June 2018 - ghc-tickets

[GHC] #14859: Allow explicit impredicativity
by GHC 25 Oct '18

25 Oct '18

#14859: Allow explicit impredicativity -------------------------------------+------------------------------------- Reporter: simonpj | Owner: (none) Type: bug | Status: new Priority: normal | Milestone: Component: Compiler | Version: 8.2.2 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: -------------------------------------+------------------------------------- In [https://mail.haskell.org/pipermail/ghc-devs/2016-September/012940.html this email] I suggested allowing a simple form of impredicativity. With a suitable extension flag (`-XExplicitImpredicativeTypes` perhaps), you woudl be allowed: * To write a polytype in a visible type argument; eg. `f @(forall a. a->a)` * To write a polytype as an argument of a type in a signature e.g. `f :: [forall a. a->a] -> Int` ''But that’s all''. A unification variable still cannot be unified with a polytype. The only way you can call a polymorphic function at a polytype is to use Visible Type Application (VTA). So using impredicative types might be tiresome. E.g. {{{ type SID = forall a. a->a xs :: [forall a. a->a] xs = (:) @SID id ( (:) @SID id ([] @ SID)) }}} In short, if you call a function at a polytype, you must use VTA. Simple, easy, predictable; and doubtless annoying. But at least it's possible. The main motivation is that we are naughtily doing this anyway in the implementation of `GeneralisedNewtypeDeriving` -- see Trac #14070 comment:23 ff. If we are doing it under the hood, we could just made it available to programmers. This is much less ambitious, and much easier to implement, than the proposed [https://www.microsoft.com/en-us/research/publication/guarded- impredicative-polymorphism/ Guarded impredicative polymorphism] (PLDI'18). This ticket just records the idea, to see what other use-cases people might want to add. Then someone would have to write a GHC proposal. -- Ticket URL: <http://ghc.haskell.org/trac/ghc/ticket/14859> GHC <http://www.haskell.org/ghc/> The Glasgow Haskell Compiler

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[GHC] #15300: Unboxed Sums Crash
by GHC 25 Oct '18

