August 2015 - ghc-tickets

Re: [GHC] #7944: GHC goes into an apparently infinite loop at -O2
by GHC 02 Aug '15

02 Aug '15

#7944: GHC goes into an apparently infinite loop at -O2 -------------------------------------+------------------------------------- Reporter: bos | Owner: Type: bug | Status: new Priority: normal | Milestone: Component: Compiler | Version: 7.9 Resolution: | Keywords: Operating System: Unknown/Multiple | Architecture: x86_64 Type of failure: Compile-time | (amd64) crash | Test Case: Blocked By: | Blocking: Related Tickets: #5550 #8852 | Differential Revisions: -------------------------------------+------------------------------------- Comment (by thomie): Yes, infinite loop with ghc-7.10.2 as well as ghc-7.11.20150711 (HEAD). -- Ticket URL: <http://ghc.haskell.org/trac/ghc/ticket/7944#comment:9> GHC <http://www.haskell.org/ghc/> The Glasgow Haskell Compiler

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Re: [GHC] #7944: GHC goes into an apparently infinite loop at -O2
by GHC 02 Aug '15

02 Aug '15

#7944: GHC goes into an apparently infinite loop at -O2 -------------------------------------+------------------------------------- Reporter: bos | Owner: Type: bug | Status: new Priority: normal | Milestone: Component: Compiler | Version: 7.9 Resolution: | Keywords: Operating System: Unknown/Multiple | Architecture: x86_64 Type of failure: Compile-time | (amd64) crash | Test Case: Blocked By: | Blocking: Related Tickets: #5550 #8852 | Differential Revisions: -------------------------------------+------------------------------------- Comment (by amosrobinson): Hi, I had a go reducing this more. I only have ghc 7.8.3, so would someone be able to try this on head? {{{ #!haskell module T7944 where import GHC.Exts -- Force specialisation of "go" data SPEC = SPEC | SPEC2 {-# ANN type SPEC ForceSpecConstr #-} -- This is more or less just an ordinary fold go :: SPEC -> [a] -> IntMap a -> IntMap a go SPEC [] m = m go SPEC (_:xs) m = go SPEC xs -- This would be the "worker function" of the fold $ Unary m -- Both constructors are necessary, despite only one being used data IntMap a = Nil | Unary (IntMap a) }}} -- Ticket URL: <http://ghc.haskell.org/trac/ghc/ticket/7944#comment:8> GHC <http://www.haskell.org/ghc/> The Glasgow Haskell Compiler

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Re: [GHC] #7944: GHC goes into an apparently infinite loop at -O2
by GHC 02 Aug '15

