{-# LANGUAGE OverloadedStrings #-}

-- | Loop simplification rules.
module Futhark.Optimise.Simplify.Rules.Loop (loopRules) where

import Control.Monad
import Data.Bifunctor (second)
import Data.List (partition)
import Data.Maybe
import Futhark.Analysis.DataDependencies
import Futhark.Analysis.PrimExp.Convert
import qualified Futhark.Analysis.SymbolTable as ST
import qualified Futhark.Analysis.UsageTable as UT
import Futhark.Construct
import Futhark.IR
import Futhark.IR.Prop.Aliases
import Futhark.Optimise.Simplify.Rule
import Futhark.Optimise.Simplify.Rules.ClosedForm
import Futhark.Optimise.Simplify.Rules.Index
import Futhark.Transform.Rename

-- This next one is tricky - it's easy enough to determine that some
-- loop result is not used after the loop, but here, we must also make
-- sure that it does not affect any other values.
--
-- I do not claim that the current implementation of this rule is
-- perfect, but it should suffice for many cases, and should never
-- generate wrong code.
removeRedundantMergeVariables :: BuilderOps rep => BottomUpRuleDoLoop rep
removeRedundantMergeVariables :: BottomUpRuleDoLoop rep
removeRedundantMergeVariables (SymbolTable rep
_, UsageTable
used) Pat (LetDec rep)
pat StmAux (ExpDec rep)
aux ([(FParam rep, SubExp)]
merge, LoopForm rep
form, Body rep
body)
  | Bool -> Bool
not (Bool -> Bool) -> Bool -> Bool
forall a b. (a -> b) -> a -> b
$ ((FParam rep, SubExp) -> Bool) -> [(FParam rep, SubExp)] -> Bool
forall (t :: * -> *) a. Foldable t => (a -> Bool) -> t a -> Bool
all (FParam rep -> Bool
forall dec. Param dec -> Bool
usedAfterLoop (FParam rep -> Bool)
-> ((FParam rep, SubExp) -> FParam rep)
-> (FParam rep, SubExp)
-> Bool
forall b c a. (b -> c) -> (a -> b) -> a -> c
. (FParam rep, SubExp) -> FParam rep
forall a b. (a, b) -> a
fst) [(FParam rep, SubExp)]
merge =
      let necessaryForReturned :: Names
necessaryForReturned =
            (FParam rep -> Bool)
-> [(FParam rep, SubExp)] -> Map VName Names -> Names
forall dec.
(Param dec -> Bool)
-> [(Param dec, SubExp)] -> Map VName Names -> Names
findNecessaryForReturned
              FParam rep -> Bool
forall dec. Param dec -> Bool
usedAfterLoopOrInForm
              ([FParam rep] -> [SubExp] -> [(FParam rep, SubExp)]
forall a b. [a] -> [b] -> [(a, b)]
zip (((FParam rep, SubExp) -> FParam rep)
-> [(FParam rep, SubExp)] -> [FParam rep]
forall a b. (a -> b) -> [a] -> [b]
map (FParam rep, SubExp) -> FParam rep
forall a b. (a, b) -> a
fst [(FParam rep, SubExp)]
merge) ((SubExpRes -> SubExp) -> [SubExpRes] -> [SubExp]
forall a b. (a -> b) -> [a] -> [b]
map SubExpRes -> SubExp
resSubExp ([SubExpRes] -> [SubExp]) -> [SubExpRes] -> [SubExp]
forall a b. (a -> b) -> a -> b
$ Body rep -> [SubExpRes]
forall rep. Body rep -> [SubExpRes]
bodyResult Body rep
body))
              (Body rep -> Map VName Names
forall rep. ASTRep rep => Body rep -> Map VName Names
dataDependencies Body rep
body)

          resIsNecessary :: ((Param dec, b), b) -> Bool
resIsNecessary ((Param dec
v, b
_), b
_) =
            Param dec -> Bool
forall dec. Param dec -> Bool
usedAfterLoop Param dec
v
              Bool -> Bool -> Bool
|| Param dec -> VName
forall dec. Param dec -> VName
paramName Param dec
v
              VName -> Names -> Bool
`nameIn` Names
necessaryForReturned
              Bool -> Bool -> Bool
|| Param dec -> Bool
forall dec. Param dec -> Bool
referencedInPat Param dec
v
              Bool -> Bool -> Bool
|| Param dec -> Bool
forall dec. Param dec -> Bool
referencedInForm Param dec
v

          ([(PatElem (LetDec rep), ((FParam rep, SubExp), SubExpRes))]
keep_valpart, [(PatElem (LetDec rep), ((FParam rep, SubExp), SubExpRes))]
discard_valpart) =
            ((PatElem (LetDec rep), ((FParam rep, SubExp), SubExpRes)) -> Bool)
-> [(PatElem (LetDec rep), ((FParam rep, SubExp), SubExpRes))]
-> ([(PatElem (LetDec rep), ((FParam rep, SubExp), SubExpRes))],
    [(PatElem (LetDec rep), ((FParam rep, SubExp), SubExpRes))])
forall a. (a -> Bool) -> [a] -> ([a], [a])
partition (((FParam rep, SubExp), SubExpRes) -> Bool
forall dec b b. ((Param dec, b), b) -> Bool
resIsNecessary (((FParam rep, SubExp), SubExpRes) -> Bool)
-> ((PatElem (LetDec rep), ((FParam rep, SubExp), SubExpRes))
    -> ((FParam rep, SubExp), SubExpRes))
-> (PatElem (LetDec rep), ((FParam rep, SubExp), SubExpRes))
-> Bool
forall b c a. (b -> c) -> (a -> b) -> a -> c
. (PatElem (LetDec rep), ((FParam rep, SubExp), SubExpRes))
-> ((FParam rep, SubExp), SubExpRes)
forall a b. (a, b) -> b
snd) ([(PatElem (LetDec rep), ((FParam rep, SubExp), SubExpRes))]
 -> ([(PatElem (LetDec rep), ((FParam rep, SubExp), SubExpRes))],
     [(PatElem (LetDec rep), ((FParam rep, SubExp), SubExpRes))]))
-> [(PatElem (LetDec rep), ((FParam rep, SubExp), SubExpRes))]
-> ([(PatElem (LetDec rep), ((FParam rep, SubExp), SubExpRes))],
    [(PatElem (LetDec rep), ((FParam rep, SubExp), SubExpRes))])
forall a b. (a -> b) -> a -> b
$
              [PatElem (LetDec rep)]
-> [((FParam rep, SubExp), SubExpRes)]
-> [(PatElem (LetDec rep), ((FParam rep, SubExp), SubExpRes))]
forall a b. [a] -> [b] -> [(a, b)]
zip (Pat (LetDec rep) -> [PatElem (LetDec rep)]
forall dec. Pat dec -> [PatElem dec]
patElems Pat (LetDec rep)
pat) ([((FParam rep, SubExp), SubExpRes)]
 -> [(PatElem (LetDec rep), ((FParam rep, SubExp), SubExpRes))])
-> [((FParam rep, SubExp), SubExpRes)]
-> [(PatElem (LetDec rep), ((FParam rep, SubExp), SubExpRes))]
forall a b. (a -> b) -> a -> b
$
                [(FParam rep, SubExp)]
-> [SubExpRes] -> [((FParam rep, SubExp), SubExpRes)]
forall a b. [a] -> [b] -> [(a, b)]
zip [(FParam rep, SubExp)]
merge ([SubExpRes] -> [((FParam rep, SubExp), SubExpRes)])
-> [SubExpRes] -> [((FParam rep, SubExp), SubExpRes)]
forall a b. (a -> b) -> a -> b
$
                  Body rep -> [SubExpRes]
forall rep. Body rep -> [SubExpRes]
bodyResult Body rep
body

          ([PatElem (LetDec rep)]
keep_valpatelems, [((FParam rep, SubExp), SubExpRes)]
keep_val) = [(PatElem (LetDec rep), ((FParam rep, SubExp), SubExpRes))]
-> ([PatElem (LetDec rep)], [((FParam rep, SubExp), SubExpRes)])
forall a b. [(a, b)] -> ([a], [b])
unzip [(PatElem (LetDec rep), ((FParam rep, SubExp), SubExpRes))]
keep_valpart
          ([PatElem (LetDec rep)]
_discard_valpatelems, [((FParam rep, SubExp), SubExpRes)]
discard_val) = [(PatElem (LetDec rep), ((FParam rep, SubExp), SubExpRes))]
-> ([PatElem (LetDec rep)], [((FParam rep, SubExp), SubExpRes)])
forall a b. [(a, b)] -> ([a], [b])
unzip [(PatElem (LetDec rep), ((FParam rep, SubExp), SubExpRes))]
discard_valpart
          ([(FParam rep, SubExp)]
merge', [SubExpRes]
val_es') = [((FParam rep, SubExp), SubExpRes)]
-> ([(FParam rep, SubExp)], [SubExpRes])
forall a b. [(a, b)] -> ([a], [b])
unzip [((FParam rep, SubExp), SubExpRes)]
keep_val

          body' :: Body rep
body' = Body rep
body {bodyResult :: [SubExpRes]
bodyResult = [SubExpRes]
val_es'}