25 Oct '18

#15300: Unboxed Sums Crash -------------------------------------+------------------------------------- Reporter: andrewthad | Owner: (none) Type: task | Status: new Priority: normal | Milestone: 8.6.1 Component: Compiler | Version: 8.4.3 Keywords: UnboxedSums | 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've made it a little further in my experiments with unboxed tuples in the `packed` library. However, I've run into another issue that I strongly suspect is the result of bad behavior of unboxed tuples. To replicate this issue (with GHC 8.4.3), do the following: {{{ git clone https://github.com/andrewthad/packed cd packed cabal new-build }}} We use `cabal new-build` for its side effect of creating a `.ghc.environment.xyz` file. Now, create a minimal example in the directory called `eol.hs` with the following contents: {{{ import Packed.Bytes.Parser (Parser) import Data.Word import Packed.Bytes (Bytes) import GHC.Exts (RealWorld) import Packed.Bytes.Stream.IO (ByteStream) import qualified Packed.Bytes as B import qualified Data.Char import qualified Packed.Bytes.Parser as P import qualified Packed.Bytes.Stream.IO as Stream main :: IO () main = do r <- runExampleParser ( do P.takeBytesUntilEndOfLineConsume P.takeBytesUntilEndOfLineConsume P.takeBytesUntilEndOfLineConsume ) (foldMap Stream.singleton (map charToWord8 "the\nemporium\rhas\narrived")) print r runExampleParser :: Parser e () a -> ByteStream RealWorld -> IO (Maybe a, Maybe String) runExampleParser parser stream = do P.Result mleftovers r _ <- P.parseStreamIO stream () parser mextra <- case mleftovers of Nothing -> return Nothing Just (P.Leftovers chunk remainingStream) -> do bs <- Stream.unpack remainingStream return (Just (map word8ToChar (B.unpack chunk ++ bs))) return (either (const Nothing) Just r,mextra) word8ToChar :: Word8 -> Char word8ToChar = Data.Char.chr . fromIntegral charToWord8 :: Char -> Word8 charToWord8 = fromIntegral . Data.Char.ord s2b :: String -> Bytes s2b = B.pack . map charToWord8 c2w :: Char -> Word8 c2w = charToWord8 }}} Finally, build this with `ghc -O2 eol.hs`, and then run the executable this produces to get the following: {{{ (Nothing,Just "\rhas\narrived") eol: internal error: stg_ap_n_ret (GHC version 8.4.3 for x86_64_unknown_linux) Please report this as a GHC bug: http://www.haskell.org/ghc/reportabug Aborted (core dumped) }}} Things worth noting: 1. I think the program fails in the final GC that runs right before the program terminates. We can see that it produces a correct result of `(Nothing,Just "\rhas\narrived")`, but something on the heap has definitely been corrupted. 2. This only happens with `-O2` turned on. 3. This only happens when the parser does not successfully parse its input. Here's some more context around this. I've been working on a parser that uses unboxed sums instead of continuations. After #15038 was fixed, everything had been going well. Then, I took the parser type and added two things to it: (1) context and (2) typed errors. Context is basically like throwing `StateT` on top and errors are like throwing `ExceptT` on top. After this, everything in my test suite kept working except for a single test, which now consistently crashes my test suite. So, I originally had this: {{{ type Bytes# = (# ByteArray#, Int#, Int# #) type Maybe# (a :: TYPE r) = (# (# #) | a #) type Leftovers# s = (# Bytes# , ByteStream s #) type Result# s (r :: RuntimeRep) (a :: TYPE r) = (# Maybe# (Leftovers# s), Maybe# a #) newtype ParserLevity (r :: RuntimeRep) (a :: TYPE r) = ParserLevity { getParserLevity :: forall s. Maybe# (Leftovers# s) -> State# s -> (# State# s, Result# s r a #) } }}} But I changed it to this: {{{ type Bytes# = (# ByteArray#, Int#, Int# #) type Maybe# (a :: TYPE r) = (# (# #) | a #) type Either# a (b :: TYPE r) = (# a | b #) type Leftovers# s = (# Bytes# , ByteStream s #) type Result# e c s (r :: RuntimeRep) (a :: TYPE r) = (# Maybe# (Leftovers# s), Either# (Maybe e) a, c #) newtype ParserLevity e c (r :: RuntimeRep) (a :: TYPE r) = ParserLevity { getParserLevity :: forall s. c -> Maybe# (Leftovers# s) -> State# s -> (# State# s, Result# e c s r a #) } }}} Specifically, the function causing trouble is (as currently defined): {{{ {-# NOINLINE takeBytesUntilEndOfLineConsumeUnboxed #-} takeBytesUntilEndOfLineConsumeUnboxed :: ParserLevity e c BytesRep Bytes# takeBytesUntilEndOfLineConsumeUnboxed = ParserLevity (go (# (# #) | #)) where go :: Maybe# Bytes# -> c -> Maybe# (Leftovers# s) -> State# s -> (# State# s, Result# e c s BytesRep Bytes# #) go !_ c (# (# #) | #) s0 = (# s0, (# (# (# #) | #), (# Nothing | #), c #) #) go !mbytes c (# | (# bytes0@(# arr0, off0, len0 #), !stream0@(ByteStream streamFunc) #) #) s0 = case BAW.findAnyByte2 (I# off0) (I# len0) 10 13 (ByteArray arr0) of Nothing -> case streamFunc s0 of (# s1, r #) -> go (# | appendMaybeBytes mbytes bytes0 #) c r s1 Just (I# ix, W8# theByte) -> case theByte of 10## -> (# s0, (# (# | (# unsafeDrop# ((ix -# off0) +# 1# ) bytes0, stream0 #) #), (# | appendMaybeBytes mbytes (# arr0, off0, ix -# off0 #) #), c #) #) -- second case means it was 13 _ -> case ix <# (off0 +# len0 -# 1#) of 1# -> case indexWord8Array# arr0 (ix +# 1# ) of 10## -> (# s0, (# (# | (# unsafeDrop# ((ix -# off0) +# 2# ) bytes0, stream0 #) #), (# | appendMaybeBytes mbytes (# arr0, off0, ix -# off0 #) #), c #) #) _ -> (# s0, (# (# | (# unsafeDrop# (ix -# off0) bytes0, stream0 #) #), (# Nothing | #), c #) #) _ -> case nextNonEmpty stream0 s0 of (# s1, m #) -> case m of (# (# #) | #) -> (# s1, (# (# | (# unboxBytes (B.singleton 13), Stream.empty #) #), (# Nothing | #), c #) #) (# | (# bytes1@(# arr1, _, _ #), stream1 #) #) -> case indexWord8Array# arr1 0# of 10## -> (# s1, (# (# | (# unsafeDrop# 1# bytes1, stream1 #) #), (# | appendMaybeBytes mbytes (# arr0, off0, ix -# off0 #) #), c #) #) _ -> (# s1, (# (# | (# unboxBytes (B.cons 13 (boxBytes bytes1)), stream1 #) #), (# Nothing | #), c #) #) }}} That's all I've got for now. If no one's able to make headway, I'll probably come back to this and try to make a more minimal example at some point. I won't have time to do this soon though. -- Ticket URL: <http://ghc.haskell.org/trac/ghc/ticket/15300> GHC <http://www.haskell.org/ghc/> The Glasgow Haskell Compiler

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[GHC] #14398: Fail to install haskell platform on Windows
by GHC 24 Oct '18

