ticket/5642#comment:34> GHC <http://www.haskell.org/ghc/> The Glasgow Haskell Compiler

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[GHC] #11979: ghc: panic! (the 'impossible' happened)
by GHC 28 Apr '16

28 Apr '16

#11979: ghc: panic! (the 'impossible' happened) -------------------------------------+------------------------------------- Reporter: javierlopm | Owner: Type: bug | Status: new Priority: normal | Milestone: Component: Compiler | Version: 7.6.3 Keywords: panic | Operating System: Linux Architecture: | Type of failure: Documentation Unknown/Multiple | bug Test Case: | Blocked By: Blocking: | Related Tickets: Differential Rev(s): | Wiki Page: -------------------------------------+------------------------------------- Error when compiling, maybe parser wasn't able to detect error at "type TokContent = { position :: Pos, content::String }" ghc: panic! (the 'impossible' happened) (GHC version 7.6.3 for x86_64-unknown-linux): tc_hs_type: record {{{#!hs {-# LANGUAGE DeriveDataTypeable #-} module Tokens( Token (..), Pos ) where import Data.Data(toConstr,Data,Typeable) type Pos = (Int,Int) type TokContent = { position :: Pos, content::String } data Token = TkString { position :: Pos, content::String } | TkLB { position :: Pos, content::String } | TkRB { position :: Pos, content::String } | TkLCurly { position :: Pos, content::String } | TkRCurly { position :: Pos, content::String } | TkLP { position :: Pos, content::String } | TkRP { position :: Pos, content::String } | TkDColon { position :: Pos, content::String } | TkColon { position :: Pos, content::String } | TkSColon { position :: Pos, content::String } | TkTEQ { position :: Pos, content::String } | TkPEQ { position :: Pos, content::String } | TkDot { position :: Pos, content::String } | TkExcMark { position :: Pos, content::String } | TkNEQ { position :: Pos, content::String } | TkDAmp { position :: Pos, content::String } | TkAnd { position :: Pos, content::String } | TkPOr { position :: Pos, content::String } | TkOr { position :: Pos, content::String } | TkDEQ { position :: Pos, content::String } | TkGE { position :: Pos, content::String } | TkLE { position :: Pos, content::String } | TkGT { position :: Pos, content::String } | TkLT { position :: Pos, content::String } | TkIDiv { position :: Pos, content::String } | TkDiv { position :: Pos, content::String } | TkSum { position :: Pos, content::String } | TkMin { position :: Pos, content::String } | TkPower { position :: Pos, content::String } | TkTimes { position :: Pos, content::String } | TkMod { position :: Pos, content::String } | TkEq { position :: Pos, content::String } | TkAssign { position :: Pos, content::String } | TkInt { position :: Pos, content::String } | TkBool { position :: Pos, content::String } | TkChar { position :: Pos, content::String } | TkVoid { position :: Pos, content::String } | TkFloat { position :: Pos, content::String } | TkStruct { position :: Pos, content::String } | TkUnion { position :: Pos, content::String } | TkEnum { position :: Pos, content::String } | TkEnumCons { position :: Pos, content::String } | TkNull { position :: Pos, content::String } | TKGlobal { position :: Pos, content::String } | TkFunc { position :: Pos, content::String } | TkIf { position :: Pos, content::String } | TkElif { position :: Pos, content::String } | TkElse { position :: Pos, content::String } | TkEnd { position :: Pos, content::String } | TkWhile { position :: Pos, content::String } | TkFor { position :: Pos, content::String } | TkBegin { position :: Pos, content::String } | TkBreak { position :: Pos, content::String } | TkContinue { position :: Pos, content::String } | TkReturn { position :: Pos, content::String } | TkExit { position :: Pos, content::String } | TkRead { position :: Pos, content::String } | TkWrite { position :: Pos, content::String } | TkPrint { position :: Pos, content::String } | TkAlloc { position :: Pos, content::String } | TkFree { position :: Pos, content::String } | TkSizeOf { position :: Pos, content::String } | TkGet { position :: Pos, content::String } | TkTruFal { position :: Pos, content::String } | TkNum { position :: Pos, content::Int } | TkDId { position :: Pos, content::String } | TkId { position :: Pos, content::String } | TkError { position :: Pos, content::String } deriving(Data,Typeable) instance Show Token where show generic = show (toConstr generic )++ "\n" ++ " line: " ++ show l ++ "\n" ++ " column: " ++ show c ++ "\n" where (l,c) = position generic }}} -- Ticket URL: <http://ghc.haskell.org/trac/ghc/ticket/11979> GHC <http://www.haskell.org/ghc/> The Glasgow Haskell Compiler

