January 2018 - ghc-tickets

[GHC] #14261: ghc stopped recognizing some arm triplets that used to work: Failed to lookup the datalayout for armv7a-hardfloat-linux-gnueabi; available targets:
by GHC 16 Jun '18

16 Jun '18

#14261: ghc stopped recognizing some arm triplets that used to work: Failed to lookup the datalayout for armv7a-hardfloat-linux-gnueabi; available targets: -------------------------------------+------------------------------------- Reporter: slyfox | Owner: (none) Type: bug | Status: new Priority: normal | Milestone: Component: Compiler | Version: 8.3 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: -------------------------------------+------------------------------------- Build failure on current ghc-HEAD as: Build failure for armv7a-hardfloat-linux-gnueabi: {{{ Failed to lookup the datalayout for armv7a-hardfloat-linux-gnueabi; available targets: ["i386-unknown-windows","i686-unknown-windows","x86_64 -unknown-windows","arm-unknown-linux-gnueabihf","armv6-unknown-linux- gnueabihf","armv7-unknown-linux-gnueabihf","aarch64-unknown-linux- gnu","aarch64-unknown-linux","i386-unknown-linux-gnu","i386-unknown- linux","x86_64-unknown-linux-gnu","x86_64-unknown-linux","armv7-unknown- linux-androideabi","aarch64-unknown-linux-android","arm-unknown-nto-qnx- eabi","i386-apple-darwin","x86_64-apple-darwin","armv7-apple-ios","aarch64 -apple-ios","i386-apple-ios","x86_64-apple-ios"] }}} Build failure for armv7a-unknown-linux-gnueabi {{{ Failed to lookup the datalayout for armv7a-unknown-linux-gnueabi; available targets: ["i386-unknown-windows","i686-unknown-windows","x86_64 -unknown-windows","arm-unknown-linux-gnueabihf","armv6-unknown-linux- gnueabihf","armv7-unknown-linux-gnueabihf","aarch64-unknown-linux- gnu","aarch64-unknown-linux","i386-unknown-linux-gnu","i386-unknown- linux","x86_64-unknown-linux-gnu","x86_64-unknown-linux","armv7-unknown- linux-androideabi","aarch64-unknown-linux-android","arm-unknown-nto-qnx- eabi","i386-apple-darwin","x86_64-apple-darwin","armv7-apple-ios","aarch64 -apple-ios","i386-apple-ios","x86_64-apple-ios"] }}} -- Ticket URL: <http://ghc.haskell.org/trac/ghc/ticket/14261> GHC <http://www.haskell.org/ghc/> The Glasgow Haskell Compiler

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[GHC] #14656: Nofib: Ignore cr-lineendings in benchmarks
by GHC 16 Jun '18

16 Jun '18

#14656: Nofib: Ignore cr-lineendings in benchmarks -------------------------------------+------------------------------------- Reporter: AndreasK | Owner: (none) Type: bug | Status: new Priority: normal | Milestone: Component: NoFib | Version: 8.2.2 benchmark suite | Keywords: | Operating System: Windows Architecture: | Type of failure: None/Unknown Unknown/Multiple | Test Case: | Blocked By: Blocking: | Related Tickets: Differential Rev(s): | Wiki Page: -------------------------------------+------------------------------------- At least the real/eff benchmarks fail because of this. {{{ ==nofib== CS: time to run CS follows... ../../../runstdtest/runstdtest ./CS -o1 CS.stdout -o1 CS.stdout -ghc- timing -stdout-binary ; ../../../runstdtest/runstdtest ./CS -o1 CS.stdout -o1 CS.stdout -ghc-timing -stdout-binary ; ../../../runstdtest/runstdtest ./CS -o1 CS.stdout -o1 CS.stdout -ghc- timing -stdout-binary ; ../../../runstdtest/runstdtest ./CS -o1 CS.stdout -o1 CS.stdout -ghc-timing -stdout-binary ; ../../../runstdtest/runstdtest ./CS -o1 CS.stdout -o1 CS.stdout -ghc- timing -stdout-binary ; real 0m0.173s user 0m0.000s sys 0m0.015s ././CS < /dev/null expected stdout not matched by reality <<ghc: 640047168 bytes, 611 GCs (609 + 2), 0/0 avg/max bytes residency (0 samples), 290232 bytes GC work, 2M in use, 0.000 INIT (0.000 elapsed), 0.125 MUT (0.124 elapsed), 0.000 GC (0.001 elapsed), 0.000 GC(0) (0.001 elapsed), 0.000 GC(1) (0.001 elapsed), 1 balance :ghc>> }}} -- Ticket URL: <http://ghc.haskell.org/trac/ghc/ticket/14656> GHC <http://www.haskell.org/ghc/> The Glasgow Haskell Compiler