          pat' :: Pat (LetDec rep)
pat' = [PatElem (LetDec rep)] -> Pat (LetDec rep)
forall dec. [PatElem dec] -> Pat dec
Pat [PatElem (LetDec rep)]
keep_valpatelems
       in if [(FParam rep, SubExp)]
merge' [(FParam rep, SubExp)] -> [(FParam rep, SubExp)] -> Bool
forall a. Eq a => a -> a -> Bool
== [(FParam rep, SubExp)]
merge
            then Rule rep
forall rep. Rule rep
Skip
            else RuleM rep () -> Rule rep
forall rep. RuleM rep () -> Rule rep
Simplify (RuleM rep () -> Rule rep) -> RuleM rep () -> Rule rep
forall a b. (a -> b) -> a -> b
$ do
              -- We can't just remove the bindings in 'discard', since the loop
              -- body may still use their names in (now-dead) expressions.
              -- Hence, we add them inside the loop, fully aware that dead-code
              -- removal will eventually get rid of them.  Some care is
              -- necessary to handle unique bindings.
              Body rep
body'' <- RuleM rep (Body (Rep (RuleM rep)))
-> RuleM rep (Body (Rep (RuleM rep)))
forall (m :: * -> *).
MonadBuilder m =>
m (Body (Rep m)) -> m (Body (Rep m))
insertStmsM (RuleM rep (Body (Rep (RuleM rep)))
 -> RuleM rep (Body (Rep (RuleM rep))))
-> RuleM rep (Body (Rep (RuleM rep)))
-> RuleM rep (Body (Rep (RuleM rep)))
forall a b. (a -> b) -> a -> b
$ do
                (([VName], Exp rep) -> RuleM rep ())
-> [([VName], Exp rep)] -> RuleM rep ()
forall (t :: * -> *) (m :: * -> *) a b.
(Foldable t, Monad m) =>
(a -> m b) -> t a -> m ()
mapM_ (([VName] -> Exp rep -> RuleM rep ())
-> ([VName], Exp rep) -> RuleM rep ()
forall a b c. (a -> b -> c) -> (a, b) -> c
uncurry [VName] -> Exp rep -> RuleM rep ()
forall (m :: * -> *).
MonadBuilder m =>
[VName] -> Exp (Rep m) -> m ()
letBindNames) ([([VName], Exp rep)] -> RuleM rep ())
-> [([VName], Exp rep)] -> RuleM rep ()
forall a b. (a -> b) -> a -> b
$ [((FParam rep, SubExp), SubExpRes)] -> [([VName], Exp rep)]
forall b rep. [((FParam rep, SubExp), b)] -> [([VName], Exp rep)]
dummyStms [((FParam rep, SubExp), SubExpRes)]
discard_val
                Body rep -> RuleM rep (Body rep)
forall (f :: * -> *) a. Applicative f => a -> f a
pure Body rep
body'
              StmAux (ExpDec rep) -> RuleM rep () -> RuleM rep ()
forall (m :: * -> *) anyrep a.
MonadBuilder m =>
StmAux anyrep -> m a -> m a
auxing StmAux (ExpDec rep)
aux (RuleM rep () -> RuleM rep ()) -> RuleM rep () -> RuleM rep ()
forall a b. (a -> b) -> a -> b
$ Pat (LetDec (Rep (RuleM rep)))
-> Exp (Rep (RuleM rep)) -> RuleM rep ()
forall (m :: * -> *).
MonadBuilder m =>
Pat (LetDec (Rep m)) -> Exp (Rep m) -> m ()
letBind Pat (LetDec rep)
Pat (LetDec (Rep (RuleM rep)))
pat' (Exp (Rep (RuleM rep)) -> RuleM rep ())
-> Exp (Rep (RuleM rep)) -> RuleM rep ()
forall a b. (a -> b) -> a -> b
$ [(FParam rep, SubExp)] -> LoopForm rep -> Body rep -> Exp rep
forall rep.
[(FParam rep, SubExp)] -> LoopForm rep -> Body rep -> Exp rep
DoLoop [(FParam rep, SubExp)]
merge' LoopForm rep
form Body rep
body''
  where
    pat_used :: [Bool]
pat_used = (VName -> Bool) -> [VName] -> [Bool]
forall a b. (a -> b) -> [a] -> [b]
map (VName -> UsageTable -> Bool
`UT.isUsedDirectly` UsageTable
used) ([VName] -> [Bool]) -> [VName] -> [Bool]
forall a b. (a -> b) -> a -> b
$ Pat (LetDec rep) -> [VName]
forall dec. Pat dec -> [VName]
patNames Pat (LetDec rep)
pat
    used_vals :: [VName]
used_vals = ((VName, Bool) -> VName) -> [(VName, Bool)] -> [VName]
forall a b. (a -> b) -> [a] -> [b]
map (VName, Bool) -> VName
forall a b. (a, b) -> a
fst ([(VName, Bool)] -> [VName]) -> [(VName, Bool)] -> [VName]
forall a b. (a -> b) -> a -> b
$ ((VName, Bool) -> Bool) -> [(VName, Bool)] -> [(VName, Bool)]
forall a. (a -> Bool) -> [a] -> [a]
filter (VName, Bool) -> Bool
forall a b. (a, b) -> b
snd ([(VName, Bool)] -> [(VName, Bool)])
-> [(VName, Bool)] -> [(VName, Bool)]
forall a b. (a -> b) -> a -> b
$ [VName] -> [Bool] -> [(VName, Bool)]
forall a b. [a] -> [b] -> [(a, b)]
zip (((FParam rep, SubExp) -> VName)
-> [(FParam rep, SubExp)] -> [VName]
forall a b. (a -> b) -> [a] -> [b]
map (FParam rep -> VName
forall dec. Param dec -> VName
paramName (FParam rep -> VName)
-> ((FParam rep, SubExp) -> FParam rep)
-> (FParam rep, SubExp)
-> VName
forall b c a. (b -> c) -> (a -> b) -> a -> c
. (FParam rep, SubExp) -> FParam rep
forall a b. (a, b) -> a
fst) [(FParam rep, SubExp)]
merge) [Bool]
pat_used
    usedAfterLoop :: Param dec -> Bool
usedAfterLoop = (VName -> [VName] -> Bool) -> [VName] -> VName -> Bool
forall a b c. (a -> b -> c) -> b -> a -> c
flip VName -> [VName] -> Bool
forall (t :: * -> *) a. (Foldable t, Eq a) => a -> t a -> Bool
elem [VName]
used_vals (VName -> Bool) -> (Param dec -> VName) -> Param dec -> Bool
forall b c a. (b -> c) -> (a -> b) -> a -> c
. Param dec -> VName
forall dec. Param dec -> VName
paramName
    usedAfterLoopOrInForm :: Param dec -> Bool
usedAfterLoopOrInForm Param dec
p =
      Param dec -> Bool
forall dec. Param dec -> Bool
usedAfterLoop Param dec
p Bool -> Bool -> Bool
|| Param dec -> VName
forall dec. Param dec -> VName
paramName Param dec
p VName -> Names -> Bool
`nameIn` LoopForm rep -> Names
forall a. FreeIn a => a -> Names
freeIn LoopForm rep
form
    patAnnotNames :: Names
patAnnotNames = [FParam rep] -> Names
forall a. FreeIn a => a -> Names
freeIn ([FParam rep] -> Names) -> [FParam rep] -> Names
forall a b. (a -> b) -> a -> b
$ ((FParam rep, SubExp) -> FParam rep)
-> [(FParam rep, SubExp)] -> [FParam rep]
forall a b. (a -> b) -> [a] -> [b]
map (FParam rep, SubExp) -> FParam rep
forall a b. (a, b) -> a
fst [(FParam rep, SubExp)]
merge
    referencedInPat :: Param dec -> Bool
referencedInPat = (VName -> Names -> Bool
`nameIn` Names
patAnnotNames) (VName -> Bool) -> (Param dec -> VName) -> Param dec -> Bool
forall b c a. (b -> c) -> (a -> b) -> a -> c
. Param dec -> VName
forall dec. Param dec -> VName
paramName
    referencedInForm :: Param dec -> Bool
referencedInForm = (VName -> Names -> Bool
`nameIn` LoopForm rep -> Names
forall a. FreeIn a => a -> Names
freeIn LoopForm rep
form) (VName -> Bool) -> (Param dec -> VName) -> Param dec -> Bool
forall b c a. (b -> c) -> (a -> b) -> a -> c
. Param dec -> VName
forall dec. Param dec -> VName
paramName

    dummyStms :: [((FParam rep, SubExp), b)] -> [([VName], Exp rep)]
dummyStms = (((FParam rep, SubExp), b) -> ([VName], Exp rep))
-> [((FParam rep, SubExp), b)] -> [([VName], Exp rep)]
forall a b. (a -> b) -> [a] -> [b]
map ((FParam rep, SubExp), b) -> ([VName], Exp rep)
forall dec b rep.
DeclTyped dec =>
((Param dec, SubExp), b) -> ([VName], Exp rep)
dummyStm
    dummyStm :: ((Param dec, SubExp), b) -> ([VName], Exp rep)
dummyStm ((Param dec
p, SubExp
e), b
_)
      | TypeBase Shape Uniqueness -> Bool
forall shape. TypeBase shape Uniqueness -> Bool
unique (Param dec -> TypeBase Shape Uniqueness
forall dec. DeclTyped dec => Param dec -> TypeBase Shape Uniqueness
paramDeclType Param dec
p),
        Var VName
v <- SubExp
e =
          ([Param dec -> VName
forall dec. Param dec -> VName
paramName Param dec
p], BasicOp -> Exp rep
forall rep. BasicOp -> Exp rep
BasicOp (BasicOp -> Exp rep) -> BasicOp -> Exp rep
forall a b. (a -> b) -> a -> b
$ VName -> BasicOp
Copy VName
v)
      | Bool
otherwise = ([Param dec -> VName
forall dec. Param dec -> VName
paramName Param dec
p], BasicOp -> Exp rep
forall rep. BasicOp -> Exp rep
BasicOp (BasicOp -> Exp rep) -> BasicOp -> Exp rep
forall a b. (a -> b) -> a -> b
$ SubExp -> BasicOp
SubExp SubExp
e)
removeRedundantMergeVariables (SymbolTable rep, UsageTable)
_ Pat (LetDec rep)
_ StmAux (ExpDec rep)
_ ([(FParam rep, SubExp)], LoopForm rep, Body rep)
_ =
  Rule rep
forall rep. Rule rep
Skip

