#5321: Very slow constraint solving for type families
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Reporter: simonpj | Owner:
Type: bug | Status: new
Priority: low | Milestone: 7.6.1
Component: Compiler (Type checker) | Version: 7.0.3
Keywords: | Os: Unknown/Multiple
Architecture: Unknown/Multiple | Failure: Compile-time
performance bug
Difficulty: Unknown | Testcase: perf/compiler/T5321Fun,
T5321FD
Blockedby: | Blocking:
Related: |
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Comment(by dimitris):
With the changes I've made things have been improved. With functional
dependencies:
{{{
testHMapFoo1 0.21sec 96MB
testHMapFoo2 0.21sec 95MB
testHMapFoo3 0.20sec 92MB
}}}
I dont understand very well your third allocation number Simon (you meant
Mbytes?)
With type families we get:
{{{
testHMapFoo1 0.21sec 117MB
testHMapFoo2 0.29sec 124MB
testHMapFoo3 0.29sec 125MB
}}}
So they are much more comparable (and faster too!). The slightly higher
allocation I believe is probably caused because with type families there's
evidence around whereas with Derived constraints from fundeps that's not
the case.
This all is in my branch but I will push to HEAD shortly. The file is
already in the testuite.
--
Ticket URL: <http://hackage.haskell.org/trac/ghc/ticket/5321#comment:5>
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