02 Aug '15

#7944: GHC goes into an apparently infinite loop at -O2 -------------------------------------+------------------------------------- Reporter: bos | Owner: Type: bug | Status: new Priority: normal | Milestone: Component: Compiler | Version: 7.9 Resolution: | Keywords: Operating System: Unknown/Multiple | Architecture: x86_64 Type of failure: Compile-time | (amd64) crash | Test Case: Blocked By: | Blocking: Related Tickets: #5550 #8852 | Differential Revisions: -------------------------------------+------------------------------------- Comment (by thomie): `-fno-spec-constr` indeed fixes the problem. I reduced the test code some more, but it still requires `vector`. {{{ $ cabal install vector # cabal gave me vector-0.10.12.3 $ ghc-7.10.2 -O2 --make Repro.hs # also fails with ghc-7.11.20150711 }}} {{{#!haskell module Repro where import qualified Data.Vector as V import qualified IntMap as I constructMap :: V.Vector (Int, [Int]) -> I.IntMap [Int] constructMap = V.foldl' go I.empty where go m (k,v) = snd $ I.insertWith (++) k v m }}} {{{#!haskell module IntMap where import Data.Bits ((.&.), complement, xor) import GHC.Num (Num(..)) import GHC.Real (fromIntegral) type Nat = Word natFromInt :: Key -> Nat natFromInt i = fromIntegral i intFromNat :: Nat -> Key intFromNat w = fromIntegral w data IntMap a = Nil | Tip Key a | Bin Prefix Mask (IntMap a) (IntMap a) type Prefix = Int type Mask = Int type Key = Int empty :: IntMap a empty = Nil insertWith :: (a -> a -> a) -> Key -> a -> IntMap a -> (Maybe a, IntMap a) insertWith f k x t = case t of Bin p m l r | nomatch k p m -> (Nothing, join k (Tip k x) p t) | zero k m -> let (found, l') = insertWith f k x l in (found, Bin p m l' r) | otherwise -> let (found, r') = insertWith f k x r in (found, Bin p m l r') Tip ky y | k == ky -> (Just y, Tip k (f x y)) | otherwise -> (Nothing, join k (Tip k x) ky t) Nil -> (Nothing, Tip k x) join :: Prefix -> IntMap a -> Prefix -> IntMap a -> IntMap a join p1 t1 p2 t2 | zero p1 m = Bin p m t1 t2 | otherwise = Bin p m t2 t1 where m = branchMask p1 p2 p = mask p1 m zero :: Key -> Mask -> Bool zero i m = (natFromInt i) .&. (natFromInt m) == 0 nomatch :: Key -> Prefix -> Mask -> Bool nomatch i p m = (mask i m) /= p mask :: Key -> Mask -> Prefix mask i m = maskW (natFromInt i) (natFromInt m) maskW :: Nat -> Nat -> Prefix maskW i m = intFromNat (i .&. (complement (m-1) `xor` m)) branchMask :: Prefix -> Prefix -> Mask branchMask p1 p2 = intFromNat (highestBitMask (natFromInt p1)) highestBitMask :: Nat -> Nat highestBitMask x1 = x1 }}} -- Ticket URL: <http://ghc.haskell.org/trac/ghc/ticket/7944#comment:7> GHC <http://www.haskell.org/ghc/> The Glasgow Haskell Compiler

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[GHC] #10727: compiler/rename/RnSource.lhs:429:14-81: Irrefutable pattern failed
by GHC 02 Aug '15

02 Aug '15

#10727: compiler/rename/RnSource.lhs:429:14-81: Irrefutable pattern failed -------------------------------------+------------------------------------- Reporter: doelie | Owner: Type: bug | Status: new Priority: normal | Milestone: Component: Compiler | Version: 7.4.1 Keywords: | Operating System: Linux Architecture: | Type of failure: None/Unknown Unknown/Multiple | Test Case: | Blocked By: Blocking: | Related Tickets: Differential Revisions: | -------------------------------------+------------------------------------- see bug.sh in: http://zwizwa.be/stuff/ghc_bug.tgz make: Entering directory `/home/tom/pub/darcs/meta/siso' ghc Test.hs [ 9 of 10] Compiling Code ( Code.hs, Code.o ) ghc: panic! (the 'impossible' happened) (GHC version 7.4.1 for x86_64-unknown-linux): compiler/rename/RnSource.lhs:429:14-81: Irrefutable pattern failed for pattern Data.Maybe.Just (inst_tyvars, _, SrcLoc.L _ cls, _) Please report this as a GHC bug: http://www.haskell.org/ghc/reportabug -- Ticket URL: <http://ghc.haskell.org/trac/ghc/ticket/10727> GHC <http://www.haskell.org/ghc/> The Glasgow Haskell Compiler

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Re: [GHC] #7521: Accelerate examples does not compile with default value of -fsimpl-tick-factor
by GHC 02 Aug '15