24 Oct '18

#14398: Fail to install haskell platform on Windows -------------------------------------+------------------------------------- Reporter: KAAAsS | Owner: (none) Type: bug | Status: new Priority: normal | Milestone: Component: GHCi | Version: 8.2.1 Keywords: | Operating System: Windows Architecture: x86_64 | Type of failure: Installing GHC (amd64) | failed Test Case: | Blocked By: Blocking: | Related Tickets: Differential Rev(s): | Wiki Page: -------------------------------------+------------------------------------- I can't run WinGHCi after my installation. When I use command "ghci" in cmd, it returns: {{{ GHCi, version 8.2.1: http://www.haskell.org/ghc/ :? for help ghc.exe: internal error: mkPath failed converting char* to wchar_t* (GHC version 8.2.1 for x86_64_unknown_mingw32) Please report this as a GHC bug: http://www.haskell.org/ghc/reportabug This application has requested the Runtime to terminate it in an unusual way. Please contact the application's support team for more information. }}} I had tried to reinstall or download the Core(64-bit) version, but nothing changed. I think there's nothing wrong with my install precedure. Sorry for my poor English! BTW, my windows is under Chinese code system. I don't know whether this matters or not. -- Ticket URL: <http://ghc.haskell.org/trac/ghc/ticket/14398> GHC <http://www.haskell.org/ghc/> The Glasgow Haskell Compiler

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[GHC] #12677: Type equality in constraint not used?
by GHC 24 Oct '18

24 Oct '18

#12677: Type equality in constraint not used? -------------------------------------+------------------------------------- Reporter: Iceland_jack | Owner: Type: feature | Status: new request | Priority: normal | 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: -------------------------------------+------------------------------------- {{{#!hs data TyRep :: forall k. k -> Type where TyInt :: TyRep Int TyBool :: TyRep Bool TyMaybe :: TyRep Maybe TyApp :: TyRep f -> TyRep x -> TyRep (f x) }}} This is allowed: {{{#!hs zero :: TypeRep (a :: Type) -> a zero = undefined }}} but this is not {{{#!hs zero :: Type ~ k => TyRep (a :: k) -> a zero = undefined zero :: TyRep (a :: k) -> Type ~ k => a zero = undefined }}} {{{ tuHu.hs:20:35: error: … • Expected a type, but ‘a’ has kind ‘k’ • In the type signature: zero :: Type ~ k => R (a :: k) -> a Compilation failed. }}} -- Ticket URL: <http://ghc.haskell.org/trac/ghc/ticket/12677> GHC <http://www.haskell.org/ghc/> The Glasgow Haskell Compiler

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[GHC] #13087: AlternativeLayoutRule breaks LambdaCase
by GHC 24 Oct '18

24 Oct '18

#13087: AlternativeLayoutRule breaks LambdaCase -------------------------------------+------------------------------------- Reporter: ohhellojoe | Owner: Type: bug | Status: new Priority: normal | Milestone: Component: Compiler | Version: 8.0.1 (Parser) | 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: -------------------------------------+------------------------------------- {{{#!hs {-# LANGUAGE AlternativeLayoutRule #-} {-# LANGUAGE LambdaCase #-} isOne :: Int -> Bool isOne = \case 1 -> True _ -> False main = return () }}} {{{ $ ghc test-case [1 of 1] Compiling Main ( test-case.hs, test-case.o ) test-case.hs:5:15: error: parse error on input ‘1’ }}} It compiles fine without the AlternativeLayoutRule extension. -- Ticket URL: <http://ghc.haskell.org/trac/ghc/ticket/13087> GHC <http://www.haskell.org/ghc/> The Glasgow Haskell Compiler

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[GHC] #10453: \case should trigger auto-multiline mode in ghci
by GHC 24 Oct '18

24 Oct '18

#10453: \case should trigger auto-multiline mode in ghci -------------------------------------+------------------------------------- Reporter: dmwit | Owner: Type: feature | Status: new request | Milestone: Priority: normal | Version: 7.10.1 Component: Compiler | Operating System: Unknown/Multiple Keywords: | Type of failure: None/Unknown Architecture: | Blocked By: Unknown/Multiple | Related Tickets: Test Case: | Blocking: | Differential Revisions: | -------------------------------------+------------------------------------- In ghci, most block heralds trigger the multiline mode when :set +m is on. However, \case does not (and should). Compare: {{{ Prelude> ($True) (\case Prelude| x -> x Prelude| ) True Prelude> ($True) $ \case <interactive>:11:11: Empty list of alternatives in case expression Use EmptyCase to allow this }}} -- Ticket URL: <http://ghc.haskell.org/trac/ghc/ticket/10453> GHC <http://www.haskell.org/ghc/> The Glasgow Haskell Compiler

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[GHC] #12119: Can't create injective type family equation with TypeError as the RHS
by GHC 23 Oct '18

