June 2014 - ghc-tickets

[GHC] #8704: Use GHC.Exts.build in randoms, randomRs to achieve fusion
by GHC 02 Jul '14

02 Jul '14

#8704: Use GHC.Exts.build in randoms, randomRs to achieve fusion ------------------------------------+------------------------------------- Reporter: ion1 | Owner: Type: feature request | Status: new Priority: normal | Milestone: Component: libraries/random | Version: 7.6.3 Keywords: fusion | Operating System: Unknown/Multiple Architecture: Unknown/Multiple | Type of failure: None/Unknown Difficulty: Unknown | Test Case: Blocked By: | Blocking: Related Tickets: #4218 | ------------------------------------+------------------------------------- randoms, randomRs could take advantage of list fusion. A commit is attached for consideration. -- Ticket URL: <http://ghc.haskell.org/trac/ghc/ticket/8704> GHC <http://www.haskell.org/ghc/> The Glasgow Haskell Compiler

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[GHC] #9102: Assertion failure in CoreUtils.lhs
by GHC 02 Jul '14

02 Jul '14

#9102: Assertion failure in CoreUtils.lhs ------------------------------------+------------------------------------- Reporter: tmcdonell | Owner: Type: bug | Status: new Priority: normal | Milestone: Component: Compiler | Version: 7.8.2 Keywords: | Operating System: Unknown/Multiple Architecture: Unknown/Multiple | Type of failure: None/Unknown Difficulty: Unknown | Test Case: Blocked By: | Blocking: Related Tickets: | ------------------------------------+------------------------------------- I happened to be using a debug build of ghc-7.8.2, and got this assertion failure compiling [http://hackage.haskell.org/package/fclabels-2.0.1 fclabels]. {{{ [ 7 of 10] Compiling Data.Label.Total ( src/Data/Label/Total.hs, dist/build/Data/Label/Total.o ) <no location info>: ghc: panic! (the 'impossible' happened) (GHC version 7.8.2.20140429 for x86_64-unknown-linux): ASSERT failed! file compiler/coreSyn/CoreUtils.lhs line 194 coercion Nth:0 dt{v d7gF} [lid] passed to mkCast base:Control.Category.id{v rkl} [gid[ClassOp]] @ ghc- prim:GHC.Prim.*{(w) tc 34d} @ fclabels-2.0.1:Data.Label.Point.Total{tc r1Pm} (base:Control.Arrow.$p1Arrow{v r1s} [gid[ClassOp]] @ fclabels-2.0.1:Data.Label.Point.Total{tc r1Pm} (base:Control.Arrow.$p1ArrowApply{v rp} [gid[ClassOp]] @ fclabels-2.0.1:Data.Label.Point.Total{tc r1Pm} $dArrowApply{v a72o} [lid])) @ f{tv a8m6} [tv] f{v a8hw} [lid] has wrong role nominal }}} Problem does not appear with `-O0`. I couldn't test with HEAD because fclabels isn't compatible with the changes to Template Haskell yet. -- Ticket URL: <http://ghc.haskell.org/trac/ghc/ticket/9102> GHC <http://www.haskell.org/ghc/> The Glasgow Haskell Compiler

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[GHC] #9208: panic - attempt to prod-split strictness call demand C(S(C(C(S(LS)))))
by GHC 02 Jul '14

02 Jul '14

#9208: panic - attempt to prod-split strictness call demand C(S(C(C(S(LS))))) ------------------------------------+------------------------------------- Reporter: luite | Owner: Type: bug | Status: new Priority: normal | Milestone: Component: Compiler | Version: 7.8.2 Keywords: | Operating System: Unknown/Multiple Architecture: Unknown/Multiple | Type of failure: None/Unknown Difficulty: Unknown | Test Case: Blocked By: | Blocking: Related Tickets: | ------------------------------------+------------------------------------- tested with GHC 7.8 branch commit 32b4bf33989bdda4dffed1866f7a61a7da4ca275 and GHC 7.8.2 compile with -O or -O2 -- Ticket URL: <http://ghc.haskell.org/trac/ghc/ticket/9208> GHC <http://www.haskell.org/ghc/> The Glasgow Haskell Compiler

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[GHC] #9254: Entered absent argument (again)
by GHC 02 Jul '14