-- We may change the type of the loop if we hoist out a shape
-- annotation, in which case we also need to tweak the bound pattern.
hoistLoopInvariantMergeVariables :: BuilderOps rep => TopDownRuleDoLoop rep
hoistLoopInvariantMergeVariables :: TopDownRuleDoLoop rep
hoistLoopInvariantMergeVariables TopDown rep
vtable Pat (LetDec rep)
pat StmAux (ExpDec rep)
aux ([(FParam rep, SubExp)]
merge, LoopForm rep
form, Body rep
loopbody) = do
  -- Figure out which of the elements of loopresult are
  -- loop-invariant, and hoist them out.
  let explpat :: [(PatElem (LetDec rep), VName)]
explpat = [PatElem (LetDec rep)]
-> [VName] -> [(PatElem (LetDec rep), VName)]
forall a b. [a] -> [b] -> [(a, b)]
zip (Pat (LetDec rep) -> [PatElem (LetDec rep)]
forall dec. Pat dec -> [PatElem dec]
patElems Pat (LetDec rep)
pat) ([VName] -> [(PatElem (LetDec rep), VName)])
-> [VName] -> [(PatElem (LetDec rep), VName)]
forall a b. (a -> b) -> a -> b
$ ((FParam rep, SubExp) -> VName)
-> [(FParam rep, SubExp)] -> [VName]
forall a b. (a -> b) -> [a] -> [b]
map (FParam rep -> VName
forall dec. Param dec -> VName
paramName (FParam rep -> VName)
-> ((FParam rep, SubExp) -> FParam rep)
-> (FParam rep, SubExp)
-> VName
forall b c a. (b -> c) -> (a -> b) -> a -> c
. (FParam rep, SubExp) -> FParam rep
forall a b. (a, b) -> a
fst) [(FParam rep, SubExp)]
merge
  case ((VName, (FParam rep, SubExp), SubExpRes)
 -> ([(Ident, SubExp)], [(PatElem (LetDec rep), VName)],
     [(FParam rep, SubExp)], [SubExpRes])
 -> ([(Ident, SubExp)], [(PatElem (LetDec rep), VName)],
     [(FParam rep, SubExp)], [SubExpRes]))
-> ([(Ident, SubExp)], [(PatElem (LetDec rep), VName)],
    [(FParam rep, SubExp)], [SubExpRes])
-> [(VName, (FParam rep, SubExp), SubExpRes)]
-> ([(Ident, SubExp)], [(PatElem (LetDec rep), VName)],
    [(FParam rep, SubExp)], [SubExpRes])
forall (t :: * -> *) a b.
Foldable t =>
(a -> b -> b) -> b -> t a -> b
foldr (VName, (FParam rep, SubExp), SubExpRes)
-> ([(Ident, SubExp)], [(PatElem (LetDec rep), VName)],
    [(FParam rep, SubExp)], [SubExpRes])
-> ([(Ident, SubExp)], [(PatElem (LetDec rep), VName)],
    [(FParam rep, SubExp)], [SubExpRes])
forall dec dec.
(Typed dec, FreeIn dec, Typed dec) =>
(VName, (Param dec, SubExp), SubExpRes)
-> ([(Ident, SubExp)], [(PatElem dec, VName)],
    [(Param dec, SubExp)], [SubExpRes])
-> ([(Ident, SubExp)], [(PatElem dec, VName)],
    [(Param dec, SubExp)], [SubExpRes])
checkInvariance ([], [(PatElem (LetDec rep), VName)]
explpat, [], []) ([(VName, (FParam rep, SubExp), SubExpRes)]
 -> ([(Ident, SubExp)], [(PatElem (LetDec rep), VName)],
     [(FParam rep, SubExp)], [SubExpRes]))
-> [(VName, (FParam rep, SubExp), SubExpRes)]
-> ([(Ident, SubExp)], [(PatElem (LetDec rep), VName)],
    [(FParam rep, SubExp)], [SubExpRes])
forall a b. (a -> b) -> a -> b
$
    [VName]
-> [(FParam rep, SubExp)]
-> [SubExpRes]
-> [(VName, (FParam rep, SubExp), SubExpRes)]
forall a b c. [a] -> [b] -> [c] -> [(a, b, c)]
zip3 (Pat (LetDec rep) -> [VName]
forall dec. Pat dec -> [VName]
patNames Pat (LetDec rep)
pat) [(FParam rep, SubExp)]
merge [SubExpRes]
res of
    ([], [(PatElem (LetDec rep), VName)]
_, [(FParam rep, SubExp)]
_, [SubExpRes]
_) ->
      -- Nothing is invariant.
      Rule rep
forall rep. Rule rep
Skip
    ([(Ident, SubExp)]
invariant, [(PatElem (LetDec rep), VName)]
explpat', [(FParam rep, SubExp)]
merge', [SubExpRes]
res') -> RuleM rep () -> Rule rep
forall rep. RuleM rep () -> Rule rep
Simplify (RuleM rep () -> Rule rep) -> RuleM rep () -> Rule rep
forall a b. (a -> b) -> a -> b
$ do
      -- We have moved something invariant out of the loop.
      let loopbody' :: Body rep
loopbody' = Body rep
loopbody {bodyResult :: [SubExpRes]
bodyResult = [SubExpRes]
res'}
          explpat'' :: [PatElem (LetDec rep)]
explpat'' = ((PatElem (LetDec rep), VName) -> PatElem (LetDec rep))
-> [(PatElem (LetDec rep), VName)] -> [PatElem (LetDec rep)]
forall a b. (a -> b) -> [a] -> [b]
map (PatElem (LetDec rep), VName) -> PatElem (LetDec rep)
forall a b. (a, b) -> a
fst [(PatElem (LetDec rep), VName)]
explpat'
      [(Ident, SubExp)]
-> ((Ident, SubExp) -> RuleM rep ()) -> RuleM rep ()
forall (t :: * -> *) (m :: * -> *) a b.
(Foldable t, Monad m) =>
t a -> (a -> m b) -> m ()
forM_ [(Ident, SubExp)]
invariant (((Ident, SubExp) -> RuleM rep ()) -> RuleM rep ())
-> ((Ident, SubExp) -> RuleM rep ()) -> RuleM rep ()
forall a b. (a -> b) -> a -> b
$ \(Ident
v1, SubExp
v2) ->
        [VName] -> Exp (Rep (RuleM rep)) -> RuleM rep ()
forall (m :: * -> *).
MonadBuilder m =>
[VName] -> Exp (Rep m) -> m ()
letBindNames [Ident -> VName
identName Ident
v1] (Exp (Rep (RuleM rep)) -> RuleM rep ())
-> Exp (Rep (RuleM rep)) -> RuleM rep ()
forall a b. (a -> b) -> a -> b
$ BasicOp -> Exp rep
forall rep. BasicOp -> Exp rep
BasicOp (BasicOp -> Exp rep) -> BasicOp -> Exp rep
forall a b. (a -> b) -> a -> b
$ SubExp -> BasicOp
SubExp SubExp
v2
      StmAux (ExpDec rep) -> RuleM rep () -> RuleM rep ()
forall (m :: * -> *) anyrep a.
MonadBuilder m =>
StmAux anyrep -> m a -> m a
auxing StmAux (ExpDec rep)
aux (RuleM rep () -> RuleM rep ()) -> RuleM rep () -> RuleM rep ()
forall a b. (a -> b) -> a -> b
$ Pat (LetDec (Rep (RuleM rep)))
-> Exp (Rep (RuleM rep)) -> RuleM rep ()
forall (m :: * -> *).
MonadBuilder m =>
Pat (LetDec (Rep m)) -> Exp (Rep m) -> m ()
letBind ([PatElem (LetDec rep)] -> Pat (LetDec rep)
forall dec. [PatElem dec] -> Pat dec
Pat [PatElem (LetDec rep)]
explpat'') (Exp (Rep (RuleM rep)) -> RuleM rep ())
-> Exp (Rep (RuleM rep)) -> RuleM rep ()
forall a b. (a -> b) -> a -> b
$ [(FParam rep, SubExp)] -> LoopForm rep -> Body rep -> Exp rep
forall rep.
[(FParam rep, SubExp)] -> LoopForm rep -> Body rep -> Exp rep
DoLoop [(FParam rep, SubExp)]
merge' LoopForm rep
form Body rep
loopbody'
  where
    res :: [SubExpRes]
res = Body rep -> [SubExpRes]
forall rep. Body rep -> [SubExpRes]
bodyResult Body rep
loopbody

    namesOfMergeParams :: Names
namesOfMergeParams = [VName] -> Names
namesFromList ([VName] -> Names) -> [VName] -> Names
forall a b. (a -> b) -> a -> b
$ ((FParam rep, SubExp) -> VName)
-> [(FParam rep, SubExp)] -> [VName]
forall a b. (a -> b) -> [a] -> [b]
map (FParam rep -> VName
forall dec. Param dec -> VName
paramName (FParam rep -> VName)
-> ((FParam rep, SubExp) -> FParam rep)
-> (FParam rep, SubExp)
-> VName
forall b c a. (b -> c) -> (a -> b) -> a -> c
. (FParam rep, SubExp) -> FParam rep
forall a b. (a, b) -> a
fst) [(FParam rep, SubExp)]
merge

    removeFromResult :: (Param dec, b)
-> [(PatElem dec, VName)]
-> (Maybe (Ident, b), [(PatElem dec, VName)])
removeFromResult (Param dec
mergeParam, b
mergeInit) [(PatElem dec, VName)]
explpat' =
      case ((PatElem dec, VName) -> Bool)
-> [(PatElem dec, VName)]
-> ([(PatElem dec, VName)], [(PatElem dec, VName)])
forall a. (a -> Bool) -> [a] -> ([a], [a])
partition ((VName -> VName -> Bool
forall a. Eq a => a -> a -> Bool
== Param dec -> VName
forall dec. Param dec -> VName
paramName Param dec
mergeParam) (VName -> Bool)
-> ((PatElem dec, VName) -> VName) -> (PatElem dec, VName) -> Bool
forall b c a. (b -> c) -> (a -> b) -> a -> c
. (PatElem dec, VName) -> VName
forall a b. (a, b) -> b
snd) [(PatElem dec, VName)]
explpat' of
        ([(PatElem dec
patelem, VName
_)], [(PatElem dec, VName)]
rest) ->
          ((Ident, b) -> Maybe (Ident, b)
forall a. a -> Maybe a
Just (PatElem dec -> Ident
forall dec. Typed dec => PatElem dec -> Ident
patElemIdent PatElem dec
patelem, b
mergeInit), [(PatElem dec, VName)]
rest)
        ([(PatElem dec, VName)]
_, [(PatElem dec, VName)]
_) ->
          (Maybe (Ident, b)
forall a. Maybe a
Nothing, [(PatElem dec, VName)]
explpat')