23 Oct '18

#12119: Can't create injective type family equation with TypeError as the RHS -------------------------------------+------------------------------------- Reporter: RyanGlScott | Owner: Type: feature | Status: new request | Priority: normal | Milestone: Component: Compiler | Version: 8.0.1 (Type checker) | Keywords: | Operating System: Unknown/Multiple CustomTypeErrors, TypeFamilies, | Injective | Architecture: | Type of failure: None/Unknown Unknown/Multiple | Test Case: | Blocked By: Blocking: | Related Tickets: Differential Rev(s): | Wiki Page: -------------------------------------+------------------------------------- For the longest time, I've wanted to make a type family like this injective: {{{#!hs type family Foo (a :: *) :: * where Foo Bar = Int Foo Baz = Char }}} But the problem is that `Foo` is defined on //all// types of kind `*`, so the above definition is inherently non-injective. With the introduction of `TypeError`s, however, I thought I could rule out all other cases: {{{#!hs import GHC.TypeLits type family Foo (a :: *) = (r :: *) | r -> a where Foo Bar = Int Foo Baz = Char Foo _ = TypeError ('Text "boom") }}} But this doesn't work, sadly: {{{ Injective.hs:18:3: error: • Type family equations violate injectivity annotation: Foo Bar = Int -- Defined at Injective.hs:18:3 Foo _ = (TypeError ...) -- Defined at Injective.hs:20:3 • In the equations for closed type family ‘Foo’ In the type family declaration for ‘Foo’ Injective.hs:20:3: error: • Type family equation violates injectivity annotation. Type variable ‘_’ cannot be inferred from the right-hand side. In the type family equation: Foo _ = (TypeError ...) -- Defined at Injective.hs:20:3 • In the equations for closed type family ‘Foo’ In the type family declaration for ‘Foo’ Injective.hs:20:3: error: • Type family equation violates injectivity annotation. RHS of injective type family equation cannot be a type family: Foo _ = (TypeError ...) -- Defined at Injective.hs:20:3 • In the equations for closed type family ‘Foo’ In the type family declaration for ‘Foo’ }}} From GHC's perspective, `TypeError` is just another type family, so it thinks it violates injectivity. But should this be the case? After all, having the RHS of a type family equation being `TypeError` is, in my perspective, tantamount to making that type family undefined for those inputs. It seems like if we successfully conclude that `Foo a ~ Foo b` (and GHC hasn't blown up yet due to type erroring), we should be able to conclude that `a ~ b`. Could this be accomplished by simply adding a special case for `TypeError` in the injectivity checker? -- Ticket URL: <http://ghc.haskell.org/trac/ghc/ticket/12119> GHC <http://www.haskell.org/ghc/> The Glasgow Haskell Compiler

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[GHC] #14062: Pure syntax transformation affects performance.
by GHC 23 Oct '18

23 Oct '18

#14062: Pure syntax transformation affects performance. -------------------------------------+------------------------------------- Reporter: danilo2 | Owner: (none) Type: bug | Status: new Priority: high | 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: -------------------------------------+------------------------------------- Hi! Let's consider the following code (compiled with `-O2`, `mtl` and `criterion` needed): {{{#!hs module Main where import Prelude as import Criterion.Main import Control.Monad.State.Strict import Control.Monad.Identity repeatM :: Monad m => m a -> Int -> m () repeatM f = go where go 0 = pure () go i = f >> go (i - 1) {-# INLINE repeatM #-} incState :: MonadState Int m => m () incState = modify' (1+) ; {-# INLINE incState #-} test1, test2 :: Int -> Int test1 = \n -> (runIdentity . flip evalStateT 0 . (\a -> repeatM incState a >> S.get)) n ; {-# INLINE test1 #-} test2 = \n -> runIdentity . flip evalStateT 0 $ repeatM incState n >> get ; {-# INLINE test2 #-} main :: IO () main = do defaultMain [ bgroup "monad transformers overhead" [ bench "test1" $ nf test1 100000000 , bench "test2" $ nf test2 100000000 ] ] }}} Functions `test1` and `test2` differ only syntactically and this difference should not affect GHC's inliner, because their implementations use fully saturated calls. The generated core for `test1` and `test2` is practically identical (there is an additional alias created for `test1`: `test1 = lvl1_rhor 'cast' ...`). The problem is that `test1` runs **3 times faster** than `test2`. As a side note - if we add more state transformers to `test1`, it optimizes them all away, while `test2` runs slower with each new transformer applied. -- Ticket URL: <http://ghc.haskell.org/trac/ghc/ticket/14062> GHC <http://www.haskell.org/ghc/> The Glasgow Haskell Compiler

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[GHC] #14980: Runtime performance regression with binary operations on vectors
by GHC 23 Oct '18

