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Re: [GHC] #5763: Confusing error message
by GHC 17 Jul '13

17 Jul '13

#5763: Confusing error message -------------------------------------------------+------------------------- Reporter: simonpj | Owner: Type: bug | simonpj Priority: high | Status: new Component: Compiler | Milestone: 7.6.2 Resolution: | Version: 7.2.2 Operating System: Unknown/Multiple | Keywords: Type of failure: None/Unknown | Architecture: Test Case: indexed- | Unknown/Multiple types/should_fail/T5763 | Difficulty: Blocking: | Unknown | Blocked By: | Related Tickets: -------------------------------------------------+------------------------- Comment (by wira): can i know too problem solving -- Ticket URL: <http://ghc.haskell.org/trac/ghc/ticket/5763#comment:6> GHC <http://www.haskell.org/ghc/> The Glasgow Haskell Compiler

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Re: [GHC] #849: Offer control over branch prediction
by GHC 17 Jul '13

17 Jul '13

#849: Offer control over branch prediction -------------------------------------+------------------------------------ Reporter: simonpj | Owner: Type: feature request | Status: new Priority: normal | Milestone: 7.6.2 Component: Compiler | Version: 6.4.2 Resolution: | Keywords: Operating System: Unknown/Multiple | Architecture: Unknown/Multiple Type of failure: None/Unknown | Difficulty: Unknown Test Case: N/A | Blocked By: Blocking: | Related Tickets: -------------------------------------+------------------------------------ Changes (by jstolarek): * cc: jan.stolarek@… (added) -- Ticket URL: <http://ghc.haskell.org/trac/ghc/ticket/849#comment:23> GHC <http://www.haskell.org/ghc/> The Glasgow Haskell Compiler

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Re: [GHC] #1498: Optimisation: eliminate unnecessary heap check in recursive function
by GHC 17 Jul '13

17 Jul '13

#1498: Optimisation: eliminate unnecessary heap check in recursive function -------------------------------------+------------------------------------- Reporter: simonmar | Owner: Type: bug | Status: new Priority: low | Milestone: 7.6.2 Component: Compiler | Version: 6.6.1 Resolution: | Keywords: Operating System: Unknown/Multiple | Architecture: Unknown/Multiple Type of failure: Runtime | Difficulty: Moderate (less performance bug | than a day) Test Case: | Blocked By: 4258 Blocking: | Related Tickets: -------------------------------------+------------------------------------- Comment (by jstolarek): Is someone able to provide a complete code example that demonstrates this bug? I'd like to take a look. -- Ticket URL: <http://ghc.haskell.org/trac/ghc/ticket/1498#comment:21> GHC <http://www.haskell.org/ghc/> The Glasgow Haskell Compiler

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[GHC] #8062: Panic "Lookup local fingerprint main:Main.main{v r6xE}"
by GHC 17 Jul '13

17 Jul '13

#8062: Panic "Lookup local fingerprint main:Main.main{v r6xE}" ------------------------------------+--------------------------------- Reporter: tommd | Owner: Type: bug | Status: new Priority: normal | Milestone: Component: Compiler | Version: 7.6.3 Keywords: | Operating System: Linux Architecture: Unknown/Multiple | Type of failure: None/Unknown Difficulty: Unknown | Test Case: Blocked By: | Blocking: Related Tickets: | ------------------------------------+--------------------------------- When compiling some quickcheck tests for a larger internal project I receive the following error on my x86-64 Linux 3.10 system: {{{ ghc: panic! (the 'impossible' happened) (GHC version 7.6.3 for x86_64-unknown-linux): urk! lookup local fingerprint main:Main.main{v r6xE} Please report this as a GHC bug: http://www.haskell.org/ghc/reportabug }}} System info: {{{ $ ghc --version The Glorious Glasgow Haskell Compilation System, version 7.6.3 $ uname -a Linux Vodka 3.9.6-200.fc18.x86_64 #1 SMP Thu Jun 13 18:56:55 UTC 2013 x86_64 x86_64 x86_64 GNU/Linux $ gcc --version gcc (GCC) 4.7.2 20121109 (Red Hat 4.7.2-8) Copyright (C) 2012 Free Software Foundation, Inc. This is free software; see the source for copying conditions. There is NO warranty; not even for MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. $ ld --version GNU ld version 2.23.51.0.1-6.fc18 20120806 Copyright 2012 Free Software Foundation, Inc. This program is free software; you may redistribute it under the terms of the GNU General Public License version 3 or (at your option) a later version. This program has absolutely no warranty. }}} -- Ticket URL: <http://ghc.haskell.org/trac/ghc/ticket/8062> GHC <http://www.haskell.org/ghc/> The Glasgow Haskell Compiler

