#4856: Performance regression in the type checker regression for GADTs and type
families
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Reporter: chak | Owner:
Type: bug | Status: new
Priority: normal | Component: Compiler (Type checker)
Version: 7.0.1 | Keywords:
Testcase: | Blockedby:
Os: Unknown/Multiple | Blocking:
Architecture: Unknown/Multiple | Failure: GHC rejects valid program
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The GHC 7.0.2 RC1 shows poor performance when compiling
`Data.Array.Accelerate`. In particular, to type check a particular
module, GHC 7.02 takes several minutes, while GHC's resident memory grows
to 350MB. In contrast, GHC 6.12.3 compiles the same module in a few
seconds.
How to reproduce the problem:
0. Download the latest version of `Data.Array.Accelerate` with darcs from
[http://code.haskell.org/accelerate/]
1. Change directory to the new `accelerate` darcs repo.
2. Invoke GHCi as `ghci -Iinclude`.
3. Issue the GHCi command: `:l Data/Array/Accelerate/Smart.hs`
You will notice that `Data.Arra.Accelerate.Array.Sugar`, which is heavy in
type classes and type families, already requires a noticeable time to
compile — this is already a performance regression from 6.12.3. The
module `Data.Array.Accelerate.Smart` requires an even much longer time to
compile.
--
Ticket URL: <http://hackage.haskell.org/trac/ghc/ticket/4856>
GHC <http://www.haskell.org/ghc/>
The Glasgow Haskell Compiler
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