23 Oct '18

#14980: Runtime performance regression with binary operations on vectors -------------------------------------+------------------------------------- Reporter: ttylec | Owner: (none) Type: bug | Status: new Priority: normal | Milestone: Component: Compiler | Version: 8.2.2 Keywords: vector | Operating System: Unknown/Multiple bitwise operations | Architecture: | Type of failure: Runtime Unknown/Multiple | performance bug Test Case: | Blocked By: Blocking: | Related Tickets: Differential Rev(s): | Wiki Page: -------------------------------------+------------------------------------- Let me briefly explain our use case: we have a machine learning tools created in Haskell. Basically it builds association rules for a database. In plain English: predicates on data rows. We need to score them, so we need to check how many rows are "matched" by the predicate. In order to optimize performance, our code uses two main representations for data: one is a "human readable", where a values are real values. The second one is binarized representation for categorical data. The latter has is actually a family of representation, since we pack bits into tuples of Word64 and use bitwise operation to implement logic. Simplified but representative code is attached. In GHC 8.0.2 binary representation is faster by one order of magnitude than the "human readable" one: {{{ ➜ ghc-bug stack exec performance-bug-pair-1 "Generated" benchmarking 256 columns/raw unbox vectors time 342.6 μs (338.3 μs .. 348.0 μs) 0.999 R² (0.998 R² .. 1.000 R²) mean 339.3 μs (337.5 μs .. 342.0 μs) std dev 7.203 μs (5.596 μs .. 10.07 μs) variance introduced by outliers: 13% (moderately inflated) benchmarking 256 columns/binary packed time 32.07 μs (29.69 μs .. 34.14 μs) 0.982 R² (0.976 R² .. 0.997 R²) mean 29.97 μs (29.41 μs .. 31.03 μs) std dev 2.428 μs (1.526 μs .. 3.750 μs) variance introduced by outliers: 78% (severely inflated) }}} In GHC 8.2.2 (and later) binary representation performance is similar to "human readable", so no performance gain: {{{ ➜ ghc-bug stack exec performance-bug-pair-1 "Generated" benchmarking 256 columns/raw unbox vectors time 442.4 μs (406.7 μs .. 474.5 μs) 0.978 R² (0.969 R² .. 0.993 R²) mean 399.3 μs (391.3 μs .. 415.1 μs) std dev 34.73 μs (20.36 μs .. 53.29 μs) variance introduced by outliers: 71% (severely inflated) benchmarking 256 columns/binary packed time 378.6 μs (295.8 μs .. 488.0 μs) 0.637 R² (0.492 R² .. 0.780 R²) mean 568.1 μs (437.1 μs .. 747.6 μs) std dev 308.7 μs (233.6 μs .. 386.1 μs) variance introduced by outliers: 98% (severely inflated) }}} However, for certain compilation paths, we still can get similar speedup as with GHC 8.0.2. In the above examples we used 4-tuple of Word64 as binary representation. In the following code we run two tests: one on just Word64 and one of 4-tuple of Word64. The difference is that we just add the Word64 case: {{{ ➜ ghc-bug stack exec performance-bug-pair-2 "Generated" benchmarking 64 columns/raw unbox vectors time 337.6 μs (336.1 μs .. 339.3 μs) 0.999 R² (0.998 R² .. 1.000 R²) mean 349.6 μs (344.4 μs .. 359.7 μs) std dev 23.22 μs (15.39 μs .. 38.22 μs) variance introduced by outliers: 60% (severely inflated) benchmarking 64 columns/binary packed time 21.66 μs (21.53 μs .. 21.79 μs) 1.000 R² (0.999 R² .. 1.000 R²) mean 21.68 μs (21.53 μs .. 21.89 μs) std dev 613.2 ns (466.0 ns .. 806.0 ns) variance introduced by outliers: 30% (moderately inflated) benchmarking 256 columns/raw unbox vectors time 344.5 μs (341.6 μs .. 348.2 μs) 0.999 R² (0.999 R² .. 1.000 R²) mean 345.1 μs (342.5 μs .. 349.3 μs) std dev 10.66 μs (7.997 μs .. 16.34 μs) variance introduced by outliers: 25% (moderately inflated) benchmarking 256 columns/binary packed time 28.04 μs (27.70 μs .. 28.46 μs) 0.999 R² (0.999 R² .. 1.000 R²) mean 28.05 μs (27.85 μs .. 28.30 μs) std dev 758.2 ns (628.2 ns .. 907.6 ns) variance introduced by outliers: 27% (moderately inflated) }}} I made a variant of code with simpler accumulating function (in our code we accumulate pair of integers, simplified accumulator work on one integer). GHC 8.2.2 in that case losses speed-up with 4-tuples: {{{ ➜ ghc-bug stack exec performance-bug-2 "Generated" benchmarking 64 columns/raw unbox vectors time 333.8 μs (333.0 μs .. 335.1 μs) 1.000 R² (0.999 R² .. 1.000 R²) mean 333.6 μs (332.4 μs .. 335.8 μs) std dev 5.651 μs (3.233 μs .. 9.582 μs) benchmarking 64 columns/binary packed time 39.06 μs (38.98 μs .. 39.14 μs) 1.000 R² (1.000 R² .. 1.000 R²) mean 38.94 μs (38.83 μs .. 39.14 μs) std dev 495.0 ns (310.2 ns .. 782.1 ns) benchmarking 256 columns/raw unbox vectors time 336.9 μs (336.2 μs .. 337.9 μs) 1.000 R² (1.000 R² .. 1.000 R²) mean 337.5 μs (336.2 μs .. 339.8 μs) std dev 5.757 μs (2.946 μs .. 8.979 μs) benchmarking 256 columns/binary packed time 239.8 μs (237.6 μs .. 243.0 μs) 0.998 R² (0.996 R² .. 0.999 R²) mean 251.4 μs (247.9 μs .. 259.8 μs) std dev 11.50 μs (5.662 μs .. 19.79 μs) variance introduced by outliers: 37% (moderately inflated) }}} In GHC 8.0.2 we have speed-up in both cases. What may be related: using random-fu to generate random numbers seems to produce broken code on GHC 8.2.2 (the `performance-bug-rfu.hs` source). Short description of attached sources: - performance-bug-pair-2.hs: using two binary representations - performance-bug-pair-1.hs: using one binary representation (one case commented) - performance-bug-1.hs: using one binary representation with simplified accumulator - performance-bug-2.hs: using two binary representation with simplified accumulator - performance-bug-rfu.hs: using random-fu to generate data (optional) - stack-8.0.yaml: stack file for GHC-8.0.2 - stack-8.2.yaml: stack file for GHC-8.2.2 - stack-nightly.yaml: stack file for GHC-8.4 - performance-bug.cabal: to be able to stack build everything. -- Ticket URL: <http://ghc.haskell.org/trac/ghc/ticket/14980> GHC <http://www.haskell.org/ghc/> The Glasgow Haskell Compiler