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Re: [GHC] #5642: Deriving Generic of a big type takes a long time and lots of space
by GHC 28 Apr '16

28 Apr '16

#5642: Deriving Generic of a big type takes a long time and lots of space -------------------------------------+------------------------------------- Reporter: basvandijk | Owner: bgamari Type: bug | Status: new Priority: normal | Milestone: Component: Compiler | Version: 7.3 Resolution: | Keywords: deriving- | perf, Generics Operating System: Unknown/Multiple | Architecture: Type of failure: Compile-time | Unknown/Multiple performance bug | Test Case: T5642 Blocked By: | Blocking: Related Tickets: | Differential Rev(s): Wiki Page: | -------------------------------------+------------------------------------- Comment (by nh2): I just filed a duplicate of this (#11991) with another easy-to-run repro that demonstrates that it's precisely O(n²) for sum types: https://github.com/nh2/ghc-generics-deriving-is-slow/ -- Ticket URL: <http://ghc.haskell.org/trac/ghc/ticket/5642#comment:33> GHC <http://www.haskell.org/ghc/> The Glasgow Haskell Compiler

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[GHC] #11991: Generics deriving is quadratic
by GHC 28 Apr '16

28 Apr '16

#11991: Generics deriving is quadratic -------------------------------------+------------------------------------- Reporter: nh2 | Owner: Type: bug | Status: new Priority: normal | Milestone: Component: Compiler | Version: 7.10.3 Keywords: | Operating System: Unknown/Multiple Architecture: | Type of failure: Compile-time Unknown/Multiple | performance bug Test Case: | Blocked By: Blocking: | Related Tickets: Differential Rev(s): | Wiki Page: -------------------------------------+------------------------------------- I'm compiling some code with many sum type alternatives and it's absurdly slow. {{{ {-# LANGUAGE DeriveGeneric #-} import GHC.Generics (Generic) data D = D1 | D2 | ... | D400 deriving (Generic) main = return () }}} I did a little benchmark and it's actually precisely O(n²) in the number of alternatives. Easy repro: https://github.com/nh2/ghc-generics-deriving-is-slow/ I assume that this is a bug and it should be linear. -- Ticket URL: <http://ghc.haskell.org/trac/ghc/ticket/11991> GHC <http://www.haskell.org/ghc/> The Glasgow Haskell Compiler

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[GHC] #11986: Record fields not defined with pattern synonym in ghci
by GHC 27 Apr '16

27 Apr '16

#11986: Record fields not defined with pattern synonym in ghci -------------------------------------+------------------------------------- Reporter: Iceland_jack | Owner: Type: bug | Status: new Priority: normal | Milestone: Component: Compiler | Version: 8.1 Keywords: | Operating System: Unknown/Multiple PatternSynonyms | Architecture: | Type of failure: None/Unknown Unknown/Multiple | Test Case: | Blocked By: Blocking: | Related Tickets: Differential Rev(s): | Wiki Page: -------------------------------------+------------------------------------- Another thing discovered while in the air: When you define pattern synonyms with record syntax, the fields aren't defined in GHCI: {{{#!hs $ ghci -ignore-dot-ghci -XPatternSynonyms GHCi, version 8.1.20160419: http://www.haskell.org/ghc/ :? for help Prelude> pattern Point {x, y} = (x, y) Prelude> :t x <interactive>:1:1: error: Variable not in scope: x Prelude> }}} Works fine when imported from a file. -- Ticket URL: <http://ghc.haskell.org/trac/ghc/ticket/11986> GHC <http://www.haskell.org/ghc/> The Glasgow Haskell Compiler

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Re: [GHC] #4012: Compilation results are not deterministic
by GHC 27 Apr '16