    checkInvariance :: (VName, (Param dec, SubExp), SubExpRes)
-> ([(Ident, SubExp)], [(PatElem dec, VName)],
    [(Param dec, SubExp)], [SubExpRes])
-> ([(Ident, SubExp)], [(PatElem dec, VName)],
    [(Param dec, SubExp)], [SubExpRes])
checkInvariance
      (VName
pat_name, (Param dec
mergeParam, SubExp
mergeInit), SubExpRes
resExp)
      ([(Ident, SubExp)]
invariant, [(PatElem dec, VName)]
explpat', [(Param dec, SubExp)]
merge', [SubExpRes]
resExps)
        | Bool
isInvariant,
          -- Also do not remove the condition in a while-loop.
          Param dec -> VName
forall dec. Param dec -> VName
paramName Param dec
mergeParam VName -> Names -> Bool
`notNameIn` LoopForm rep -> Names
forall a. FreeIn a => a -> Names
freeIn LoopForm rep
form =
            let (Maybe (Ident, SubExp)
stm, [(PatElem dec, VName)]
explpat'') =
                  (Param dec, SubExp)
-> [(PatElem dec, VName)]
-> (Maybe (Ident, SubExp), [(PatElem dec, VName)])
forall dec dec b.
Typed dec =>
(Param dec, b)
-> [(PatElem dec, VName)]
-> (Maybe (Ident, b), [(PatElem dec, VName)])
removeFromResult (Param dec
mergeParam, SubExp
mergeInit) [(PatElem dec, VName)]
explpat'
             in ( ([(Ident, SubExp)] -> [(Ident, SubExp)])
-> ((Ident, SubExp) -> [(Ident, SubExp)] -> [(Ident, SubExp)])
-> Maybe (Ident, SubExp)
-> [(Ident, SubExp)]
-> [(Ident, SubExp)]
forall b a. b -> (a -> b) -> Maybe a -> b
maybe [(Ident, SubExp)] -> [(Ident, SubExp)]
forall a. a -> a
id (:) Maybe (Ident, SubExp)
stm ([(Ident, SubExp)] -> [(Ident, SubExp)])
-> [(Ident, SubExp)] -> [(Ident, SubExp)]
forall a b. (a -> b) -> a -> b
$ (Param dec -> Ident
forall dec. Typed dec => Param dec -> Ident
paramIdent Param dec
mergeParam, SubExp
mergeInit) (Ident, SubExp) -> [(Ident, SubExp)] -> [(Ident, SubExp)]
forall a. a -> [a] -> [a]
: [(Ident, SubExp)]
invariant,
                  [(PatElem dec, VName)]
explpat'',
                  [(Param dec, SubExp)]
merge',
                  [SubExpRes]
resExps
                )
        where
          -- A non-unique merge variable is invariant if one of the
          -- following is true:
          isInvariant :: Bool
isInvariant
            -- (0) The result is a variable of the same name as the
            -- parameter, where all existential parameters are already
            -- known to be invariant
            | Var VName
v2 <- SubExpRes -> SubExp
resSubExp SubExpRes
resExp,
              Param dec -> VName
forall dec. Param dec -> VName
paramName Param dec
mergeParam VName -> VName -> Bool
forall a. Eq a => a -> a -> Bool
== VName
v2 =
                Names -> Param dec -> Bool
forall dec. FreeIn dec => Names -> Param dec -> Bool
allExistentialInvariant
                  ([VName] -> Names
namesFromList ([VName] -> Names) -> [VName] -> Names
forall a b. (a -> b) -> a -> b
$ ((Ident, SubExp) -> VName) -> [(Ident, SubExp)] -> [VName]
forall a b. (a -> b) -> [a] -> [b]
map (Ident -> VName
identName (Ident -> VName)
-> ((Ident, SubExp) -> Ident) -> (Ident, SubExp) -> VName
forall b c a. (b -> c) -> (a -> b) -> a -> c
. (Ident, SubExp) -> Ident
forall a b. (a, b) -> a
fst) [(Ident, SubExp)]
invariant)
                  Param dec
mergeParam
            -- (1) The result is identical to the initial parameter value.
            | SubExp
mergeInit SubExp -> SubExp -> Bool
forall a. Eq a => a -> a -> Bool
== SubExpRes -> SubExp
resSubExp SubExpRes
resExp = Bool
True
            -- (2) The initial parameter value is equal to an outer
            -- loop parameter 'P', where the initial value of 'P' is
            -- equal to 'resExp', AND 'resExp' ultimately becomes the
            -- new value of 'P'.  XXX: it's a bit clumsy that this
            -- only works for one level of nesting, and I think it
            -- would not be too hard to generalise.
            | Var init_v <- SubExp
mergeInit,
              Just (SubExp
p_init, SubExp
p_res) <- VName -> TopDown rep -> Maybe (SubExp, SubExp)
forall rep. VName -> SymbolTable rep -> Maybe (SubExp, SubExp)
ST.lookupLoopParam VName
init_v TopDown rep
vtable,
              SubExp
p_init SubExp -> SubExp -> Bool
forall a. Eq a => a -> a -> Bool
== SubExpRes -> SubExp
resSubExp SubExpRes
resExp,
              SubExp
p_res SubExp -> SubExp -> Bool
forall a. Eq a => a -> a -> Bool
== VName -> SubExp
Var VName
pat_name =
                Bool
True
            | Bool
otherwise = Bool
False
    checkInvariance
      (VName
_pat_name, (Param dec
mergeParam, SubExp
mergeInit), SubExpRes
resExp)
      ([(Ident, SubExp)]
invariant, [(PatElem dec, VName)]
explpat', [(Param dec, SubExp)]
merge', [SubExpRes]
resExps) =
        ([(Ident, SubExp)]
invariant, [(PatElem dec, VName)]
explpat', (Param dec
mergeParam, SubExp
mergeInit) (Param dec, SubExp)
-> [(Param dec, SubExp)] -> [(Param dec, SubExp)]
forall a. a -> [a] -> [a]
: [(Param dec, SubExp)]
merge', SubExpRes
resExp SubExpRes -> [SubExpRes] -> [SubExpRes]
forall a. a -> [a] -> [a]
: [SubExpRes]
resExps)

    allExistentialInvariant :: Names -> Param dec -> Bool
allExistentialInvariant Names
namesOfInvariant Param dec
mergeParam =
      (VName -> Bool) -> [VName] -> Bool
forall (t :: * -> *) a. Foldable t => (a -> Bool) -> t a -> Bool
all (Names -> VName -> Bool
invariantOrNotMergeParam Names
namesOfInvariant) ([VName] -> Bool) -> [VName] -> Bool
forall a b. (a -> b) -> a -> b
$
        Names -> [VName]
namesToList (Names -> [VName]) -> Names -> [VName]
forall a b. (a -> b) -> a -> b
$
          Param dec -> Names
forall a. FreeIn a => a -> Names
freeIn Param dec
mergeParam Names -> Names -> Names
`namesSubtract` VName -> Names
oneName (Param dec -> VName
forall dec. Param dec -> VName
paramName Param dec
mergeParam)
    invariantOrNotMergeParam :: Names -> VName -> Bool
invariantOrNotMergeParam Names
namesOfInvariant VName
name =
      (VName
name VName -> Names -> Bool
`notNameIn` Names
namesOfMergeParams)
        Bool -> Bool -> Bool
|| (VName
name VName -> Names -> Bool
`nameIn` Names
namesOfInvariant)

simplifyClosedFormLoop :: BuilderOps rep => TopDownRuleDoLoop rep
simplifyClosedFormLoop :: TopDownRuleDoLoop rep
simplifyClosedFormLoop TopDown rep
_ Pat (LetDec rep)
pat StmAux (ExpDec rep)
_ ([(FParam rep, SubExp)]
val, ForLoop VName
i IntType
it SubExp
bound [], Body rep
body) =
  RuleM rep () -> Rule rep
forall rep. RuleM rep () -> Rule rep
Simplify (RuleM rep () -> Rule rep) -> RuleM rep () -> Rule rep
forall a b. (a -> b) -> a -> b
$ Pat (LetDec rep)
-> [(FParam rep, SubExp)]
-> Names
-> IntType
-> SubExp
-> Body rep
-> RuleM rep ()
forall rep.
(ASTRep rep, BuilderOps rep) =>
Pat (LetDec rep)
-> [(FParam rep, SubExp)]
-> Names
-> IntType
-> SubExp
-> Body rep
-> RuleM rep ()
loopClosedForm Pat (LetDec rep)
pat [(FParam rep, SubExp)]
val (VName -> Names
oneName VName
i) IntType
it SubExp
bound Body rep
body
simplifyClosedFormLoop TopDown rep
_ Pat (LetDec rep)
_ StmAux (ExpDec rep)
_ ([(FParam rep, SubExp)], LoopForm rep, Body rep)
_ = Rule rep
forall rep. Rule rep
Skip