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[GHC] #13008: Cleanup backwards compatibility ifdefs due to stage1 external interpreter work
by GHC 16 Jun '18

16 Jun '18

#13008: Cleanup backwards compatibility ifdefs due to stage1 external interpreter work -------------------------------------+------------------------------------- Reporter: shlevy | Owner: Type: task | Status: new Priority: normal | Milestone: 8.4.1 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: -------------------------------------+------------------------------------- https://phabricator.haskell.org/D2826 and https://phabricator.haskell.org/D2884 make some code paths that were incompatible with GHC 7.10.x newly built by the stage0 compiler, requiring some CPP hackery to keep our compatibility guarantees. When we can drop that dependency, we should be sure to remove the old code paths. Specifically, the checks for MIN_VERSION_base(4,9,0) and MIN_VERSION_process(1,4,2) can be removed once we're able to assume ghc 8.0.x as stage0. -- Ticket URL: <http://ghc.haskell.org/trac/ghc/ticket/13008> GHC <http://www.haskell.org/ghc/> The Glasgow Haskell Compiler

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[GHC] #12999: Investigate use of floating-point arithmetic in I/O Event-handler
by GHC 16 Jun '18

16 Jun '18

#12999: Investigate use of floating-point arithmetic in I/O Event-handler -------------------------------------+------------------------------------- Reporter: hvr | Owner: Type: task | Status: new Priority: normal | Milestone: 8.2.1 Component: | Version: 8.0.1 libraries/base | 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: -------------------------------------+------------------------------------- I was asked/made aware of some questionable use of floating-point arithmetic in `GHC.Event.TimerManager`; Specifically, I can't explain why `getMonotonicTime` first gets a timestamp as `Word64`, only to perform a not-necessarily cheap floating- point division, and returns a `Double`... {{{#!hs -- | Return monotonic time in seconds, since some unspecified starting point getMonotonicTime :: IO Double getMonotonicTime = do w <- getMonotonicNSec return (fromIntegral w / 1000000000) foreign import ccall unsafe "getMonotonicNSec" getMonotonicNSec :: IO Word64 }}} which then gets used e.g. by {{{#!hs updateTimeout :: TimerManager -> TimeoutKey -> Int -> IO () updateTimeout mgr (TK key) us = do now <- getMonotonicTime let expTime = fromIntegral us / 1000000.0 + now editTimeouts mgr (Q.adjust (const expTime) key) wakeManager mgr }}} Whereas, the priority queue (`GHC.Event.PSQ`) then uses `Double`s for its priorities... For correctness and performance reasons, I'd expect the use of fixed-width integers (i.e. `Word64` or `Int64`) for such codepaths... -- Ticket URL: <http://ghc.haskell.org/trac/ghc/ticket/12999> GHC <http://www.haskell.org/ghc/> The Glasgow Haskell Compiler

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[GHC] #14416: CI with CircleCI
by GHC 16 Jun '18

16 Jun '18

#14416: CI with CircleCI -------------------------------------+------------------------------------- Reporter: chak | Owner: (none) Type: task | Status: new Priority: highest | Milestone: 8.4.1 Component: Build System | Version: Keywords: | Operating System: Unknown/Multiple Architecture: x86_64 | Type of failure: None/Unknown (amd64) | Test Case: | Blocked By: Blocking: | Related Tickets: Differential Rev(s): | Wiki Page: | ContinuousIntegration -------------------------------------+------------------------------------- Merging the PR with the new CircleCI per-commit builds for Linux/x86_64 and macOS/x86_64: https://github.com/ghc/ghc/pull/83 -- Ticket URL: <http://ghc.haskell.org/trac/ghc/ticket/14416> GHC <http://www.haskell.org/ghc/> The Glasgow Haskell Compiler

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[GHC] #14123: Figure out invariants surrounding ticks in Core
by GHC 16 Jun '18

16 Jun '18

#14123: Figure out invariants surrounding ticks in Core -------------------------------------+------------------------------------- Reporter: bgamari | Owner: (none) Type: task | Status: new Priority: highest | Milestone: 8.4.1 Component: Compiler | Version: 8.2.1 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: -------------------------------------+------------------------------------- In the past we have had a number of issues stemming from ticks breaking various Core analyses in GHC, * #13233: a tick separates a levity-polymorphic tycon (e.g. an unboxed tuple tycon) from its levity arguments, resulting in a `typePrimRep` panic. * ticket:8472#comment:22: a tick wraps a primitive string literal, causing `CoreToStg` to fail to notice it is a string resulting in a panic * #14122: Another literal string issue which I have yet to debug but seems very likely to be tick-related. We have merged a stop-gap solution/hack (f5b275a239d2554c4da0b7621211642bf3b10650) to the `ghc-8.2` branch however need a more principled solution in the long-term (e.g. before 8.4). We will need to start by defining precisely where ticks are allowed and add appropriate logic to CoreLint to verify that this invariant is upheld. -- Ticket URL: <http://ghc.haskell.org/trac/ghc/ticket/14123> GHC <http://www.haskell.org/ghc/> The Glasgow Haskell Compiler