27 Apr '16

#4012: Compilation results are not deterministic -------------------------------------+------------------------------------- Reporter: kili | Owner: niteria Type: bug | Status: new Priority: high | Milestone: 8.2.1 Component: Compiler | Version: 6.12.2 Resolution: | Keywords: Operating System: Unknown/Multiple | Architecture: | Unknown/Multiple Type of failure: Other | Test Case: Blocked By: 11362 | Blocking: Related Tickets: #10424 | Differential Rev(s): Phab:D910, | Phab:D1073, Phab:D1133, Phab:D1192, | Phab:D1268, Phab:D1360, Phab:D1373, Wiki Page: | Phab:D1396, Phab:D1457, Phab:D1468, DeterministicBuilds | Phab:D1487, Phab:D1504, Phab:D1508 -------------------------------------+------------------------------------- Comment (by Bartosz Nitka <niteria@…>): In [changeset:"f13a8d219fbb16ece2bede66ac47f8599a86d3e2/ghc" f13a8d2/ghc]: {{{ #!CommitTicketReference repository="ghc" revision="f13a8d219fbb16ece2bede66ac47f8599a86d3e2" Kill varSetElems in markNominal varSetElems introduces unnecessary nondeterminism and it was straighforward to just get a deterministic list. Test Plan: ./validate Reviewers: austin, goldfire, bgamari, simonmar, simonpj Reviewed By: simonpj Subscribers: thomie Differential Revision: https://phabricator.haskell.org/D2145 GHC Trac Issues: #4012 }}} -- Ticket URL: <http://ghc.haskell.org/trac/ghc/ticket/4012#comment:153> GHC <http://www.haskell.org/ghc/> The Glasgow Haskell Compiler

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Re: [GHC] #4012: Compilation results are not deterministic
by GHC 26 Apr '16

26 Apr '16

#4012: Compilation results are not deterministic -------------------------------------+------------------------------------- Reporter: kili | Owner: niteria Type: bug | Status: new Priority: high | Milestone: 8.2.1 Component: Compiler | Version: 6.12.2 Resolution: | Keywords: Operating System: Unknown/Multiple | Architecture: | Unknown/Multiple Type of failure: Other | Test Case: Blocked By: 11362 | Blocking: Related Tickets: #10424 | Differential Rev(s): Phab:D910, | Phab:D1073, Phab:D1133, Phab:D1192, | Phab:D1268, Phab:D1360, Phab:D1373, Wiki Page: | Phab:D1396, Phab:D1457, Phab:D1468, DeterministicBuilds | Phab:D1487, Phab:D1504, Phab:D1508 -------------------------------------+------------------------------------- Comment (by Bartosz Nitka <niteria@…>): In [changeset:"94320e1d34d14017cc9b38226ea78205a0a76a2b/ghc" 94320e1d/ghc]: {{{ #!CommitTicketReference repository="ghc" revision="94320e1d34d14017cc9b38226ea78205a0a76a2b" Kill varSetElems try_tyvar_defaulting `varSetElems` introduces unnecessary nondeterminism and we can do the same thing deterministically for the same price. Test Plan: ./validate Reviewers: goldfire, austin, simonmar, bgamari, simonpj Reviewed By: simonpj Subscribers: thomie Differential Revision: https://phabricator.haskell.org/D2143 GHC Trac Issues: #4012 }}} -- Ticket URL: <http://ghc.haskell.org/trac/ghc/ticket/4012#comment:152> GHC <http://www.haskell.org/ghc/> The Glasgow Haskell Compiler

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Re: [GHC] #4012: Compilation results are not deterministic
by GHC 26 Apr '16

26 Apr '16

#4012: Compilation results are not deterministic -------------------------------------+------------------------------------- Reporter: kili | Owner: niteria Type: bug | Status: new Priority: high | Milestone: 8.2.1 Component: Compiler | Version: 6.12.2 Resolution: | Keywords: Operating System: Unknown/Multiple | Architecture: | Unknown/Multiple Type of failure: Other | Test Case: Blocked By: 11362 | Blocking: Related Tickets: #10424 | Differential Rev(s): Phab:D910, | Phab:D1073, Phab:D1133, Phab:D1192, | Phab:D1268, Phab:D1360, Phab:D1373, Wiki Page: | Phab:D1396, Phab:D1457, Phab:D1468, DeterministicBuilds | Phab:D1487, Phab:D1504, Phab:D1508 -------------------------------------+------------------------------------- Comment (by Bartosz Nitka <niteria@…>): In [changeset:"2dc5b92e070132114ea1a37f5bd82ab905ff7889/ghc" 2dc5b92/ghc]: {{{ #!CommitTicketReference repository="ghc" revision="2dc5b92e070132114ea1a37f5bd82ab905ff7889" Kill varSetElems in TcErrors The uses of varSetElems in these places are unnecessary and while it doesn't intruduce non-determinism in the ABI the plan is to get rid of all varSetElems to get some compile time guarantees. Test Plan: ./validate Reviewers: austin, simonmar, bgamari, goldfire, simonpj Reviewed By: simonpj Subscribers: thomie Differential Revision: https://phabricator.haskell.org/D2141 GHC Trac Issues: #4012 }}} -- Ticket URL: <http://ghc.haskell.org/trac/ghc/ticket/4012#comment:151> GHC <http://www.haskell.org/ghc/> The Glasgow Haskell Compiler

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