simplifyLoopVariables :: (BuilderOps rep, Aliased rep) => TopDownRuleDoLoop rep
simplifyLoopVariables :: TopDownRuleDoLoop rep
simplifyLoopVariables TopDown rep
vtable Pat (LetDec rep)
pat StmAux (ExpDec rep)
aux ([(FParam rep, SubExp)]
merge, form :: LoopForm rep
form@(ForLoop VName
i IntType
it SubExp
num_iters [(LParam rep, VName)]
loop_vars), Body rep
body)
  | [Maybe (RuleM rep IndexResult)]
simplifiable <- ((LParam rep, VName) -> Maybe (RuleM rep IndexResult))
-> [(LParam rep, VName)] -> [Maybe (RuleM rep IndexResult)]
forall a b. (a -> b) -> [a] -> [b]
map (LParam rep, VName) -> Maybe (RuleM rep IndexResult)
forall dec.
Typed dec =>
(Param dec, VName) -> Maybe (RuleM rep IndexResult)
checkIfSimplifiable [(LParam rep, VName)]
loop_vars,
    Bool -> Bool
not (Bool -> Bool) -> Bool -> Bool
forall a b. (a -> b) -> a -> b
$ (Maybe (RuleM rep IndexResult) -> Bool)
-> [Maybe (RuleM rep IndexResult)] -> Bool
forall (t :: * -> *) a. Foldable t => (a -> Bool) -> t a -> Bool
all Maybe (RuleM rep IndexResult) -> Bool
forall a. Maybe a -> Bool
isNothing [Maybe (RuleM rep IndexResult)]
simplifiable = RuleM rep () -> Rule rep
forall rep. RuleM rep () -> Rule rep
Simplify (RuleM rep () -> Rule rep) -> RuleM rep () -> Rule rep
forall a b. (a -> b) -> a -> b
$ do
      -- Check if the simplifications throw away more information than
      -- we are comfortable with at this stage.
      ([Maybe (LParam rep, VName)]
maybe_loop_vars, [Stms rep]
body_prefix_stms) <-
        Scope rep
-> RuleM rep ([Maybe (LParam rep, VName)], [Stms rep])
-> RuleM rep ([Maybe (LParam rep, VName)], [Stms rep])
forall rep (m :: * -> *) a.
LocalScope rep m =>
Scope rep -> m a -> m a
localScope (LoopForm rep -> Scope rep
forall rep a. Scoped rep a => a -> Scope rep
scopeOf LoopForm rep
form) (RuleM rep ([Maybe (LParam rep, VName)], [Stms rep])
 -> RuleM rep ([Maybe (LParam rep, VName)], [Stms rep]))
-> RuleM rep ([Maybe (LParam rep, VName)], [Stms rep])
-> RuleM rep ([Maybe (LParam rep, VName)], [Stms rep])
forall a b. (a -> b) -> a -> b
$
          [(Maybe (LParam rep, VName), Stms rep)]
-> ([Maybe (LParam rep, VName)], [Stms rep])
forall a b. [(a, b)] -> ([a], [b])
unzip ([(Maybe (LParam rep, VName), Stms rep)]
 -> ([Maybe (LParam rep, VName)], [Stms rep]))
-> RuleM rep [(Maybe (LParam rep, VName), Stms rep)]
-> RuleM rep ([Maybe (LParam rep, VName)], [Stms rep])
forall (f :: * -> *) a b. Functor f => (a -> b) -> f a -> f b
<$> ((LParam rep, VName)
 -> Maybe (RuleM rep IndexResult)
 -> RuleM rep (Maybe (LParam rep, VName), Stms rep))
-> [(LParam rep, VName)]
-> [Maybe (RuleM rep IndexResult)]
-> RuleM rep [(Maybe (LParam rep, VName), Stms rep)]
forall (m :: * -> *) a b c.
Applicative m =>
(a -> b -> m c) -> [a] -> [b] -> m [c]
zipWithM (LParam rep, VName)
-> Maybe (RuleM rep IndexResult)
-> RuleM rep (Maybe (LParam rep, VName), Stms rep)
forall (f :: * -> *) dec.
MonadBuilder f =>
(Param dec, VName)
-> Maybe (f IndexResult)
-> f (Maybe (Param dec, VName), Stms (Rep f))
onLoopVar [(LParam rep, VName)]
loop_vars [Maybe (RuleM rep IndexResult)]
simplifiable
      if [Maybe (LParam rep, VName)]
maybe_loop_vars [Maybe (LParam rep, VName)] -> [Maybe (LParam rep, VName)] -> Bool
forall a. Eq a => a -> a -> Bool
== ((LParam rep, VName) -> Maybe (LParam rep, VName))
-> [(LParam rep, VName)] -> [Maybe (LParam rep, VName)]
forall a b. (a -> b) -> [a] -> [b]
map (LParam rep, VName) -> Maybe (LParam rep, VName)
forall a. a -> Maybe a
Just [(LParam rep, VName)]
loop_vars
        then RuleM rep ()
forall rep a. RuleM rep a
cannotSimplify
        else do
          Body rep
body' <- RuleM rep [SubExpRes] -> RuleM rep (Body (Rep (RuleM rep)))
forall (m :: * -> *).
MonadBuilder m =>
m [SubExpRes] -> m (Body (Rep m))
buildBody_ (RuleM rep [SubExpRes] -> RuleM rep (Body (Rep (RuleM rep))))
-> RuleM rep [SubExpRes] -> RuleM rep (Body (Rep (RuleM rep)))
forall a b. (a -> b) -> a -> b
$ do
            Stms (Rep (RuleM rep)) -> RuleM rep ()
forall (m :: * -> *). MonadBuilder m => Stms (Rep m) -> m ()
addStms (Stms (Rep (RuleM rep)) -> RuleM rep ())
-> Stms (Rep (RuleM rep)) -> RuleM rep ()
forall a b. (a -> b) -> a -> b
$ [Stms rep] -> Stms rep
forall a. Monoid a => [a] -> a
mconcat [Stms rep]
body_prefix_stms
            Body (Rep (RuleM rep)) -> RuleM rep [SubExpRes]
forall (m :: * -> *).
MonadBuilder m =>
Body (Rep m) -> m [SubExpRes]
bodyBind Body rep
Body (Rep (RuleM rep))
body
          let form' :: LoopForm rep
form' = VName -> IntType -> SubExp -> [(LParam rep, VName)] -> LoopForm rep
forall rep.
VName -> IntType -> SubExp -> [(LParam rep, VName)] -> LoopForm rep
ForLoop VName
i IntType
it SubExp
num_iters ([(LParam rep, VName)] -> LoopForm rep)
-> [(LParam rep, VName)] -> LoopForm rep
forall a b. (a -> b) -> a -> b
$ [Maybe (LParam rep, VName)] -> [(LParam rep, VName)]
forall a. [Maybe a] -> [a]
catMaybes [Maybe (LParam rep, VName)]
maybe_loop_vars
          StmAux (ExpDec rep) -> RuleM rep () -> RuleM rep ()
forall (m :: * -> *) anyrep a.
MonadBuilder m =>
StmAux anyrep -> m a -> m a
auxing StmAux (ExpDec rep)
aux (RuleM rep () -> RuleM rep ()) -> RuleM rep () -> RuleM rep ()
forall a b. (a -> b) -> a -> b
$ Pat (LetDec (Rep (RuleM rep)))
-> Exp (Rep (RuleM rep)) -> RuleM rep ()
forall (m :: * -> *).
MonadBuilder m =>
Pat (LetDec (Rep m)) -> Exp (Rep m) -> m ()
letBind Pat (LetDec rep)
Pat (LetDec (Rep (RuleM rep)))
pat (Exp (Rep (RuleM rep)) -> RuleM rep ())
-> Exp (Rep (RuleM rep)) -> RuleM rep ()
forall a b. (a -> b) -> a -> b
$ [(FParam rep, SubExp)] -> LoopForm rep -> Body rep -> Exp rep
forall rep.
[(FParam rep, SubExp)] -> LoopForm rep -> Body rep -> Exp rep
DoLoop [(FParam rep, SubExp)]
merge LoopForm rep
form' Body rep
body'
  where
    seType :: SubExp -> Maybe (TypeBase Shape NoUniqueness)
seType (Var VName
v)
      | VName
v VName -> VName -> Bool
forall a. Eq a => a -> a -> Bool
== VName
i = TypeBase Shape NoUniqueness -> Maybe (TypeBase Shape NoUniqueness)
forall a. a -> Maybe a
Just (TypeBase Shape NoUniqueness
 -> Maybe (TypeBase Shape NoUniqueness))
-> TypeBase Shape NoUniqueness
-> Maybe (TypeBase Shape NoUniqueness)
forall a b. (a -> b) -> a -> b
$ PrimType -> TypeBase Shape NoUniqueness
forall shape u. PrimType -> TypeBase shape u
Prim (PrimType -> TypeBase Shape NoUniqueness)
-> PrimType -> TypeBase Shape NoUniqueness
forall a b. (a -> b) -> a -> b
$ IntType -> PrimType
IntType IntType
it
      | Bool
otherwise = VName -> TopDown rep -> Maybe (TypeBase Shape NoUniqueness)
forall rep.
ASTRep rep =>
VName -> SymbolTable rep -> Maybe (TypeBase Shape NoUniqueness)
ST.lookupType VName
v TopDown rep
vtable
    seType (Constant PrimValue
v) = TypeBase Shape NoUniqueness -> Maybe (TypeBase Shape NoUniqueness)
forall a. a -> Maybe a
Just (TypeBase Shape NoUniqueness
 -> Maybe (TypeBase Shape NoUniqueness))
-> TypeBase Shape NoUniqueness
-> Maybe (TypeBase Shape NoUniqueness)
forall a b. (a -> b) -> a -> b
$ PrimType -> TypeBase Shape NoUniqueness
forall shape u. PrimType -> TypeBase shape u
Prim (PrimType -> TypeBase Shape NoUniqueness)
-> PrimType -> TypeBase Shape NoUniqueness
forall a b. (a -> b) -> a -> b
$ PrimValue -> PrimType
primValueType PrimValue
v
    consumed_in_body :: Names
consumed_in_body = Body rep -> Names
forall rep. Aliased rep => Body rep -> Names
consumedInBody Body rep
body

    vtable' :: TopDown rep
vtable' = Scope rep -> TopDown rep
forall rep. ASTRep rep => Scope rep -> SymbolTable rep
ST.fromScope (LoopForm rep -> Scope rep
forall rep a. Scoped rep a => a -> Scope rep
scopeOf LoopForm rep
form) TopDown rep -> TopDown rep -> TopDown rep
forall a. Semigroup a => a -> a -> a
<> TopDown rep
vtable

    checkIfSimplifiable :: (Param dec, VName) -> Maybe (RuleM rep IndexResult)
checkIfSimplifiable (Param dec
p, VName
arr) =
      SymbolTable (Rep (RuleM rep))
-> (SubExp -> Maybe (TypeBase Shape NoUniqueness))
-> VName
-> Slice SubExp
-> Bool
-> Maybe (RuleM rep IndexResult)
forall (m :: * -> *).
MonadBuilder m =>
SymbolTable (Rep m)
-> (SubExp -> Maybe (TypeBase Shape NoUniqueness))
-> VName
-> Slice SubExp
-> Bool
-> Maybe (m IndexResult)
simplifyIndexing
        TopDown rep
SymbolTable (Rep (RuleM rep))
vtable'
        SubExp -> Maybe (TypeBase Shape NoUniqueness)
seType
        VName
arr
        ([DimIndex SubExp] -> Slice SubExp
forall d. [DimIndex d] -> Slice d
Slice (SubExp -> DimIndex SubExp
forall d. d -> DimIndex d
DimFix (VName -> SubExp
Var VName
i) DimIndex SubExp -> [DimIndex SubExp] -> [DimIndex SubExp]
forall a. a -> [a] -> [a]
: Slice SubExp -> [DimIndex SubExp]
forall d. Slice d -> [DimIndex d]
unSlice (TypeBase Shape NoUniqueness -> [DimIndex SubExp] -> Slice SubExp
fullSlice (Param dec -> TypeBase Shape NoUniqueness
forall dec. Typed dec => Param dec -> TypeBase Shape NoUniqueness
paramType Param dec
p) [])))
        (Bool -> Maybe (RuleM rep IndexResult))
-> Bool -> Maybe (RuleM rep IndexResult)
forall a b. (a -> b) -> a -> b
$ Param dec -> VName
forall dec. Param dec -> VName
paramName Param dec
p VName -> Names -> Bool
`nameIn` Names
consumed_in_body

