#5327: INLINABLE pragma and newtypes prevents inlining
---------------------------------+------------------------------------------
Reporter: reinerp | Owner:
Type: bug | Status: new
Priority: normal | Component: Compiler
Version: 7.1 | Keywords:
Testcase: | Blockedby:
Os: Unknown/Multiple | Blocking:
Architecture: Unknown/Multiple | Failure: Runtime performance bug
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Compile the following code with 'ghc -O2 -ddump-simpl':
{{{
module A where
newtype Size = Size Int
{-# INLINABLE val2 #-}
val2 = Size 0
f n = case val2 of Size s -> s + s > n
}}}
With ghc-7.1.20110629, we get the following Core:
{{{
A.f1 =
case A.val2 `cast` (A.NTCo:Size :: A.Size ~ GHC.Types.Int)
of _ { GHC.Types.I# x_aoz ->
GHC.Types.I# (GHC.Prim.+# x_aoz x_aoz)
}
A.f = \ (n_ab1 :: GHC.Types.Int) -> GHC.Classes.gtInt A.f1 n_ab1
}}}
and we get something similar with ghc-7.0.3. In particular, for both
versions of ghc, the addition {{{s+s}}} should be simplified to {{{0}}},
but isn't.
Any of the following changes will let {{{s+s}}} simplify to {{{0}}}:
* change {{{newtype Size = ...}}} into {{{data Size = ...}}}
* remove the INLINABLE pragma
* with ghc-7.0.3, turning the INLINABLE pragma into INLINE. However, with
ghc-7.1.20110629, the INLINE pragma doesn't fix the problem.
--
Ticket URL: <http://hackage.haskell.org/trac/ghc/ticket/5327>
GHC <http://www.haskell.org/ghc/>
The Glasgow Haskell Compiler
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