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[GHC] #15201: GHC 8.4 fails to build on Debian s390x
by GHC 22 Oct '18

22 Oct '18

#15201: GHC 8.4 fails to build on Debian s390x --------------------------------+------------------------------------- Reporter: clint | Owner: (none) Type: bug | Status: new Priority: normal | Milestone: 8.6.1 Component: Compiler | Version: 8.4.3 Keywords: | Operating System: Unknown/Multiple Architecture: Other | Type of failure: None/Unknown Test Case: | Blocked By: Blocking: | Related Tickets: Differential Rev(s): | Wiki Page: --------------------------------+------------------------------------- {{{ "/usr/bin/ghc" -hisuf hi -osuf o -hcsuf hc -static -H32m -O -lffi -optl-pthread -Wall -Iincludes -Iincludes/dist -Iincludes/dist- derivedconstants/header -Iincludes/dist-ghcconstants/header -package-db libraries/bootstrapping.conf -this-unit-id ghc-8.4.3 -hide-all-packages -i -icompiler/backpack -icompiler/basicTypes -icompiler/cmm -icompiler/codeGen -icompiler/coreSyn -icompiler/deSugar -icompiler/ghci -icompiler/hsSyn -icompiler/iface -icompiler/llvmGen -icompiler/main -icompiler/nativeGen -icompiler/parser -icompiler/prelude -icompiler/profiling -icompiler/rename -icompiler/simplCore -icompiler/simplStg -icompiler/specialise -icompiler/stgSyn -icompiler/stranal -icompiler/typecheck -icompiler/types -icompiler/utils -icompiler/vectorise -icompiler/stage1/build -Icompiler/stage1/build -icompiler/stage1/build/./autogen -Icompiler/stage1/build/./autogen -Icompiler/. -Icompiler/parser -Icompiler/utils -Icompiler/stage1 -Icompiler/stage1/build/. -Icompiler/stage1/build/parser -Icompiler/stage1/build/utils -Icompiler/stage1/build/stage1 -optP- include -optPcompiler/stage1/build/./autogen/cabal_macros.h -package-id base-4.10.1.0 -package-id deepseq-1.4.3.0 -package-id directory-1.3.0.2 -package-id process-1.6.1.0 -package-id bytestring-0.10.8.2 -package-id binary-0.8.5.1 -package-id time-1.8.0.2 -package-id containers-0.5.10.2 -package-id array-0.5.2.0 -package-id filepath-1.4.1.2 -package-id template-haskell-2.13.0.0 -package-id hpc-0.6.0.3 -package-id transformers-0.5.5.0 -package-id ghc-boot-8.4.3 -package-id ghc-boot- th-8.4.3 -package-id ghci-8.4.3 -package-id unix-2.7.2.2 -package-id terminfo-0.4.1.1 -Wall -Wno-name-shadowing -Wnoncanonical-monad-instances -Wnoncanonical-monadfail-instances -Wnoncanonical-monoid-instances -this- unit-id ghc -XHaskell2010 -XNoImplicitPrelude -DNO_REGS -DNOSMP -optc- DNOSMP -DSTAGE=1 -Rghc-timing -Wcpp-undef -no-user-package-db -rtsopts -odir compiler/stage1/build -hidir compiler/stage1/build -stubdir compiler/stage1/build -c compiler/utils/GhcPrelude.hs -o compiler/stage1/build/GhcPrelude.o /tmp/ghcf6ae_0/ghc_3.hc:7:1: error: warning: data definition has no type or storage class EI_(ghczmprim_GHCziTypes_TrNameS_con_info); ^~~ | 7 | EI_(ghczmprim_GHCziTypes_TrNameS_con_info); | ^ /tmp/ghcf6ae_0/ghc_3.hc:7:1: error: warning: type defaults to 'int' in declaration