    -- We only want this simplification if the result does not refer
    -- to 'i' at all, or does not contain accesses.
    onLoopVar :: (Param dec, VName)
-> Maybe (f IndexResult)
-> f (Maybe (Param dec, VName), Stms (Rep f))
onLoopVar (Param dec
p, VName
arr) Maybe (f IndexResult)
Nothing =
      (Maybe (Param dec, VName), Stms (Rep f))
-> f (Maybe (Param dec, VName), Stms (Rep f))
forall (f :: * -> *) a. Applicative f => a -> f a
pure ((Param dec, VName) -> Maybe (Param dec, VName)
forall a. a -> Maybe a
Just (Param dec
p, VName
arr), Stms (Rep f)
forall a. Monoid a => a
mempty)
    onLoopVar (Param dec
p, VName
arr) (Just f IndexResult
m) = do
      (IndexResult
x, Stms (Rep f)
x_stms) <- f IndexResult -> f (IndexResult, Stms (Rep f))
forall (m :: * -> *) a.
MonadBuilder m =>
m a -> m (a, Stms (Rep m))
collectStms f IndexResult
m
      case IndexResult
x of
        IndexResult Certs
cs VName
arr' (Slice [DimIndex SubExp]
slice)
          | Bool -> Bool
not (Bool -> Bool) -> Bool -> Bool
forall a b. (a -> b) -> a -> b
$ (Stm (Rep f) -> Bool) -> Stms (Rep f) -> Bool
forall (t :: * -> *) a. Foldable t => (a -> Bool) -> t a -> Bool
any ((VName
i VName -> Names -> Bool
`nameIn`) (Names -> Bool) -> (Stm (Rep f) -> Names) -> Stm (Rep f) -> Bool
forall b c a. (b -> c) -> (a -> b) -> a -> c
. Stm (Rep f) -> Names
forall a. FreeIn a => a -> Names
freeIn) Stms (Rep f)
x_stms,
            DimFix (Var VName
j) : [DimIndex SubExp]
slice' <- [DimIndex SubExp]
slice,
            VName
j VName -> VName -> Bool
forall a. Eq a => a -> a -> Bool
== VName
i,
            VName
i VName -> Names -> Bool
`notNameIn` [DimIndex SubExp] -> Names
forall a. FreeIn a => a -> Names
freeIn [DimIndex SubExp]
slice -> do
              Stms (Rep f) -> f ()
forall (m :: * -> *). MonadBuilder m => Stms (Rep m) -> m ()
addStms Stms (Rep f)
x_stms
              SubExp
w <- Int -> TypeBase Shape NoUniqueness -> SubExp
forall u. Int -> TypeBase Shape u -> SubExp
arraySize Int
0 (TypeBase Shape NoUniqueness -> SubExp)
-> f (TypeBase Shape NoUniqueness) -> f SubExp
forall (f :: * -> *) a b. Functor f => (a -> b) -> f a -> f b
<$> VName -> f (TypeBase Shape NoUniqueness)
forall rep (m :: * -> *).
HasScope rep m =>
VName -> m (TypeBase Shape NoUniqueness)
lookupType VName
arr'
              VName
for_in_partial <-
                Certs -> f VName -> f VName
forall (m :: * -> *) a. MonadBuilder m => Certs -> m a -> m a
certifying Certs
cs (f VName -> f VName) -> f VName -> f VName
forall a b. (a -> b) -> a -> b
$
                  String -> Exp (Rep f) -> f VName
forall (m :: * -> *).
MonadBuilder m =>
String -> Exp (Rep m) -> m VName
letExp String
"for_in_partial" (Exp (Rep f) -> f VName)
-> ([DimIndex SubExp] -> Exp (Rep f))
-> [DimIndex SubExp]
-> f VName
forall b c a. (b -> c) -> (a -> b) -> a -> c
. BasicOp -> Exp (Rep f)
forall rep. BasicOp -> Exp rep
BasicOp (BasicOp -> Exp (Rep f))
-> ([DimIndex SubExp] -> BasicOp)
-> [DimIndex SubExp]
-> Exp (Rep f)
forall b c a. (b -> c) -> (a -> b) -> a -> c
. VName -> Slice SubExp -> BasicOp
Index VName
arr' (Slice SubExp -> BasicOp)
-> ([DimIndex SubExp] -> Slice SubExp)
-> [DimIndex SubExp]
-> BasicOp
forall b c a. (b -> c) -> (a -> b) -> a -> c
. [DimIndex SubExp] -> Slice SubExp
forall d. [DimIndex d] -> Slice d
Slice ([DimIndex SubExp] -> f VName) -> [DimIndex SubExp] -> f VName
forall a b. (a -> b) -> a -> b
$
                    SubExp -> SubExp -> SubExp -> DimIndex SubExp
forall d. d -> d -> d -> DimIndex d
DimSlice (IntType -> Integer -> SubExp
intConst IntType
Int64 Integer
0) SubExp
w (IntType -> Integer -> SubExp
intConst IntType
Int64 Integer
1) DimIndex SubExp -> [DimIndex SubExp] -> [DimIndex SubExp]
forall a. a -> [a] -> [a]
: [DimIndex SubExp]
slice'
              (Maybe (Param dec, VName), Stms (Rep f))
-> f (Maybe (Param dec, VName), Stms (Rep f))
forall (f :: * -> *) a. Applicative f => a -> f a
pure ((Param dec, VName) -> Maybe (Param dec, VName)
forall a. a -> Maybe a
Just (Param dec
p, VName
for_in_partial), Stms (Rep f)
forall a. Monoid a => a
mempty)
        SubExpResult Certs
cs SubExp
se
          | (Stm (Rep f) -> Bool) -> Stms (Rep f) -> Bool
forall (t :: * -> *) a. Foldable t => (a -> Bool) -> t a -> Bool
all (Exp (Rep f) -> Bool
forall rep. Exp rep -> Bool
notIndex (Exp (Rep f) -> Bool)
-> (Stm (Rep f) -> Exp (Rep f)) -> Stm (Rep f) -> Bool
forall b c a. (b -> c) -> (a -> b) -> a -> c
. Stm (Rep f) -> Exp (Rep f)
forall rep. Stm rep -> Exp rep
stmExp) Stms (Rep f)
x_stms -> do
              Stms (Rep f)
x_stms' <- f () -> f (Stms (Rep f))
forall (m :: * -> *) a. MonadBuilder m => m a -> m (Stms (Rep m))
collectStms_ (f () -> f (Stms (Rep f))) -> f () -> f (Stms (Rep f))
forall a b. (a -> b) -> a -> b
$
                Certs -> f () -> f ()
forall (m :: * -> *) a. MonadBuilder m => Certs -> m a -> m a
certifying Certs
cs (f () -> f ()) -> f () -> f ()
forall a b. (a -> b) -> a -> b
$ do
                  Stms (Rep f) -> f ()
forall (m :: * -> *). MonadBuilder m => Stms (Rep m) -> m ()
addStms Stms (Rep f)
x_stms
                  [VName] -> Exp (Rep f) -> f ()
forall (m :: * -> *).
MonadBuilder m =>
[VName] -> Exp (Rep m) -> m ()
letBindNames [Param dec -> VName
forall dec. Param dec -> VName
paramName Param dec
p] (Exp (Rep f) -> f ()) -> Exp (Rep f) -> f ()
forall a b. (a -> b) -> a -> b
$ BasicOp -> Exp (Rep f)
forall rep. BasicOp -> Exp rep
BasicOp (BasicOp -> Exp (Rep f)) -> BasicOp -> Exp (Rep f)
forall a b. (a -> b) -> a -> b
$ SubExp -> BasicOp
SubExp SubExp
se
              (Maybe (Param dec, VName), Stms (Rep f))
-> f (Maybe (Param dec, VName), Stms (Rep f))
forall (f :: * -> *) a. Applicative f => a -> f a
pure (Maybe (Param dec, VName)
forall a. Maybe a
Nothing, Stms (Rep f)
x_stms')
        IndexResult
_ -> (Maybe (Param dec, VName), Stms (Rep f))
-> f (Maybe (Param dec, VName), Stms (Rep f))
forall (f :: * -> *) a. Applicative f => a -> f a
pure ((Param dec, VName) -> Maybe (Param dec, VName)
forall a. a -> Maybe a
Just (Param dec
p, VName
arr), Stms (Rep f)
forall a. Monoid a => a
mempty)

    notIndex :: Exp rep -> Bool
notIndex (BasicOp Index {}) = Bool
False
    notIndex Exp rep
_ = Bool
True
simplifyLoopVariables TopDown rep
_ Pat (LetDec rep)
_ StmAux (ExpDec rep)
_ ([(FParam rep, SubExp)], LoopForm rep, Body rep)
_ = Rule rep
forall rep. Rule rep
Skip

