diff options
| -rw-r--r-- | compiler/basicTypes/BasicTypes.hs | 2 | ||||
| -rw-r--r-- | compiler/basicTypes/Demand.hs | 5 | ||||
| -rw-r--r-- | compiler/basicTypes/MkId.hs | 9 | ||||
| -rw-r--r-- | compiler/coreSyn/CoreTidy.hs | 3 | ||||
| -rw-r--r-- | compiler/iface/IfaceType.hs | 4 |
5 files changed, 11 insertions, 12 deletions
diff --git a/compiler/basicTypes/BasicTypes.hs b/compiler/basicTypes/BasicTypes.hs index 04353bf3d0..973666d0f8 100644 --- a/compiler/basicTypes/BasicTypes.hs +++ b/compiler/basicTypes/BasicTypes.hs @@ -163,7 +163,7 @@ type Alignment = Int -- align to next N-byte boundary (N must be a power of 2). data OneShotInfo = NoOneShotInfo -- ^ No information | ProbOneShot -- ^ The lambda is probably applied at most once - -- See Note [Computing one-shot info, and ProbOneShot] in OccurAnl + -- See Note [Computing one-shot info, and ProbOneShot] in Demand | OneShotLam -- ^ The lambda is applied at most once. deriving (Eq) diff --git a/compiler/basicTypes/Demand.hs b/compiler/basicTypes/Demand.hs index ecf22bc51f..3ca7c2d801 100644 --- a/compiler/basicTypes/Demand.hs +++ b/compiler/basicTypes/Demand.hs @@ -1618,9 +1618,8 @@ argOneShots one_shot_info (JD { absd = usg }) go (UCall Many u) = NoOneShotInfo : go u go _ = [] -{- -Note [Computing one-shot info, and ProbOneShot] -~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~ +{- Note [Computing one-shot info, and ProbOneShot] +~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~ Consider a call f (\pqr. e1) (\xyz. e2) e3 where f has usage signature diff --git a/compiler/basicTypes/MkId.hs b/compiler/basicTypes/MkId.hs index 0b22a6480d..c4222be0f5 100644 --- a/compiler/basicTypes/MkId.hs +++ b/compiler/basicTypes/MkId.hs @@ -1250,7 +1250,6 @@ appears un-applied, we'll end up just calling it. Note [The oneShot function] ~~~~~~~~~~~~~~~~~~~~~~~~~~~ - In the context of making left-folds fuse somewhat okish (see ticket #7994 and Note [Left folds via right fold]) it was determined that it would be useful if library authors could explicitly tell the compiler that a certain lambda is @@ -1270,9 +1269,11 @@ after unfolding the definition `oneShot = \f \x[oneshot]. f x` we get --> \x[oneshot] e[x/y] which is what we want. -It is only effective if this bits survives as long as possible and makes it into -the interface in unfoldings (See Note [Preserve OneShotInfo]). Also see -https://ghc.haskell.org/trac/ghc/wiki/OneShot. +It is only effective if the one-shot info survives as long as possible; in +particular it must make it into the interface in unfoldings. See Note [Preserve +OneShotInfo] in CoreTidy. + +Also see https://ghc.haskell.org/trac/ghc/wiki/OneShot. Note [magicDictId magic] diff --git a/compiler/coreSyn/CoreTidy.hs b/compiler/coreSyn/CoreTidy.hs index 325950cf16..4ee867ad0a 100644 --- a/compiler/coreSyn/CoreTidy.hs +++ b/compiler/coreSyn/CoreTidy.hs @@ -258,12 +258,11 @@ but that seems more indirect and surprising.) Note [Preserve OneShotInfo] ~~~~~~~~~~~~~~~~~~~~~~~~~~~ - We keep the OneShotInfo because we want it to propagate into the interface. Not all OneShotInfo is determined by a compiler analysis; some is added by a call of GHC.Exts.oneShot, which is then discarded before the end of the optimisation pipeline, leaving only the OneShotInfo on the lambda. Hence we -must preserve this info in inlinings. +must preserve this info in inlinings. See Note [The oneShot function] in MkId. This applies to lambda binders only, hence it is stored in IfaceLamBndr. -} diff --git a/compiler/iface/IfaceType.hs b/compiler/iface/IfaceType.hs index fed3ffc303..e83c25e511 100644 --- a/compiler/iface/IfaceType.hs +++ b/compiler/iface/IfaceType.hs @@ -87,8 +87,8 @@ type IfaceIdBndr = (IfLclName, IfaceType) type IfaceTvBndr = (IfLclName, IfaceKind) -data IfaceOneShot -- see Note [Preserve OneShotInfo] - = IfaceNoOneShot +data IfaceOneShot -- See Note [Preserve OneShotInfo] in CoreTicy + = IfaceNoOneShot -- and Note [The oneShot function] in MkId | IfaceOneShot type IfaceLamBndr |