#4495: GHC fails to inline methods of single-method classes
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Reporter: diatchki | Owner: igloo
Type: bug | Status: new
Priority: normal | Milestone: 7.0.2
Component: Compiler | Version: 7.1
Keywords: | Testcase:
Blockedby: | Difficulty:
Os: Unknown/Multiple | Blocking:
Architecture: Unknown/Multiple | Failure: Runtime performance bug
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Changes (by simonpj):
* owner: => igloo
Comment:
Yes, I've been meaning to get back to this. This patch fixes it
{{{
Tue Dec 21 16:19:11 GMT 2010 [email protected]
* Single-method classes are implemented with a newtype
This patch changes things so that such classes rely on the coercion
mechanism for inlining (since the constructor is really just a cast)
rather than on the dfun mechanism, therby removing some needless
runtime indirections.
M ./compiler/basicTypes/MkId.lhs -7 +10
M ./compiler/typecheck/TcInstDcls.lhs -23 +24
}}}
It's not clear to me how to add a regression test. Ian, if you can,
please do.
If this gets pushed into the stable branch then fine, but no special need
to do so.
Simon
--
Ticket URL: <http://hackage.haskell.org/trac/ghc/ticket/4495#comment:2>
GHC <http://www.haskell.org/ghc/>
The Glasgow Haskell Compiler
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