of 'EI_' [-Wimplicit- int] | 7 | EI_(ghczmprim_GHCziTypes_TrNameS_con_info); | ^ /tmp/ghcf6ae_0/ghc_3.hc:7:1: error: warning: parameter names (without types) in function declaration | 7 | EI_(ghczmprim_GHCziTypes_TrNameS_con_info); | ^ In file included from /tmp/ghcf6ae_0/ghc_3.hc:3:0: error: /tmp/ghcf6ae_0/ghc_3.hc:8:5: error: error: conflicting types for 'ghc_GhcPrelude_zdtrModule4_bytes' EB_(ghc_GhcPrelude_zdtrModule4_bytes); ^ | 8 | EB_(ghc_GhcPrelude_zdtrModule4_bytes); | ^ includes/Stg.h:236:37: error: note: in definition of macro 'EB_' #define EB_(X) extern const char X[] ^ | 236 | #define EB_(X) extern const char X[] | ^ /tmp/ghcf6ae_0/ghc_3.hc:6:6: error: note: previous definition of 'ghc_GhcPrelude_zdtrModule4_bytes' was here char ghc_GhcPrelude_zdtrModule4_bytes[] = "ghc"; ^~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~ | 6 | char ghc_GhcPrelude_zdtrModule4_bytes[] = "ghc"; | ^ /tmp/ghcf6ae_0/ghc_3.hc:10:6: error: error: 'ghczmprim_GHCziTypes_TrNameS_con_info' undeclared here (not in a function) (W_)&ghczmprim_GHCziTypes_TrNameS_con_info, (W_)&ghc_GhcPrelude_zdtrModule4_bytes ^~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~ | 10 | (W_)&ghczmprim_GHCziTypes_TrNameS_con_info, (W_)&ghc_GhcPrelude_zdtrModule4_bytes | ^ /tmp/ghcf6ae_0/ghc_3.hc:13:1: error: warning: data definition has no type or storage class EI_(ghczmprim_GHCziTypes_TrNameS_con_info); ^~~ | 13 | EI_(ghczmprim_GHCziTypes_TrNameS_con_info); | ^ /tmp/ghcf6ae_0/ghc_3.hc:13:1: error: warning: type defaults to 'int' in declaration of 'EI_' [-Wimplicit- int] | 13 | EI_(ghczmprim_GHCziTypes_TrNameS_con_info); | ^ /tmp/ghcf6ae_0/ghc_3.hc:13:1: error: warning: parameter names (without types) in function declaration | 13 | EI_(ghczmprim_GHCziTypes_TrNameS_con_info); | ^ In file included from /tmp/ghcf6ae_0/ghc_3.hc:3:0: error: /tmp/ghcf6ae_0/ghc_3.hc:14:5: error: error: conflicting types for 'ghc_GhcPrelude_zdtrModule2_bytes' EB_(ghc_GhcPrelude_zdtrModule2_bytes); ^ | 14 | EB_(ghc_GhcPrelude_zdtrModule2_bytes); | ^ includes/Stg.h:236:37: error: note: in definition of macro 'EB_' #define EB_(X) extern const char X[] ^ | 236 | #define EB_(X) extern const char X[] | ^ /tmp/ghcf6ae_0/ghc_3.hc:12:6: error: note: previous definition of 'ghc_GhcPrelude_zdtrModule2_bytes' was here char ghc_GhcPrelude_zdtrModule2_bytes[] = "GhcPrelude"; ^~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~ | 12 | char ghc_GhcPrelude_zdtrModule2_bytes[] = "GhcPrelude"; | ^ /tmp/ghcf6ae_0/ghc_3.hc:16:1: error: error: initializer element is not constant (W_)&ghczmprim_GHCziTypes_TrNameS_con_info, (W_)&ghc_GhcPrelude_zdtrModule2_bytes ^ | 16 | (W_)&ghczmprim_GHCziTypes_TrNameS_con_info, (W_)&ghc_GhcPrelude_zdtrModule2_bytes | ^ /tmp/ghcf6ae_0/ghc_3.hc:16:1: error: note: (near initialization for 'ghc_GhcPrelude_zdtrModule1_closure[0]') | 16 | (W_)&ghczmprim_GHCziTypes_TrNameS_con_info, (W_)&ghc_GhcPrelude_zdtrModule2_bytes | ^ /tmp/ghcf6ae_0/ghc_3.hc:18:1: error: warning: