-{-# OPTIONS -fno-warn-missing-signatures #-}
module Vectorise ( vectorise )
where
import CoreSyn
import CoreMonad ( CoreM, getHscEnv )
import Type
-import Var
import Id
import OccName
import DynFlags
}
}
--- | Try to vectorise a top-level binding.
--- If it doesn't vectorise then return it unharmed.
+-- |Try to vectorise a top-level binding. If it doesn't vectorise then return it unharmed.
--
--- For example, for the binding
+-- For example, for the binding
--
--- @
--- foo :: Int -> Int
--- foo = \x -> x + x
--- @
---
--- we get
--- @
--- foo :: Int -> Int
--- foo = \x -> vfoo $: x
---
--- v_foo :: Closure void vfoo lfoo
--- v_foo = closure vfoo lfoo void
---
--- vfoo :: Void -> Int -> Int
--- vfoo = ...
+-- @
+-- foo :: Int -> Int
+-- foo = \x -> x + x
+-- @
--
--- lfoo :: PData Void -> PData Int -> PData Int
--- lfoo = ...
--- @
+-- we get
+-- @
+-- foo :: Int -> Int
+-- foo = \x -> vfoo $: x
--
--- @vfoo@ is the "vectorised", or scalar, version that does the same as the original
--- function foo, but takes an explicit environment.
---
--- @lfoo@ is the "lifted" version that works on arrays.
+-- v_foo :: Closure void vfoo lfoo
+-- v_foo = closure vfoo lfoo void
+--
+-- vfoo :: Void -> Int -> Int
+-- vfoo = ...
+--
+-- lfoo :: PData Void -> PData Int -> PData Int
+-- lfoo = ...
+-- @
--
--- @v_foo@ combines both of these into a `Closure` that also contains the
--- environment.
+-- @vfoo@ is the "vectorised", or scalar, version that does the same as the original
+-- function foo, but takes an explicit environment.
--
--- The original binding @foo@ is rewritten to call the vectorised version
--- present in the closure.
+-- @lfoo@ is the "lifted" version that works on arrays.
+--
+-- @v_foo@ combines both of these into a `Closure` that also contains the
+-- environment.
+--
+-- The original binding @foo@ is rewritten to call the vectorised version
+-- present in the closure.
+--
+-- Vectorisation may be surpressed by annotating a binding with a 'NOVECTORISE' pragma. If this
+-- pragma is used in a group of mutually recursive bindings, either all or no binding must have
+-- the pragma. If only some bindings are annotated, a fatal error is being raised.
+-- FIXME: Once we support partial vectorisation, we may be able to vectorise parts of a group, or
+-- we may emit a warning and refrain from vectorising the entire group.
--
vectTopBind :: CoreBind -> VM CoreBind
vectTopBind b@(NonRec var expr)
- = do
- (inline, _, expr') <- vectTopRhs [] var expr
- var' <- vectTopBinder var inline expr'
-
- -- Vectorising the body may create other top-level bindings.
- hs <- takeHoisted
-
- -- To get the same functionality as the original body we project
- -- out its vectorised version from the closure.
- cexpr <- tryConvert var var' expr
-
- return . Rec $ (var, cexpr) : (var', expr') : hs
- `orElseV`
- return b
-
+ = unlessNoVectDecl $
+ do { -- Vectorise the right-hand side, create an appropriate top-level binding and add it
+ -- to the vectorisation map.
+ ; (inline, isScalar, expr') <- vectTopRhs [] var expr
+ ; var' <- vectTopBinder var inline expr'
+ ; when isScalar $
+ addGlobalScalar var
+
+ -- We replace the original top-level binding by a value projected from the vectorised
+ -- closure and add any newly created hoisted top-level bindings.
+ ; cexpr <- tryConvert var var' expr
+ ; hs <- takeHoisted
+ ; return . Rec $ (var, cexpr) : (var', expr') : hs
+ }
+ `orElseV`
+ return b
+ where
+ unlessNoVectDecl vectorise
+ = do { hasNoVectDecl <- noVectDecl var
+ ; when hasNoVectDecl $
+ traceVt "NOVECTORISE" $ ppr var
+ ; if hasNoVectDecl then return b else vectorise
+ }
vectTopBind b@(Rec bs)
- = do
- (vars', _, exprs')
- <- fixV $ \ ~(_, inlines, rhss) ->
- do vars' <- sequence [vectTopBinder var inline rhs
+ = unlessSomeNoVectDecl $
+ do { (vars', _, exprs', hs) <- fixV $
+ \ ~(_, inlines, rhss, _) ->
+ do { -- Vectorise the right-hand sides, create an appropriate top-level bindings
+ -- and add them to the vectorisation map.
