#6048: Exponential inlining code blowup
---------------------------------+------------------------------------------
Reporter: simonpj | Owner:
Type: bug | Status: new
Priority: normal | Milestone:
Component: Compiler | Version: 7.4.1
Keywords: | Os: Unknown/Multiple
Architecture: Unknown/Multiple | Failure: None/Unknown
Difficulty: Unknown | Testcase:
Blockedby: | Blocking:
Related: |
---------------------------------+------------------------------------------
(Transferring a new thread from #5539 to a new ticket, since it's really a
separate problem.) kosmikus helpfully provided this program
{{{
module TestCase where
import Control.Applicative
data X = X
(Maybe String)
(Maybe String)
(Maybe String)
(Maybe String)
(Maybe String)
(Maybe String)
(Maybe String)
(Maybe String)
(Maybe String)
mb :: (String -> Maybe a) -> String -> Maybe (Maybe a)
mb _ "" = Just Nothing
mb _ "-" = Just Nothing
mb p xs = Just <$> p xs
run :: [String] -> Maybe X
run
[ x1
, x2
, x3
, x4
, x5
, x6
, x7
, x8
, x9
] = X
<$> mb pure x1
<*> mb pure x2
<*> mb pure x3
<*> mb pure x4
<*> mb pure x5
<*> mb pure x6
<*> mb pure x7
<*> mb pure x8
<*> mb pure x9
}}}
Unless `mb` is marked as `NOINLINE`, it gets expanded in the body of run a
number of times that seems to grow exponentially with the size of the list
(9 in the example).
--
Ticket URL: <http://hackage.haskell.org/trac/ghc/ticket/6048>
GHC <http://www.haskell.org/ghc/>
The Glasgow Haskell Compiler
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