02 Jul '14

#9254: Entered absent argument (again) ------------------------------------+------------------------------------- Reporter: simonpj | Owner: Type: bug | Status: new Priority: normal | Milestone: 7.8.4 Component: Compiler | Version: 7.8.2 Keywords: | Operating System: Unknown/Multiple Architecture: Unknown/Multiple | Type of failure: None/Unknown Difficulty: Unknown | Test Case: Blocked By: | Blocking: Related Tickets: | ------------------------------------+------------------------------------- Consider this program: {{{ {-# LANGUAGE MagicHash, UnboxedTuples #-} module Main where import GHC.Exts f :: (() -> (# Int#, () #)) -> () {-# NOINLINE f #-} -- Strictness signature was (7.8.2) -- <C(S(LS)), 1*C1(U(A,1*U()))> -- I.e. calls k, but discards first component of result f k = case k () of (# _, r #) -> r g :: Int -> () g y = f (\n -> (# case y of I# y2 -> h (h (h (h (h (h (h y2)))))), n #)) -- RHS is big enough to force worker/wrapper {-# NOINLINE h #-} h :: Int# -> Int# h n = n +# 1# main = print (g 1) }}} You'll get {{{ bash$ ghc -O -o foo Foo.hs bash$ ./foo foo: Oops! Entered absent arg w_s4vl Int }}} Ugh! This is the bug underlying [https://github.com/bos/vector-binary- instances/issues/4 this bug report]. I know what is going on. -- Ticket URL: <http://ghc.haskell.org/trac/ghc/ticket/9254> GHC <http://www.haskell.org/ghc/> The Glasgow Haskell Compiler

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[GHC] #9172: integer overflow in allocate()
by GHC 02 Jul '14

02 Jul '14

#9172: integer overflow in allocate() ------------------------------------+------------------------------------- Reporter: rwbarton | Owner: rwbarton Type: bug | Status: new Priority: normal | Milestone: Component: Runtime System | Version: 7.8.1 Keywords: | Operating System: Unknown/Multiple Architecture: Unknown/Multiple | Type of failure: None/Unknown Difficulty: Unknown | Test Case: Blocked By: | Blocking: Related Tickets: | ------------------------------------+------------------------------------- {{{ Prelude> Data.Array.array (0,2^61 * 1024 `div` 1025) [] array (0,<interactive>: internal error: evacuate: strange closure type 2131681697 (GHC version 7.8.1 for x86_64_unknown_linux) Please report this as a GHC bug: http://www.haskell.org/ghc/reportabug Aborted }}} You can get a variety of other errors too. The array size is chosen so that the total size (in words) passed to `allocate` is just a bit over 2^61^. The computation of `req_blocks` overflows: {{{ W_ req_blocks = (W_)BLOCK_ROUND_UP(n*sizeof(W_)) / BLOCK_SIZE; }}} -- Ticket URL: <http://ghc.haskell.org/trac/ghc/ticket/9172> GHC <http://www.haskell.org/ghc/> The Glasgow Haskell Compiler

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[GHC] #9085: Inaccessible equations in a closed type family should be a warning, not an error
by GHC 02 Jul '14

02 Jul '14

#9085: Inaccessible equations in a closed type family should be a warning, not an error ------------------------------------+------------------------------------- Reporter: goldfire | Owner: goldfire Type: bug | Status: new Priority: normal | Milestone: Component: Compiler | Version: 7.8.2 Keywords: | Operating System: Unknown/Multiple Architecture: Unknown/Multiple | Type of failure: None/Unknown Difficulty: Unknown | Test Case: Blocked By: | Blocking: Related Tickets: | ------------------------------------+------------------------------------- If I say {{{ foo _ = () foo False = () }}} I get {{{ /Users/rae/temp/Bug.hs:2:1: Warning: Pattern match(es) are overlapped In an equation for ‘foo’: foo False = ... }}} But, if I say {{{ {-# LANGUAGE TypeFamilies #-} type family Foo a where Foo x = () Foo Bool = () }}} I get {{{ /Users/rae/temp/Bug.hs:5:3: Inaccessible family instance equation: Foo Bool = () In the equations for closed type family ‘Foo’ In the type family declaration for ‘Foo’ }}} If this issues a warning at the term level, it probably should do the same at the type level. This was my design decision that I'm changing, and I will fix. The warning will be controlled by the same flag that controls the term-level version. -- Ticket URL: <http://ghc.haskell.org/trac/ghc/ticket/9085> GHC <http://www.haskell.org/ghc/> The Glasgow Haskell Compiler