data definition has no type or storage class EI_(ghczmprim_GHCziTypes_Module_con_info); ^~~ | 18 | EI_(ghczmprim_GHCziTypes_Module_con_info); | ^ /tmp/ghcf6ae_0/ghc_3.hc:18:1: error: warning: type defaults to 'int' in declaration of 'EI_' [-Wimplicit- int] | 18 | EI_(ghczmprim_GHCziTypes_Module_con_info); | ^ /tmp/ghcf6ae_0/ghc_3.hc:18:1: error: warning: parameter names (without types) in function declaration | 18 | EI_(ghczmprim_GHCziTypes_Module_con_info); | ^ /tmp/ghcf6ae_0/ghc_3.hc:19:1: error: warning: data definition has no type or storage class EI_(ghc_GhcPrelude_zdtrModule1_closure); ^~~ | 19 | EI_(ghc_GhcPrelude_zdtrModule1_closure); | ^ /tmp/ghcf6ae_0/ghc_3.hc:19:1: error: warning: type defaults to 'int' in declaration of 'EI_' [-Wimplicit- int] | 19 | EI_(ghc_GhcPrelude_zdtrModule1_closure); | ^ /tmp/ghcf6ae_0/ghc_3.hc:19:1: error: warning: parameter names (without types) in function declaration | 19 | EI_(ghc_GhcPrelude_zdtrModule1_closure); | ^ /tmp/ghcf6ae_0/ghc_3.hc:20:1: error: warning: data definition has no type or storage class EI_(ghc_GhcPrelude_zdtrModule3_closure); ^~~ | 20 | EI_(ghc_GhcPrelude_zdtrModule3_closure); | ^ /tmp/ghcf6ae_0/ghc_3.hc:20:1: error: warning: type defaults to 'int' in declaration of 'EI_' [-Wimplicit- int] | 20 | EI_(ghc_GhcPrelude_zdtrModule3_closure); | ^ /tmp/ghcf6ae_0/ghc_3.hc:20:1: error: warning: parameter names (without types) in function declaration | 20 | EI_(ghc_GhcPrelude_zdtrModule3_closure); | ^ /tmp/ghcf6ae_0/ghc_3.hc:22:6: error: error: 'ghczmprim_GHCziTypes_Module_con_info' undeclared here (not in a function); did you mean 'ghczmprim_GHCziTypes_TrNameS_con_info'? (W_)&ghczmprim_GHCziTypes_Module_con_info, ((W_)&ghc_GhcPrelude_zdtrModule3_closure+1), ((W_)&ghc_GhcPrelude_zdtrModule1_closure+1), 0x3UL ^~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~ ghczmprim_GHCziTypes_TrNameS_con_info | 22 | (W_)&ghczmprim_GHCziTypes_Module_con_info, ((W_)&ghc_GhcPrelude_zdtrModule3_closure+1), ((W_)&ghc_GhcPrelude_zdtrModule1_closure+1), 0x3UL | ^ /tmp/ghcf6ae_0/ghc_3.hc:22:1: error: error: initializer element is not constant (W_)&ghczmprim_GHCziTypes_Module_con_info, ((W_)&ghc_GhcPrelude_zdtrModule3_closure+1), ((W_)&ghc_GhcPrelude_zdtrModule1_closure+1), 0x3UL ^ | 22 | (W_)&ghczmprim_GHCziTypes_Module_con_info, ((W_)&ghc_GhcPrelude_zdtrModule3_closure+1), ((W_)&ghc_GhcPrelude_zdtrModule1_closure+1), 0x3UL | ^ /tmp/ghcf6ae_0/ghc_3.hc:22:1: error: note: (near initialization for 'ghc_GhcPrelude_zdtrModule_closure[0]') | 22 | (W_)&ghczmprim_GHCziTypes_Module_con_info, ((W_)&ghc_GhcPrelude_zdtrModule3_closure+1), ((W_)&ghc_GhcPrelude_zdtrModule1_closure+1), 0x3UL | ^ `gcc' failed in phase `C Compiler'. (Exit code: 1) }}} https://buildd.debian.org/status/fetch.php?pkg=ghc&arch=s390x&ver=8.4.3-1&s… -- Ticket URL: <http://ghc.haskell.org/trac/ghc/ticket/15201> GHC <http://www.haskell.org/ghc/> The Glasgow Haskell Compiler

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