02 Aug '15

#7521: Accelerate examples does not compile with default value of -fsimpl-tick- factor -------------------------------------+------------------------------------- Reporter: eamsden | Owner: Type: bug | Status: new Priority: normal | Milestone: 7.12.1 Component: Compiler | Version: 7.6.1 Resolution: | Keywords: Operating System: Unknown/Multiple | Architecture: Type of failure: Compile-time | Unknown/Multiple crash | Test Case: Blocked By: | Blocking: Related Tickets: | Differential Revisions: -------------------------------------+------------------------------------- Changes (by bgamari): * priority: high => normal Comment: I'm not even convinced this should be considered to be a bug. Various programs require varying amounts of effort from the simplifier; it is fair to say that `accelerate` sits on the high end of this spectrum. Do we really want to set the default simplifier tick factor to accommodate this extreme case? For the moment I'm going to lower the priority of this ticket, although arguably we could just close it. -- Ticket URL: <http://ghc.haskell.org/trac/ghc/ticket/7521#comment:15> GHC <http://www.haskell.org/ghc/> The Glasgow Haskell Compiler

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[GHC] #10705: make configure warn when ghc-tarballs is missing on windows and provide guidance to download it.
by GHC 02 Aug '15

02 Aug '15

#10705: make configure warn when ghc-tarballs is missing on windows and provide guidance to download it. -------------------------------------+------------------------------------- Reporter: Phyx- | Owner: Phyx- Type: task | Status: new Priority: normal | Milestone: 7.12.1 Component: Build | Version: 7.11 System | Keywords: | Operating System: Windows Architecture: | Type of failure: None/Unknown Unknown/Multiple | Test Case: | Blocked By: Blocking: | Related Tickets: #9218 Differential Revisions: | -------------------------------------+------------------------------------- Currently checking out the source on windows requires two git checkouts. One for the GHC sources and one for the GHC-tarballs. This patch will make configure issue an error if compiling under windows and the GHC-tarballs folder is missing. On failure the user is told which command they need to run to get the tarballs or if they want configure to handle it for them configure provide the `--enable-tarballs-autodownload` flag. This is one part of the bigger #9218 patch which is being flit up to get it through. -- Ticket URL: <http://ghc.haskell.org/trac/ghc/ticket/10705> GHC <http://www.haskell.org/ghc/> The Glasgow Haskell Compiler

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[GHC] #9234: Compiled code performance regression
by GHC 02 Aug '15

02 Aug '15

#9234: Compiled code performance regression ------------------------------------+--------------------------------- Reporter: augustss | Owner: Type: bug | Status: new Priority: low | Milestone: Component: Compiler | Version: 7.8.2 Keywords: | Operating System: Windows Architecture: Unknown/Multiple | Type of failure: None/Unknown Difficulty: Unknown | Test Case: Blocked By: | Blocking: Related Tickets: | ------------------------------------+--------------------------------- Upgrading from ghc 7.2 to 7.8 has slowed down our main application noticeably. This is with 32-bit Windows. Here's some 7.2 numbers: {{{ INIT time 0.00s ( 0.00s elapsed) MUT time 287.78s (290.41s elapsed) GC time 87.39s ( 88.43s elapsed) EXIT time 0.00s ( 0.00s elapsed) Total time 375.63s (378.86s elapsed) }}} And corresponding 7.8 numbers: {{{ INIT time 0.00s ( 0.00s elapsed) MUT time 298.34s (301.35s elapsed) GC time 88.16s ( 89.27s elapsed) EXIT time 0.00s ( 0.00s elapsed) Total time 386.93s (390.62s elapsed) }}} This is not unexpected since every ghc upgrade so far has slowed down out code; it's just following the trend we expect. -- Ticket URL: <http://ghc.haskell.org/trac/ghc/ticket/9234> GHC <http://www.haskell.org/ghc/> The Glasgow Haskell Compiler

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[GHC] #10159: cabal build/ghc compiler causes sudden hard reboot of my computer!
by GHC 02 Aug '15