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[GHC] #8787: compiler/ghc.mk: restore GhcHcOpts variable handling
by GHC 02 Jul '14

02 Jul '14

#8787: compiler/ghc.mk: restore GhcHcOpts variable handling ------------------------------------+------------------------------------- Reporter: slyfox | Owner: Type: bug | Status: new Priority: normal | Milestone: Component: Compiler | 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: | ------------------------------------+------------------------------------- wiki and mk/config.mk.in suggests setting GhcHcOpts for compiler-wide haskell flags. But it does not work for a while now. Proposed patch fixes it. Thanks! -- Ticket URL: <http://ghc.haskell.org/trac/ghc/ticket/8787> GHC <http://www.haskell.org/ghc/> The Glasgow Haskell Compiler

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[GHC] #8993: Fold NullaryTypeClasses into MPTC
by GHC 01 Jul '14

01 Jul '14

#8993: Fold NullaryTypeClasses into MPTC ------------------------------------+------------------------------------- Reporter: owst | Owner: Type: bug | Status: new Priority: normal | Milestone: Component: Compiler | Version: 7.8.2 Keywords: | Operating System: Unknown/Multiple Architecture: Unknown/Multiple | Type of failure: None/Unknown Difficulty: Unknown | Test Case: Blocked By: | Blocking: Related Tickets: | ------------------------------------+------------------------------------- NullaryTypeClasses are an instance of MultiParamTypeClasses, so make it so. Suggested by Austin [http://www.reddit.com/r/haskell/comments/22lw1b/ghc_781_released/cgoi79c on reddit] -- Ticket URL: <http://ghc.haskell.org/trac/ghc/ticket/8993> GHC <http://www.haskell.org/ghc/> The Glasgow Haskell Compiler

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[GHC] #8425: ghc-7.6.3: crossmodule inline leads to buggy code (-O2)
by GHC 01 Jul '14