-- If a for-loop with no loop variables has a counter of type Int64,
-- and the bound is just a constant or sign-extended integer of
-- smaller type, then change the loop to iterate over the smaller type
-- instead.  We then move the sign extension inside the loop instead.
-- This addresses loops of the form @for i in x..<y@ in the source
-- language.
narrowLoopType :: (BuilderOps rep) => TopDownRuleDoLoop rep
narrowLoopType :: TopDownRuleDoLoop rep
narrowLoopType TopDown rep
vtable Pat (LetDec rep)
pat StmAux (ExpDec rep)
aux ([(FParam rep, SubExp)]
merge, ForLoop VName
i IntType
Int64 SubExp
n [], Body rep
body)
  | Just (SubExp
n', IntType
it', Certs
cs) <- Maybe (SubExp, IntType, Certs)
smallerType =
      RuleM rep () -> Rule rep
forall rep. RuleM rep () -> Rule rep
Simplify (RuleM rep () -> Rule rep) -> RuleM rep () -> Rule rep
forall a b. (a -> b) -> a -> b
$ do
        VName
i' <- String -> RuleM rep VName
forall (m :: * -> *). MonadFreshNames m => String -> m VName
newVName (String -> RuleM rep VName) -> String -> RuleM rep VName
forall a b. (a -> b) -> a -> b
$ VName -> String
baseString VName
i
        let form' :: LoopForm rep
form' = VName -> IntType -> SubExp -> [(LParam rep, VName)] -> LoopForm rep
forall rep.
VName -> IntType -> SubExp -> [(LParam rep, VName)] -> LoopForm rep
ForLoop VName
i' IntType
it' SubExp
n' []
        Body rep
body' <- RuleM rep (Body rep) -> RuleM rep (Body rep)
forall (m :: * -> *).
MonadBuilder m =>
m (Body (Rep m)) -> m (Body (Rep m))
insertStmsM (RuleM rep (Body rep) -> RuleM rep (Body rep))
-> (RuleM rep (Body rep) -> RuleM rep (Body rep))
-> RuleM rep (Body rep)
-> RuleM rep (Body rep)
forall b c a. (b -> c) -> (a -> b) -> a -> c
. LoopForm rep -> RuleM rep (Body rep) -> RuleM rep (Body rep)
forall rep a (m :: * -> *) b.
(Scoped rep a, LocalScope rep m) =>
a -> m b -> m b
inScopeOf LoopForm rep
forall rep. LoopForm rep
form' (RuleM rep (Body rep) -> RuleM rep (Body rep))
-> RuleM rep (Body rep) -> RuleM rep (Body rep)
forall a b. (a -> b) -> a -> b
$ do
          [VName] -> Exp (Rep (RuleM rep)) -> RuleM rep ()
forall (m :: * -> *).
MonadBuilder m =>
[VName] -> Exp (Rep m) -> m ()
letBindNames [VName
i] (Exp (Rep (RuleM rep)) -> RuleM rep ())
-> Exp (Rep (RuleM rep)) -> RuleM rep ()
forall a b. (a -> b) -> a -> b
$ BasicOp -> Exp rep
forall rep. BasicOp -> Exp rep
BasicOp (BasicOp -> Exp rep) -> BasicOp -> Exp rep
forall a b. (a -> b) -> a -> b
$ ConvOp -> SubExp -> BasicOp
ConvOp (IntType -> IntType -> ConvOp
SExt IntType
it' IntType
Int64) (VName -> SubExp
Var VName
i')
          Body rep -> RuleM rep (Body rep)
forall (f :: * -> *) a. Applicative f => a -> f a
pure Body rep
body
        StmAux (ExpDec rep) -> RuleM rep () -> RuleM rep ()
forall (m :: * -> *) anyrep a.
MonadBuilder m =>
StmAux anyrep -> m a -> m a
auxing StmAux (ExpDec rep)
aux (RuleM rep () -> RuleM rep ()) -> RuleM rep () -> RuleM rep ()
forall a b. (a -> b) -> a -> b
$ Certs -> RuleM rep () -> RuleM rep ()
forall (m :: * -> *) a. MonadBuilder m => Certs -> m a -> m a
certifying Certs
cs (RuleM rep () -> RuleM rep ()) -> RuleM rep () -> RuleM rep ()
forall a b. (a -> b) -> a -> b
$ Pat (LetDec (Rep (RuleM rep)))
-> Exp (Rep (RuleM rep)) -> RuleM rep ()
forall (m :: * -> *).
MonadBuilder m =>
Pat (LetDec (Rep m)) -> Exp (Rep m) -> m ()
letBind Pat (LetDec rep)
Pat (LetDec (Rep (RuleM rep)))
pat (Exp (Rep (RuleM rep)) -> RuleM rep ())
-> Exp (Rep (RuleM rep)) -> RuleM rep ()
forall a b. (a -> b) -> a -> b
$ [(FParam rep, SubExp)] -> LoopForm rep -> Body rep -> Exp rep
forall rep.
[(FParam rep, SubExp)] -> LoopForm rep -> Body rep -> Exp rep
DoLoop [(FParam rep, SubExp)]
merge LoopForm rep
forall rep. LoopForm rep
form' Body rep
body'
  where
    smallerType :: Maybe (SubExp, IntType, Certs)
smallerType
      | Var VName
n' <- SubExp
n,
        Just (ConvOp (SExt IntType
it' IntType
_) SubExp
n'', Certs
cs) <- VName -> TopDown rep -> Maybe (BasicOp, Certs)
forall rep. VName -> SymbolTable rep -> Maybe (BasicOp, Certs)
ST.lookupBasicOp VName
n' TopDown rep
vtable =
          (SubExp, IntType, Certs) -> Maybe (SubExp, IntType, Certs)
forall a. a -> Maybe a
Just (SubExp
n'', IntType
it', Certs
cs)
      | Constant (IntValue (Int64Value Int64
n')) <- SubExp
n,
        Int64 -> Integer
forall a. Integral a => a -> Integer
toInteger Int64
n' Integer -> Integer -> Bool
forall a. Ord a => a -> a -> Bool
<= Int32 -> Integer
forall a. Integral a => a -> Integer
toInteger (Int32
forall a. Bounded a => a
maxBound :: Int32) =
          (SubExp, IntType, Certs) -> Maybe (SubExp, IntType, Certs)
forall a. a -> Maybe a
Just (IntType -> Integer -> SubExp
intConst IntType
Int32 (Int64 -> Integer
forall a. Integral a => a -> Integer
toInteger Int64
n'), IntType
Int32, Certs
forall a. Monoid a => a
mempty)
      | Bool
otherwise =
          Maybe (SubExp, IntType, Certs)
forall a. Maybe a
Nothing
narrowLoopType TopDown rep
_ Pat (LetDec rep)
_ StmAux (ExpDec rep)
_ ([(FParam rep, SubExp)], LoopForm rep, Body rep)
_ = Rule rep
forall rep. Rule rep
Skip

unroll ::
  BuilderOps rep =>
  Integer ->
  [(FParam rep, SubExpRes)] ->
  (VName, IntType, Integer) ->
  [(LParam rep, VName)] ->
  Body rep ->
  RuleM rep [SubExpRes]
unroll :: Integer
-> [(FParam rep, SubExpRes)]
-> (VName, IntType, Integer)
-> [(LParam rep, VName)]
-> Body rep
-> RuleM rep [SubExpRes]
unroll Integer
n [(FParam rep, SubExpRes)]
merge (VName
iv, IntType
it, Integer
i) [(LParam rep, VName)]
loop_vars Body rep
body
  | Integer
i Integer -> Integer -> Bool
forall a. Ord a => a -> a -> Bool
>= Integer
n =
      [SubExpRes] -> RuleM rep [SubExpRes]
forall (f :: * -> *) a. Applicative f => a -> f a
pure ([SubExpRes] -> RuleM rep [SubExpRes])
-> [SubExpRes] -> RuleM rep [SubExpRes]
forall a b. (a -> b) -> a -> b
$ ((FParam rep, SubExpRes) -> SubExpRes)
-> [(FParam rep, SubExpRes)] -> [SubExpRes]
forall a b. (a -> b) -> [a] -> [b]
map (FParam rep, SubExpRes) -> SubExpRes
forall a b. (a, b) -> b
snd [(FParam rep, SubExpRes)]
merge
  | Bool
otherwise = do
      Body rep
iter_body <- RuleM rep (Body (Rep (RuleM rep)))
-> RuleM rep (Body (Rep (RuleM rep)))
forall (m :: * -> *).
MonadBuilder m =>
m (Body (Rep m)) -> m (Body (Rep m))
insertStmsM (RuleM rep (Body (Rep (RuleM rep)))
 -> RuleM rep (Body (Rep (RuleM rep))))
-> RuleM rep (Body (Rep (RuleM rep)))
-> RuleM rep (Body (Rep (RuleM rep)))
forall a b. (a -> b) -> a -> b
$ do
        [(FParam rep, SubExpRes)]
-> ((FParam rep, SubExpRes) -> RuleM rep ()) -> RuleM rep ()
forall (t :: * -> *) (m :: * -> *) a b.
(Foldable t, Monad m) =>
t a -> (a -> m b) -> m ()
forM_ [(FParam rep, SubExpRes)]
merge (((FParam rep, SubExpRes) -> RuleM rep ()) -> RuleM rep ())
-> ((FParam rep, SubExpRes) -> RuleM rep ()) -> RuleM rep ()
forall a b. (a -> b) -> a -> b
$ \(FParam rep
mergevar, SubExpRes Certs
cs SubExp
mergeinit) ->
          Certs -> RuleM rep () -> RuleM rep ()
forall (m :: * -> *) a. MonadBuilder m => Certs -> m a -> m a
certifying Certs
cs (RuleM rep () -> RuleM rep ()) -> RuleM rep () -> RuleM rep ()
forall a b. (a -> b) -> a -> b
$ [VName] -> Exp (Rep (RuleM rep)) -> RuleM rep ()
forall (m :: * -> *).
MonadBuilder m =>
[VName] -> Exp (Rep m) -> m ()
letBindNames [FParam rep -> VName
forall dec. Param dec -> VName
paramName FParam rep
mergevar] (Exp (Rep (RuleM rep)) -> RuleM rep ())
-> Exp (Rep (RuleM rep)) -> RuleM rep ()
forall a b. (a -> b) -> a -> b
$ BasicOp -> Exp rep
forall rep. BasicOp -> Exp rep
BasicOp (BasicOp -> Exp rep) -> BasicOp -> Exp rep
forall a b. (a -> b) -> a -> b
$ SubExp -> BasicOp
SubExp SubExp
mergeinit

        [VName] -> Exp (Rep (RuleM rep)) -> RuleM rep ()
forall (m :: * -> *).
MonadBuilder m =>
[VName] -> Exp (Rep m) -> m ()
letBindNames [VName
iv] (Exp (Rep (RuleM rep)) -> RuleM rep ())
-> Exp (Rep (RuleM rep)) -> RuleM rep ()
forall a b. (a -> b) -> a -> b
$ BasicOp -> Exp rep
forall rep. BasicOp -> Exp rep
BasicOp (BasicOp -> Exp rep) -> BasicOp -> Exp rep
forall a b. (a -> b) -> a -> b
$ SubExp -> BasicOp
SubExp (SubExp -> BasicOp) -> SubExp -> BasicOp
forall a b. (a -> b) -> a -> b
$ IntType -> Integer -> SubExp
intConst IntType
it Integer
i

        [(LParam rep, VName)]
-> ((LParam rep, VName) -> RuleM rep ()) -> RuleM rep ()
forall (t :: * -> *) (m :: * -> *) a b.
(Foldable t, Monad m) =>
t a -> (a -> m b) -> m ()
forM_ [(LParam rep, VName)]
loop_vars (((LParam rep, VName) -> RuleM rep ()) -> RuleM rep ())
-> ((LParam rep, VName) -> RuleM rep ()) -> RuleM rep ()
forall a b. (a -> b) -> a -> b
$ \(LParam rep
p, VName
arr) ->
          [VName] -> Exp (Rep (RuleM rep)) -> RuleM rep ()
forall (m :: * -> *).
MonadBuilder m =>
[VName] -> Exp (Rep m) -> m ()
letBindNames [LParam rep -> VName
forall dec. Param dec -> VName
paramName LParam rep
p] (Exp rep -> RuleM rep ())
-> ([DimIndex SubExp] -> Exp rep)
-> [DimIndex SubExp]
-> RuleM rep ()
forall b c a. (b -> c) -> (a -> b) -> a -> c
. BasicOp -> Exp rep
forall rep. BasicOp -> Exp rep
BasicOp (BasicOp -> Exp rep)
-> ([DimIndex SubExp] -> BasicOp) -> [DimIndex SubExp] -> Exp rep
forall b c a. (b -> c) -> (a -> b) -> a -> c
. VName -> Slice SubExp -> BasicOp
Index VName
arr (Slice SubExp -> BasicOp)
-> ([DimIndex SubExp] -> Slice SubExp)
-> [DimIndex SubExp]
-> BasicOp
forall b c a. (b -> c) -> (a -> b) -> a -> c
. [DimIndex SubExp] -> Slice SubExp
forall d. [DimIndex d] -> Slice d
Slice ([DimIndex SubExp] -> RuleM rep ())
-> [DimIndex SubExp] -> RuleM rep ()
forall a b. (a -> b) -> a -> b
$
            SubExp -> DimIndex SubExp
forall d. d -> DimIndex d
DimFix (IntType -> Integer -> SubExp
intConst IntType
Int64 Integer
i) DimIndex SubExp -> [DimIndex SubExp] -> [DimIndex SubExp]
forall a. a -> [a] -> [a]
: Slice SubExp -> [DimIndex SubExp]
forall d. Slice d -> [DimIndex d]
unSlice (TypeBase Shape NoUniqueness -> [DimIndex SubExp] -> Slice SubExp
fullSlice (LParam rep -> TypeBase Shape NoUniqueness
forall dec. Typed dec => Param dec -> TypeBase Shape NoUniqueness
paramType LParam rep
p) [])

