diff options
Diffstat (limited to 'libraries/ghc-prim/GHC/Magic.hs')
| -rw-r--r-- | libraries/ghc-prim/GHC/Magic.hs | 11 |
1 files changed, 10 insertions, 1 deletions
diff --git a/libraries/ghc-prim/GHC/Magic.hs b/libraries/ghc-prim/GHC/Magic.hs index 081b838c46..1a6af9237d 100644 --- a/libraries/ghc-prim/GHC/Magic.hs +++ b/libraries/ghc-prim/GHC/Magic.hs @@ -17,7 +17,7 @@ -- ----------------------------------------------------------------------------- -module GHC.Magic ( inline, lazy ) where +module GHC.Magic ( inline, lazy, oneShot ) where -- | The call @inline f@ arranges that 'f' is inlined, regardless of -- its size. More precisely, the call @inline f@ rewrites to the @@ -64,3 +64,12 @@ lazy x = x -- sees it as lazy. Then the worker/wrapper phase inlines it. -- Result: happiness + +-- | The 'oneShot' function can be used to give a hint to the compiler that its +-- argument will be called at most once, which may (or may not) enable certain +-- optimizations. It can be useful to improve the performance of code in continuation +-- passing style. +oneShot :: (a -> b) -> (a -> b) +oneShot f = f +-- Implementation note: This is wired in in MkId.lhs, so the code here is +-- mostly there to have a place for the documentation. |