01 Jul '14

#8425: ghc-7.6.3: crossmodule inline leads to buggy code (-O2) ----------------------------------+------------------------------------- Reporter: slyfox | Owner: Type: bug | Status: new Priority: normal | Milestone: Component: Compiler | Version: 7.6.3 Keywords: | Operating System: Unknown/Multiple Architecture: x86_64 (amd64) | Type of failure: Runtime crash Difficulty: Unknown | Test Case: Blocked By: | Blocking: Related Tickets: | ----------------------------------+------------------------------------- The bug is found as a crash of gf-3.4 ('Grammatical Framework') package compiled with -O2. With some debugging I've come to roughly following minimal example: This code compiles incorrectly: {{{ import BuggyOpt() -- bug inducer! import qualified Data.Map as Map import Data.Array.IArray {-# NOINLINE mkLin #-} mkLin :: Array Int (Array Int Int) -> Map.Map (Array Int Int) Int -> Int -> (Map.Map (Array Int Int) Int, Int) mkLin mseqs seqs seqid = let seq_ = mseqs ! seqid -- lookup/insert pair. exactly as in 'BuggyOpt' module in case Map.lookup seq_ seqs of Just seqid' -> (seqs,seqid') Nothing -> let seqid'' = Map.size seqs seqs' = Map.insert seq_ seqid'' seqs in (seqs',seqid'') }}} And this works fine: {{{ --import BuggyOpt() -- bug inducer! import qualified Data.Map as Map import Data.Array.IArray {-# NOINLINE mkLin #-} mkLin :: Array Int (Array Int Int) -> Map.Map (Array Int Int) Int -> Int -> (Map.Map (Array Int Int) Int, Int) mkLin mseqs seqs seqid = let seq_ = mseqs ! seqid -- lookup/insert pair. exactly as in 'BuggyOpt' module in case Map.lookup seq_ seqs of Just seqid' -> (seqs,seqid') Nothing -> let seqid'' = Map.size seqs seqs' = Map.insert seq_ seqid'' seqs in (seqs',seqid'') }}} Attached minimal test tarball and my results on it are: {{{ [("Project name","The Glorious Glasgow Haskell Compilation System") ,("GCC extra via C opts"," -fwrapv") ,("C compiler command","x86_64-pc-linux-gnu-gcc") ,("C compiler flags"," -fno-stack-protector -Wl,--hash-size=31 -Wl ,--reduce-memory-overheads") ,("ar command","/usr/bin/ar") ,("ar flags","q") ,("ar supports at file","YES") ,("touch command","touch") ,("dllwrap command","/bin/false") ,("windres command","/bin/false") ,("perl command","/usr/bin/perl") ,("target os","OSLinux") ,("target arch","ArchX86_64") ,("target word size","8") ,("target has GNU nonexec stack","True") ,("target has .ident directive","True") ,("target has subsections via symbols","False") ,("LLVM llc command","/usr/bin/llc") ,("LLVM opt command","/usr/bin/opt") ,("Project version","7.6.3") ,("Booter version","7.6.3") ,("Stage","2") ,("Build platform","x86_64-unknown-linux") ,("Host platform","x86_64-unknown-linux") ,("Target platform","x86_64-unknown-linux") ,("Have interpreter","YES") ,("Object splitting supported","YES") ,("Have native code generator","YES") ,("Support SMP","YES") ,("Unregisterised","NO") ,("Tables next to code","YES") ,("RTS ways","l debug thr thr_debug thr_l thr_p dyn debug_dyn thr_dyn thr_debug_dyn") ,("Leading underscore","NO") ,("Debug on","False") ,("LibDir","/usr/lib64/ghc-7.6.3") ,("Global Package DB","/usr/lib64/ghc-7.6.3/package.conf.d") ,("Gcc Linker flags","[\"-Wl,--hash-size=31\",\"-Wl,--reduce-memory- overheads\"]") ,("Ld Linker flags","[\"--hash-size=31\",\"--reduce-memory-overheads\"]") ] RUN good [1 of 2] Compiling Susp ( good/Susp.hs, good/Susp.o ) [2 of 2] Compiling Main ( good/main.hs, good/main.o ) Linking good/main ... (fromList [(array (0,0) [(0,42)],0)],0) RUN bad [1 of 3] Compiling BuggyOpt ( bad/BuggyOpt.hs, bad/BuggyOpt.o ) [2 of 3] Compiling Susp ( bad/Susp.hs, bad/Susp.o ) [3 of 3] Compiling Main ( bad/main.hs, bad/main.o ) Linking bad/main ... main: Error in array index; 0 not in range [0..0) TEST FAILED in bad }}} What we see here is the test with useless import mysteriously fails: > main: Error in array index; 0 not in range [0..0) while without import it works fine: > (fromList [(array (0,0) [(0,42)],0)],0) The functions in both BuggyOpt and Susp modules contain suspiciously similar code: {{{ case Map.lookup seq' seqs of Just id' -> (seqs,id') Nothing -> let last_seq = Map.size seqs in (Map.insert seq' last_seq seqs, last_seq) }}} But in BuggyOpt ghc somehow deduces some arguments and applies that effect to (unrelated, but looking similar) Susp module. Thanks! -- Ticket URL: <http://ghc.haskell.org/trac/ghc/ticket/8425> GHC <http://www.haskell.org/ghc/> The Glasgow Haskell Compiler

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[GHC] #9145: hp2ps produces odd negative sawtooth
by GHC 01 Jul '14

01 Jul '14

#9145: hp2ps produces odd negative sawtooth --------------------------+------------------------------------------------ Reporter: | Owner: blackdog | Status: new Type: bug | Milestone: Priority: normal | Version: 7.8.2 Component: | Operating System: Linux Profiling | Type of failure: Incorrect result at runtime Keywords: | Test Case: Architecture: | Blocking: Unknown/Multiple | Difficulty: | Unknown | Blocked By: | Related Tickets: | --------------------------+------------------------------------------------ i'm profiling a process with about 22gb of usage before the OOMkiller gets it. the heap profile for it is very odd: -- Ticket URL: <http://ghc.haskell.org/trac/ghc/ticket/9145> GHC <http://www.haskell.org/ghc/> The Glasgow Haskell Compiler

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