        -- Some of the sizes in the types here might be temporarily wrong
        -- until copy propagation fixes it up.
        Body rep -> RuleM rep (Body rep)
forall (f :: * -> *) a. Applicative f => a -> f a
pure Body rep
body

      Body rep
iter_body' <- Body rep -> RuleM rep (Body rep)
forall rep (m :: * -> *).
(Renameable rep, MonadFreshNames m) =>
Body rep -> m (Body rep)
renameBody Body rep
iter_body
      Stms (Rep (RuleM rep)) -> RuleM rep ()
forall (m :: * -> *). MonadBuilder m => Stms (Rep m) -> m ()
addStms (Stms (Rep (RuleM rep)) -> RuleM rep ())
-> Stms (Rep (RuleM rep)) -> RuleM rep ()
forall a b. (a -> b) -> a -> b
$ Body rep -> Stms rep
forall rep. Body rep -> Stms rep
bodyStms Body rep
iter_body'

      let merge' :: [(FParam rep, SubExpRes)]
merge' = [FParam rep] -> [SubExpRes] -> [(FParam rep, SubExpRes)]
forall a b. [a] -> [b] -> [(a, b)]
zip (((FParam rep, SubExpRes) -> FParam rep)
-> [(FParam rep, SubExpRes)] -> [FParam rep]
forall a b. (a -> b) -> [a] -> [b]
map (FParam rep, SubExpRes) -> FParam rep
forall a b. (a, b) -> a
fst [(FParam rep, SubExpRes)]
merge) ([SubExpRes] -> [(FParam rep, SubExpRes)])
-> [SubExpRes] -> [(FParam rep, SubExpRes)]
forall a b. (a -> b) -> a -> b
$ Body rep -> [SubExpRes]
forall rep. Body rep -> [SubExpRes]
bodyResult Body rep
iter_body'
      Integer
-> [(FParam rep, SubExpRes)]
-> (VName, IntType, Integer)
-> [(LParam rep, VName)]
-> Body rep
-> RuleM rep [SubExpRes]
forall rep.
BuilderOps rep =>
Integer
-> [(FParam rep, SubExpRes)]
-> (VName, IntType, Integer)
-> [(LParam rep, VName)]
-> Body rep
-> RuleM rep [SubExpRes]
unroll Integer
n [(FParam rep, SubExpRes)]
merge' (VName
iv, IntType
it, Integer
i Integer -> Integer -> Integer
forall a. Num a => a -> a -> a
+ Integer
1) [(LParam rep, VName)]
loop_vars Body rep
body

simplifyKnownIterationLoop :: BuilderOps rep => TopDownRuleDoLoop rep
simplifyKnownIterationLoop :: TopDownRuleDoLoop rep
simplifyKnownIterationLoop TopDown rep
_ Pat (LetDec rep)
pat StmAux (ExpDec rep)
aux ([(FParam rep, SubExp)]
merge, ForLoop VName
i IntType
it (Constant PrimValue
iters) [(LParam rep, VName)]
loop_vars, Body rep
body)
  | IntValue IntValue
n <- PrimValue
iters,
    IntValue -> Bool
zeroIshInt IntValue
n Bool -> Bool -> Bool
|| IntValue -> Bool
oneIshInt IntValue
n Bool -> Bool -> Bool
|| Attr
"unroll" Attr -> Attrs -> Bool
`inAttrs` StmAux (ExpDec rep) -> Attrs
forall dec. StmAux dec -> Attrs
stmAuxAttrs StmAux (ExpDec rep)
aux = RuleM rep () -> Rule rep
forall rep. RuleM rep () -> Rule rep
Simplify (RuleM rep () -> Rule rep) -> RuleM rep () -> Rule rep
forall a b. (a -> b) -> a -> b
$ do
      [SubExpRes]
res <- Integer
-> [(FParam rep, SubExpRes)]
-> (VName, IntType, Integer)
-> [(LParam rep, VName)]
-> Body rep
-> RuleM rep [SubExpRes]
forall rep.
BuilderOps rep =>
Integer
-> [(FParam rep, SubExpRes)]
-> (VName, IntType, Integer)
-> [(LParam rep, VName)]
-> Body rep
-> RuleM rep [SubExpRes]
unroll (IntValue -> Integer
forall int. Integral int => IntValue -> int
valueIntegral IntValue
n) (((FParam rep, SubExp) -> (FParam rep, SubExpRes))
-> [(FParam rep, SubExp)] -> [(FParam rep, SubExpRes)]
forall a b. (a -> b) -> [a] -> [b]
map ((SubExp -> SubExpRes)
-> (FParam rep, SubExp) -> (FParam rep, SubExpRes)
forall (p :: * -> * -> *) b c a.
Bifunctor p =>
(b -> c) -> p a b -> p a c
second SubExp -> SubExpRes
subExpRes) [(FParam rep, SubExp)]
merge) (VName
i, IntType
it, Integer
0) [(LParam rep, VName)]
loop_vars Body rep
body
      [(VName, SubExpRes)]
-> ((VName, SubExpRes) -> RuleM rep ()) -> RuleM rep ()
forall (t :: * -> *) (m :: * -> *) a b.
(Foldable t, Monad m) =>
t a -> (a -> m b) -> m ()
forM_ ([VName] -> [SubExpRes] -> [(VName, SubExpRes)]
forall a b. [a] -> [b] -> [(a, b)]
zip (Pat (LetDec rep) -> [VName]
forall dec. Pat dec -> [VName]
patNames Pat (LetDec rep)
pat) [SubExpRes]
res) (((VName, SubExpRes) -> RuleM rep ()) -> RuleM rep ())
-> ((VName, SubExpRes) -> RuleM rep ()) -> RuleM rep ()
forall a b. (a -> b) -> a -> b
$ \(VName
v, SubExpRes Certs
cs SubExp
se) ->
        Certs -> RuleM rep () -> RuleM rep ()
forall (m :: * -> *) a. MonadBuilder m => Certs -> m a -> m a
certifying Certs
cs (RuleM rep () -> RuleM rep ()) -> RuleM rep () -> RuleM rep ()
forall a b. (a -> b) -> a -> b
$ [VName] -> Exp (Rep (RuleM rep)) -> RuleM rep ()
forall (m :: * -> *).
MonadBuilder m =>
[VName] -> Exp (Rep m) -> m ()
letBindNames [VName
v] (Exp (Rep (RuleM rep)) -> RuleM rep ())
-> Exp (Rep (RuleM rep)) -> RuleM rep ()
forall a b. (a -> b) -> a -> b
$ BasicOp -> Exp rep
forall rep. BasicOp -> Exp rep
BasicOp (BasicOp -> Exp rep) -> BasicOp -> Exp rep
forall a b. (a -> b) -> a -> b
$ SubExp -> BasicOp
SubExp SubExp
se
simplifyKnownIterationLoop TopDown rep
_ Pat (LetDec rep)
_ StmAux (ExpDec rep)
_ ([(FParam rep, SubExp)], LoopForm rep, Body rep)
_ =
  Rule rep
forall rep. Rule rep
Skip

topDownRules :: (BuilderOps rep, Aliased rep) => [TopDownRule rep]
topDownRules :: [TopDownRule rep]
topDownRules =
  [ RuleDoLoop rep (TopDown rep) -> TopDownRule rep
forall rep a. RuleDoLoop rep a -> SimplificationRule rep a
RuleDoLoop RuleDoLoop rep (TopDown rep)
forall rep. BuilderOps rep => TopDownRuleDoLoop rep
hoistLoopInvariantMergeVariables,
    RuleDoLoop rep (TopDown rep) -> TopDownRule rep
forall rep a. RuleDoLoop rep a -> SimplificationRule rep a
RuleDoLoop RuleDoLoop rep (TopDown rep)
forall rep. BuilderOps rep => TopDownRuleDoLoop rep
simplifyClosedFormLoop,
    RuleDoLoop rep (TopDown rep) -> TopDownRule rep
forall rep a. RuleDoLoop rep a -> SimplificationRule rep a
RuleDoLoop RuleDoLoop rep (TopDown rep)
forall rep. BuilderOps rep => TopDownRuleDoLoop rep
simplifyKnownIterationLoop,
    RuleDoLoop rep (TopDown rep) -> TopDownRule rep
forall rep a. RuleDoLoop rep a -> SimplificationRule rep a
RuleDoLoop RuleDoLoop rep (TopDown rep)
forall rep. (BuilderOps rep, Aliased rep) => TopDownRuleDoLoop rep
simplifyLoopVariables,
    RuleDoLoop rep (TopDown rep) -> TopDownRule rep
forall rep a. RuleDoLoop rep a -> SimplificationRule rep a
RuleDoLoop RuleDoLoop rep (TopDown rep)
forall rep. BuilderOps rep => TopDownRuleDoLoop rep
narrowLoopType
  ]

bottomUpRules :: BuilderOps rep => [BottomUpRule rep]
bottomUpRules :: [BottomUpRule rep]
bottomUpRules =
  [ RuleDoLoop rep (BottomUp rep) -> BottomUpRule rep
forall rep a. RuleDoLoop rep a -> SimplificationRule rep a
RuleDoLoop RuleDoLoop rep (BottomUp rep)
forall rep. BuilderOps rep => BottomUpRuleDoLoop rep
removeRedundantMergeVariables
  ]

-- | Standard loop simplification rules.
loopRules :: (BuilderOps rep, Aliased rep) => RuleBook rep
loopRules :: RuleBook rep
loopRules = [TopDownRule rep] -> [BottomUpRule rep] -> RuleBook rep
forall m. [TopDownRule m] -> [BottomUpRule m] -> RuleBook m
ruleBook [TopDownRule rep]
forall rep. (BuilderOps rep, Aliased rep) => [TopDownRule rep]
topDownRules [BottomUpRule rep]
forall rep. BuilderOps rep => [BottomUpRule rep]
bottomUpRules