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[GHC] #8067: -XDefaultSignatures panic in type error diagnostic
by GHC 16 Jul '13

16 Jul '13

#8067: -XDefaultSignatures panic in type error diagnostic -------------------------------------+------------------------------------- Reporter: exFalso | Owner: Type: bug | Status: new Priority: normal | Milestone: Component: Compiler | Version: 7.6.3 Keywords: defaultsignatures | Operating System: Linux panic | Type of failure: Compile-time Architecture: x86_64 (amd64) | crash Difficulty: Unknown | Test Case: Blocked By: | Blocking: Related Tickets: | -------------------------------------+------------------------------------- The following piece of code shouldn't (and doesn't) typecheck, however GHC panics during the diagnostic. {{{ $ cat /tmp/Weird.hs {-# LANGUAGE DefaultSignatures #-} module Weird where import Control.Monad.Trans class Class a where fun :: () -> () -> a default fun :: () -> () -> m a fun = lift $ ghc /tmp/Weird.hs [1 of 1] Compiling Weird ( /tmp/Weird.hs, /tmp/Weird.o ) /tmp/Weird.hs:9:11: Couldn't match kind `* -> *' with `*' Expected type: ()ghc: panic! (the 'impossible' happened) (GHC version 7.6.3 for x86_64-unknown-linux): kindFunResult ghc-prim:GHC.Prim.*{(w) tc 34d} }}} -- Ticket URL: <http://ghc.haskell.org/trac/ghc/ticket/8067> GHC <http://www.haskell.org/ghc/> The Glasgow Haskell Compiler

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Re: [GHC] #5550: GHC infinite loop when compiling vector
by GHC 16 Jul '13

16 Jul '13

#5550: GHC infinite loop when compiling vector -------------------------------------------------+------------------------- Reporter: simonpj | Owner: Type: bug | Status: merge Priority: low | Milestone: 7.6.2 Component: Compiler | Version: 7.2.1 Resolution: | Keywords: Operating System: Unknown/Multiple | Architecture: Type of failure: None/Unknown | Unknown/Multiple Test Case: | Difficulty: simplCore/should_compile/T5550 | Unknown Blocking: | Blocked By: | Related Tickets: -------------------------------------------------+------------------------- Comment (by amosrobinson): Sorry for the late reply, I've been distracted. Yep, it's fixed in head. I'm guessing it will make it into the next release -- Ticket URL: <http://ghc.haskell.org/trac/ghc/ticket/5550#comment:33> GHC <http://www.haskell.org/ghc/> The Glasgow Haskell Compiler

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[GHC] #8063: Bad Bug URL
by GHC 16 Jul '13

16 Jul '13

#8063: Bad Bug URL ------------------------------------+------------------------------------- Reporter: tommd | Owner: Type: bug | Status: new Priority: low | Milestone: Component: Documentation | Version: 7.6.3 Keywords: | Operating System: Unknown/Multiple Architecture: Unknown/Multiple | Type of failure: None/Unknown Difficulty: Unknown | Test Case: Blocked By: | Blocking: Related Tickets: | ------------------------------------+------------------------------------- When the impossible actually happens, the message points the user to an old URL to report the bug: Please report this as a GHC bug: http://www.haskell.org/ghc/reportabug GHC should be updated to match the community's move. -- Ticket URL: <http://ghc.haskell.org/trac/ghc/ticket/8063> GHC <http://www.haskell.org/ghc/> The Glasgow Haskell Compiler

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Re: [GHC] #7624: Handling ImplicitParams in Instance Declaration
by GHC 16 Jul '13