02 Aug '15

#10159: cabal build/ghc compiler causes sudden hard reboot of my computer! -----------------------------------------+--------------------------------- Reporter: jamshid | Owner: Type: bug | Status: new Priority: normal | Milestone: Component: Compiler | Version: 7.8.4 Keywords: | Operating System: Linux Architecture: x86_64 (amd64) | Type of failure: None/Unknown Test Case: | Blocked By: Blocking: | Related Tickets: Differential Revisions: | -----------------------------------------+--------------------------------- I know this sounds pretty nuts, but compiling using ghc, via "cabal build" often suddenly reboots my computer (not the slow "please save your settings" type, but the sudden harsh sound of a relay click and immediate blackness followed by the BIOS screen). This happens somewhat randomly, although the probability of it occurring definitely goes up with a larger codebase. Beyond a certain size, it is pretty much guaranteed to happen. This could possibly have something to do with faulty hardware.... but I am not so sure because.... 1. The reboot only occurs when compiling with GHC. Nothing else (movie watching, compiling with gcc, processing audio, etc) causes this to happen. Furthermore the reboot is as likely to happen on a computer with no other program running as one with tons of background stuff, the ghc build is the only factor. Other than this bug, it is a powerful and reliable machine. 2. The reboot only occurs when I type "cabal build", not "cabal install", even if the project has just been cleaned. If it were just an overheating microprocessor, I would expect the problem to exist in both cases. In fact, as long as I don't type in "cabal build" exactly, I can download large projects (like the ghc compiler source code itself) and build them without a problem. I am even at a loss of what info to give you. I would be happy to supply whatever info you request and even do some debugging. For starters, here is my configuration.... Ubuntu 14.10 Kernel version 3.16.0-31-generic ghc version 7.8.4 cabal-install version 1.22.0.1 using version 1.22.1.1 of the Cabal library CPU- Intel(R) Core(TM) i7-4770 CPU @ 3.40GHz 16GB RAM Motherboard Gigabyte GA-Z87-D3HP I am not sure if logs will be of any use, because I am pretty sure that the sudden nature of the reboot prevents any info from being output.... -- Ticket URL: <http://ghc.haskell.org/trac/ghc/ticket/10159> GHC <http://www.haskell.org/ghc/> The Glasgow Haskell Compiler

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Re: [GHC] #1600: Optimisation: CPR the results of IO
by GHC 02 Aug '15

02 Aug '15

#1600: Optimisation: CPR the results of IO -------------------------------------+------------------------------------- Reporter: simonmar | Owner: Type: task | Status: new Priority: lowest | Milestone: 7.12.1 Component: Compiler | Version: 6.6.1 Resolution: | Keywords: Operating System: Unknown/Multiple | Architecture: Type of failure: Runtime | Unknown/Multiple performance bug | Test Case: Blocked By: | Blocking: Related Tickets: #8598 | Differential Revisions: -------------------------------------+------------------------------------- Comment (by nomeata): I do not know how much the code changed in master... just give it a try! -- Ticket URL: <http://ghc.haskell.org/trac/ghc/ticket/1600#comment:48> GHC <http://www.haskell.org/ghc/> The Glasgow Haskell Compiler

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Re: [GHC] #1600: Optimisation: CPR the results of IO
by GHC 02 Aug '15

02 Aug '15

#1600: Optimisation: CPR the results of IO -------------------------------------+------------------------------------- Reporter: simonmar | Owner: Type: task | Status: new Priority: lowest | Milestone: 7.12.1 Component: Compiler | Version: 6.6.1 Resolution: | Keywords: Operating System: Unknown/Multiple | Architecture: Type of failure: Runtime | Unknown/Multiple performance bug | Test Case: Blocked By: | Blocking: Related Tickets: #8598 | Differential Revisions: -------------------------------------+------------------------------------- Changes (by akio): * cc: akio (added) -- Ticket URL: <http://ghc.haskell.org/trac/ghc/ticket/1600#comment:47> GHC <http://www.haskell.org/ghc/> The Glasgow Haskell Compiler

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