+ ; vars' <- sequence [vectTopBinder var inline rhs
| (var, ~(inline, rhs)) <- zipLazy vars (zip inlines rhss)]
- (inlines', areScalars', exprs')
- <- mapAndUnzip3M (uncurry $ vectTopRhs vars) bs
- if (and areScalars') || (length bs <= 1)
- then do
- return (vars', inlines', exprs')
- else do
- _ <- mapM deleteGlobalScalar vars
- (inlines'', _, exprs'') <- mapAndUnzip3M (uncurry $ vectTopRhs []) bs
- return (vars', inlines'', exprs'')
-
- hs <- takeHoisted
- cexprs <- sequence $ zipWith3 tryConvert vars vars' exprs
- return . Rec $ zip vars cexprs ++ zip vars' exprs' ++ hs
- `orElseV`
- return b
+ ; (inlines, areScalars, exprs') <- mapAndUnzip3M (uncurry $ vectTopRhs vars) bs
+ ; hs <- takeHoisted
+ ; if and areScalars
+ then -- (1) Entire recursive group is scalar
+ -- => add all variables to the global set of scalars
+ do { mapM_ addGlobalScalar vars
+ ; return (vars', inlines, exprs', hs)
+ }
+ else -- (2) At least one binding is not scalar
+ -- => vectorise again with empty set of local scalars
+ do { (inlines, _, exprs') <- mapAndUnzip3M (uncurry $ vectTopRhs []) bs
+ ; hs <- takeHoisted
+ ; return (vars', inlines, exprs', hs)
+ }
+ }
+
+ -- Replace the original top-level bindings by a values projected from the vectorised
+ -- closures and add any newly created hoisted top-level bindings to the group.
+ ; cexprs <- sequence $ zipWith3 tryConvert vars vars' exprs
+ ; return . Rec $ zip vars cexprs ++ zip vars' exprs' ++ hs
+ }
+ `orElseV`
+ return b
where
(vars, exprs) = unzip bs
-
+
+ unlessSomeNoVectDecl vectorise
+ = do { hasNoVectDecls <- mapM noVectDecl vars
+ ; when (and hasNoVectDecls) $
+ traceVt "NOVECTORISE" $ ppr vars
+ ; if and hasNoVectDecls
+ then return b -- all bindings have 'NOVECTORISE'
+ else if or hasNoVectDecls
+ then cantVectorise noVectoriseErr (ppr b) -- some (but not all) have 'NOVECTORISE'
+ else vectorise -- no binding has a 'NOVECTORISE' decl
+ }
+ noVectoriseErr = "NOVECTORISE must be used on all or no bindings of a recursive group"
+
-- | Make the vectorised version of this top level binder, and add the mapping
-- between it and the original to the state. For some binder @foo@ the vectorised
-- version is @$v_foo@
--
--- NOTE: vectTopBinder *MUST* be lazy in inline and expr because of how it is
--- used inside of fixV in vectTopBind
+-- NOTE: 'vectTopBinder' *MUST* be lazy in inline and expr because of how it is
+-- used inside of 'fixV' in 'vectTopBind'.
--
vectTopBinder :: Var -- ^ Name of the binding.
-> Inline -- ^ Whether it should be inlined, used to annotate it.
; case vectDecl of
Nothing -> return ()
Just (vdty, _)
- | coreEqType vty vdty -> return ()
+ | eqType vty vdty -> return ()
| otherwise ->
cantVectorise ("Type mismatch in vectorisation pragma for " ++ show var) $
(text "Expected type" <+> ppr vty)
where
rhs _globalScalar (Just (_, expr')) -- Case (1)
= return (inlineMe, False, expr')
- rhs True _vectDecl -- Case (2)
- = return (inlineMe, True, scalarRHS)
- -- FIXME: that True is not enough to register scalarness
- rhs False _vectDecl -- Case (3)
+ rhs True Nothing -- Case (2)
+ = do { expr' <- vectScalarFun True recFs expr
+ ; return (inlineMe, True, vectorised expr')
+ }
+ rhs False Nothing -- Case (3)
= do { let fvs = freeVars expr
; (inline, isScalar, vexpr) <- inBind var $
vectPolyExpr (isLoopBreaker $ idOccInfo var) recFs fvs
- ; if isScalar
- then addGlobalScalar var
- else deleteGlobalScalar var
; return (inline, isScalar, vectorised vexpr)
}
-
- -- For scalar right-hand sides, we know that the original binding will remain unaltered
- -- (hence, we can refer to it without risk of cycles) - cf, 'tryConvert'.
- scalarRHS = panic "Vectorise.scalarRHS: not implemented yet"
-- | Project out the vectorised version of a binding from some closure,
-- or return the original body if that doesn't work or the binding is scalar.
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