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[GHC] #14170: 8.2.1 regression: GHC fails to simplify `natVal`
by GHC 16 Jun '18

16 Jun '18

#14170: 8.2.1 regression: GHC fails to simplify `natVal` -------------------------------------+------------------------------------- Reporter: vagarenko | Owner: (none) Type: bug | Status: new Priority: high | Milestone: 8.2.2 Component: Compiler | Version: 8.2.1 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 GHC 8.2.1 compiles this code with `-O`: {{{#!hs {-# LANGUAGE TypeApplications #-} {-# LANGUAGE TypeInType #-} module NatVal where import Data.Proxy import GHC.TypeLits foo = natVal $ Proxy @0 }}} it produces the following Core: {{{#!hs -- RHS size: {terms: 1, types: 0, coercions: 0, joins: 0/0} NatVal.foo1 :: Integer NatVal.foo1 = 0 -- RHS size: {terms: 41, types: 18, coercions: 0, joins: 0/0} foo :: Integer foo = case NatVal.foo1 of wild_a1iV { integer-gmp-1.0.1.0:GHC.Integer.Type.S# i#_a2ke -> case GHC.Prim.tagToEnum# @ Bool (GHC.Prim.>=# i#_a2ke 0#) of { False -> case GHC.Natural.underflowError of wild2_00 { }; True -> integer-gmp-1.0.1.0:GHC.Integer.Type.wordToInteger (GHC.Prim.int2Word# i#_a2ke) }; integer-gmp-1.0.1.0:GHC.Integer.Type.Jp# dt_a2km -> case GHC.Prim.uncheckedIShiftRL# (GHC.Prim.sizeofByteArray# dt_a2km) 3# of { __DEFAULT -> case GHC.Prim.sizeofByteArray# dt_a2km of { __DEFAULT -> wild_a1iV; 0# -> case GHC.Natural.underflowError of wild4_00 { } }; 1# -> case GHC.Prim.indexWordArray# dt_a2km 0# of wild2_a2kq { __DEFAULT -> integer-gmp-1.0.1.0:GHC.Integer.Type.wordToInteger wild2_a2kq } }; integer-gmp-1.0.1.0:GHC.Integer.Type.Jn# ipv_a2kt -> case GHC.Natural.underflowError of wild1_00 { } } }}} while GHC-8.0.1 does the right thing: {{{#!hs -- RHS size: {terms: 1, types: 0, coercions: 0} foo :: Integer foo = 0 }}} -- Ticket URL: <http://ghc.haskell.org/trac/ghc/ticket/14170> GHC <http://www.haskell.org/ghc/> The Glasgow Haskell Compiler

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[GHC] #13833: Instances with GHC.TypeLits.Nat/Symbol should be possible without FlexibleInstances.
by GHC 15 Jun '18

15 Jun '18

#13833: Instances with GHC.TypeLits.Nat/Symbol should be possible without FlexibleInstances. -------------------------------------+------------------------------------- Reporter: Hjulle | Owner: (none) Type: bug | Status: new Priority: low | Milestone: Component: Compiler | Version: 8.0.2 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: -------------------------------------+------------------------------------- Yes I know, `0` and `"B"` are not technically type constructors, but it's as close as you can get for the kinds Nat and Symbol. Test cases: {{{#!hs {-# LANGUAGE DataKinds, KindSignatures #-} import GHC.TypeLits (Nat, Symbol) class A (n::Nat) instance A 0 class B (s::Symbol) instance B "B" }}} Result: {{{ A.hs:6:10: error: • Illegal instance declaration for ‘A 0’ (All instance types must be of the form (T a1 ... an) where a1 ... an are *distinct type variables*, and each type variable appears at most once in the instance head. Use FlexibleInstances if you want to disable this.) • In the instance declaration for ‘A 0’ A.hs:9:10: error: • Illegal instance declaration for ‘B "B"’ (All instance types must be of the form (T a1 ... an) where a1 ... an are *distinct type variables*, and each type variable appears at most once in the instance head. Use FlexibleInstances if you want to disable this.) • In the instance declaration for ‘B "B"’ }}} -- Ticket URL: <http://ghc.haskell.org/trac/ghc/ticket/13833> GHC <http://www.haskell.org/ghc/> The Glasgow Haskell Compiler