16 Jul '13

#7624: Handling ImplicitParams in Instance Declaration --------------------------------------+------------------------------------ Reporter: philipjf | Owner: Type: bug | Status: new Priority: normal | Milestone: 7.8.1 Component: Documentation | Version: 7.6.1 Resolution: | Keywords: ImplicitParams Operating System: Unknown/Multiple | Architecture: Unknown/Multiple Type of failure: Documentation bug | Difficulty: Unknown Test Case: | Blocked By: Blocking: | Related Tickets: --------------------------------------+------------------------------------ Description changed by simonpj: Old description: > The GHC documentation states that ImplicitParam's may not be used in > class or instance declaration constraints. see for example > http://www.haskell.org/ghc/docs/7.6.1/html/users_guide/other-type- > extensions.html In practice though, at least on the Mac, all recent > version of GHC have permitted such instances. At the very least the > documentation should make clear that the compiler might permit such > instances, but they have undefined behaviour. Ideally, these would > simply be permitted. > > [http://joyoftypes.blogspot.com/2013/01/using-compiler-bugs-for-fun-and- > profit.html Why I think the (undocumented) current behavior is correct] New description: The GHC documentation states that `ImplicitParam`'s may not be used in class or instance declaration constraints. see for example http://www.haskell.org/ghc/docs/7.6.1/html/users_guide/other-type- extensions.html In practice though, at least on the Mac, all recent version of GHC have permitted such instances. At the very least the documentation should make clear that the compiler might permit such instances, but they have undefined behaviour. Ideally, these would simply be permitted. [http://joyoftypes.blogspot.com/2013/01/using-compiler-bugs-for-fun-and- profit.html Why I think the (undocumented) current behavior is correct] [[BR]] [http://www.reddit.com/r/haskell/comments/178w9u/using_compiler_bugs_for_fun… reddit discussion thereof] -- -- Ticket URL: <http://ghc.haskell.org/trac/ghc/ticket/7624#comment:4> GHC <http://www.haskell.org/ghc/> The Glasgow Haskell Compiler

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[GHC] #8059: internal error: setNumCapabilities: reducing the number of Capabilities is not currently supported.
by GHC 15 Jul '13

15 Jul '13

#8059: internal error: setNumCapabilities: reducing the number of Capabilities is not currently supported. -----------------------------------+--------------------------------------- Reporter: simons | Owner: Type: bug | Status: new Priority: normal | Milestone: Component: Compiler | Version: 7.4.2 Keywords: | Operating System: Linux Architecture: | Type of failure: Compile-time crash Unknown/Multiple | Test Case: Difficulty: Unknown | Blocking: Blocked By: | Related Tickets: | -----------------------------------+--------------------------------------- The test suite for abstract-deque-0.2.2 triggered the following crash in GHC 7.4.2 on Linux: internal error: setNumCapabilities: reducing the number of Capabilities is not currently supported. (GHC version 7.4.2 for x86_64_unknown_linux) Please report this as a GHC bug: http://www.haskell.org/ghc/reportabug I have attached a more complete copy of the build log. -- Ticket URL: <http://ghc.haskell.org/trac/ghc/ticket/8059> GHC <http://www.haskell.org/ghc/> The Glasgow Haskell Compiler

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Re: [GHC] #7116: Missing optimisation: strength reduction of floating-point multiplication
by GHC 14 Jul '13

14 Jul '13

#7116: Missing optimisation: strength reduction of floating-point multiplication --------------------------------------------+------------------------------ Reporter: simonmar | Owner: Type: bug | Status: patch Priority: normal | Milestone: 7.8.1 Component: Compiler | Version: 7.4.2 Resolution: | Keywords: Operating System: Unknown/Multiple | Architecture: Type of failure: Runtime performance bug | Unknown/Multiple Test Case: | Difficulty: Unknown Blocking: | Blocked By: | Related Tickets: --------------------------------------------+------------------------------ Comment (by simonmar): jstolarek: the ticket is about doing the optimisation for floating-point multiplication, not integer. We don't want to do it for integer operations, because it's better to do this in the code generator (the only reason for doing it in the simplifier would be to enable further simplifications, but that isn't the case here). Furthermore, we definitely want to optimise integer multiplication at the Cmm level, because the Stg->Cmm code generator and later stages may create opportunities for this optimisation. -- Ticket URL: <http://ghc.haskell.org/trac/ghc/ticket/7116#comment:7> GHC <http://www.haskell.org/ghc/> The Glasgow Haskell Compiler

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