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[GHC] #14747: DisambiguateRecordFields fails for PatternSynonyms
by GHC 15 Jun '18

15 Jun '18

#14747: DisambiguateRecordFields fails for PatternSynonyms -------------------------------------+------------------------------------- Reporter: adamgundry | Owner: (none) Type: bug | Status: new Priority: normal | Milestone: Component: Compiler | Version: 8.2.1 (Type checker) | Keywords: | Operating System: Unknown/Multiple PatternSynonyms | Architecture: | Type of failure: GHC rejects Unknown/Multiple | valid program Test Case: | Blocked By: Blocking: | Related Tickets: #11283 Differential Rev(s): | Wiki Page: -------------------------------------+------------------------------------- Consider: {{{#!hs {-# LANGUAGE PatternSynonyms #-} module A where pattern S{x} = [x] }}} {{{#!hs {-# LANGUAGE PatternSynonyms, DisambiguateRecordFields #-} module B where import A pattern T{x} = [x] e = S { x = 42 } }}} Compiling module B fails with `Ambiguous occurrence ‘x’` in the definition of `e`. In principle, `DisambiguateRecordFields` should select the field belonging to the `S` "data constructor". However, the current implementation of this works by identifying the parent type constructor, which doesn't exist for a pattern synonym. This continues to fail if `T` is replaced by a data type with a field `x`. If `S` is replaced by a data type, however, it starts working. -- Ticket URL: <http://ghc.haskell.org/trac/ghc/ticket/14747> GHC <http://www.haskell.org/ghc/> The Glasgow Haskell Compiler

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[GHC] #13900: Core lint in BuildFlavour=perf-llvm
by GHC 15 Jun '18

15 Jun '18

#13900: Core lint in BuildFlavour=perf-llvm -------------------------------------+------------------------------------- Reporter: bgamari | Owner: (none) Type: bug | Status: new Priority: high | Milestone: 8.4.1 Component: Compiler | Version: 8.3 Keywords: | Operating System: Unknown/Multiple Architecture: | Type of failure: Compile-time Unknown/Multiple | crash or panic Test Case: | Blocked By: Blocking: | Related Tickets: Differential Rev(s): | Wiki Page: -------------------------------------+------------------------------------- I found the following Core lint failure when compiling c9977385dca9536f18374242f713b1048a38dec5 with `BuildFlavour=perf-llvm`, {{{ "inplace/bin/ghc-stage1" -hisuf dyn_hi -osuf dyn_o -hcsuf dyn_hc -fPIC -dynamic -O -H64m -fllvm -Wall -hide-all-packages -i -ighc/. -ighc/stage2/build -Ighc/stage2/build -ighc/stage2/build/ghc/autogen -Ighc/stage2/build/ghc/autogen -optP-DGHCI -optP-include -optPghc/stage2/build/ghc/autogen/cabal_macros.h -package-id base-4.10.0.0 -package-id array-0.5.1.2 -package-id bytestring-0.10.8.2 -package-id directory-1.3.0.2 -package-id process-1.6.0.0 -package-id filepath-1.4.1.2 -package-id ghc-boot-8.3 -package-id ghc-8.3 -package-id unix-2.7.2.2 -package-id containers-0.5.10.2 -package-id deepseq-1.4.3.0 -package-id ghci-8.3 -package-id haskeline-0.7.4.0 -package-id time-1.8.0.1 -package- id transformers-0.5.2.0 -Wall -fno-warn-name-shadowing -XHaskell2010 -O2 -dcore-lint -dcmm-lint -no-hs-main -threaded -no-user-package-db -rtsopts -Wnoncanonical-monad-instances -odir ghc/stage2/build -hidir ghc/stage2/build -stubdir ghc/stage2/build -c ghc/./GHCi/UI/Tags.hs -o ghc/stage2/build/GHCi/UI/Tags.dyn_o *** Core Lint errors : in result of Simplifier *** <no location info>: warning: [RHS of $wgo_XtpE :: [Name] -> Session -> State# RealWorld -> (# State# RealWorld, [[TagInfo]] #)] Rule "SC:$wgo0": lhs type: (# State# RealWorld, [[TagInfo]] #) rhs type: (# State# RealWorld, [Maybe TyThing] #) *** Offending Program *** (see attached) }}} -- Ticket URL: <http://ghc.haskell.org/trac/ghc/ticket/13900> GHC <http://www.haskell.org/ghc/> The Glasgow Haskell Compiler

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