SimplCont(..), DupFlag(..), LetRhsFlag(..),
contIsDupable, contResultType,
countValArgs, countArgs, pushContArgs,
- mkBoringStop, mkRhsStop, contIsRhs, contIsRhsOrArg,
- getContArgs, interestingCallContext, interestingArg, isStrictType
+ mkBoringStop, mkLazyArgStop, mkRhsStop, contIsRhs, contIsRhsOrArg,
+ getContArgs, interestingCallContext, interestingArgContext,
+ interestingArg, isStrictType
) where
opt_RulesOff )
import CoreSyn
import CoreFVs ( exprFreeVars )
-import CoreUtils ( cheapEqExpr, exprType, exprIsTrivial, exprIsCheap,
+import CoreUtils ( cheapEqExpr, exprType, exprIsTrivial,
etaExpand, exprEtaExpandArity, bindNonRec, mkCoerce2,
findDefault, exprOkForSpeculation, exprIsHNF, mergeAlts
)
import Literal ( mkStringLit )
import CoreUnfold ( smallEnoughToInline )
import MkId ( eRROR_ID )
-import Id ( idType, isDataConWorkId, idOccInfo, isDictId,
+import Id ( Id, idType, isDataConWorkId, idOccInfo, isDictId,
isDeadBinder, idNewDemandInfo, isExportedId,
- idUnfolding, idNewStrictness, idInlinePragma,
+ idUnfolding, idNewStrictness, idInlinePragma, idHasRules
)
import NewDemand ( isStrictDmd, isBotRes, splitStrictSig )
import SimplMonad
\begin{code}
data SimplCont -- Strict contexts
- = Stop OutType -- Type of the result
+ = Stop OutType -- Type of the result
LetRhsFlag
- Bool -- True <=> This is the RHS of a thunk whose type suggests
- -- that update-in-place would be possible
- -- (This makes the inliner a little keener.)
+ Bool -- True <=> There is something interesting about
+ -- the context, and hence the inliner
+ -- should be a bit keener (see interestingCallContext)
+ -- Two cases:
+ -- (a) This is the RHS of a thunk whose type suggests
+ -- that update-in-place would be possible
+ -- (b) This is an argument of a function that has RULES
+ -- Inlining the call might allow the rule to fire
| CoerceIt OutType -- The To-type, simplified
SimplCont
- | InlinePlease -- This continuation makes a function very
- SimplCont -- keen to inline itelf
-
| ApplyTo DupFlag
InExpr SimplEnv -- The argument, as yet unsimplified,
SimplCont -- and its environment
| ArgOf LetRhsFlag -- An arbitrary strict context: the argument
-- of a strict function, or a primitive-arg fn
-- or a PrimOp
- -- No DupFlag because we never duplicate it
+ -- No DupFlag, because we never duplicate it
OutType -- arg_ty: type of the argument itself
OutType -- cont_ty: the type of the expression being sought by the context
-- f (error "foo") ==> coerce t (error "foo")
ppr (Select dup bndr alts se cont) = (ptext SLIT("Select") <+> ppr dup <+> ppr bndr) $$
(nest 4 (ppr alts)) $$ ppr cont
ppr (CoerceIt ty cont) = (ptext SLIT("CoerceIt") <+> ppr ty) $$ ppr cont
- ppr (InlinePlease cont) = ptext SLIT("InlinePlease") $$ ppr cont
data DupFlag = OkToDup | NoDup
-------------------
-mkBoringStop, mkRhsStop :: OutType -> SimplCont
-mkBoringStop ty = Stop ty AnArg (canUpdateInPlace ty)
-mkRhsStop ty = Stop ty AnRhs (canUpdateInPlace ty)
+mkBoringStop :: OutType -> SimplCont
+mkBoringStop ty = Stop ty AnArg False
+
+mkLazyArgStop :: OutType -> Bool -> SimplCont
+mkLazyArgStop ty has_rules = Stop ty AnArg (canUpdateInPlace ty || has_rules)
+
+mkRhsStop :: OutType -> SimplCont
+mkRhsStop ty = Stop ty AnRhs (canUpdateInPlace ty)
contIsRhs :: SimplCont -> Bool
contIsRhs (Stop _ AnRhs _) = True
contIsDupable (ApplyTo OkToDup _ _ _) = True
contIsDupable (Select OkToDup _ _ _ _) = True
contIsDupable (CoerceIt _ cont) = contIsDupable cont
-contIsDupable (InlinePlease cont) = contIsDupable cont
contIsDupable other = False
-------------------
discardableCont :: SimplCont -> Bool
discardableCont (Stop _ _ _) = False
discardableCont (CoerceIt _ cont) = discardableCont cont
-discardableCont (InlinePlease cont) = discardableCont cont
discardableCont other = True
discardCont :: SimplCont -- A continuation, expecting
contResultType (ArgOf _ _ to_ty _) = to_ty
contResultType (ApplyTo _ _ _ cont) = contResultType cont
contResultType (CoerceIt _ cont) = contResultType cont
-contResultType (InlinePlease cont) = contResultType cont
contResultType (Select _ _ _ _ cont) = contResultType cont
-------------------
getContArgs :: SwitchChecker
-> OutId -> SimplCont
-> ([(InExpr, SimplEnv, Bool)], -- Arguments; the Bool is true for strict args
- SimplCont, -- Remaining continuation
- Bool) -- Whether we came across an InlineCall
+ SimplCont) -- Remaining continuation
-- getContArgs id k = (args, k', inl)
-- args are the leading ApplyTo items in k
-- (i.e. outermost comes first)
stricts | switchIsOn chkr NoCaseOfCase = vanilla_stricts
| otherwise = computed_stricts
in
- go [] stricts False orig_cont
+ go [] stricts orig_cont
where
----------------------------
-- Type argument
- go acc ss inl (ApplyTo _ arg@(Type _) se cont)
- = go ((arg,se,False) : acc) ss inl cont
+ go acc ss (ApplyTo _ arg@(Type _) se cont)
+ = go ((arg,se,False) : acc) ss cont
-- NB: don't bother to instantiate the function type
-- Value argument
- go acc (s:ss) inl (ApplyTo _ arg se cont)
- = go ((arg,se,s) : acc) ss inl cont
-
- -- An Inline continuation
- go acc ss inl (InlinePlease cont)
- = go acc ss True cont
+ go acc (s:ss) (ApplyTo _ arg se cont)
+ = go ((arg,se,s) : acc) ss cont
-- We're run out of arguments, or else we've run out of demands
-- The latter only happens if the result is guaranteed bottom
-- Then, especially in the first of these cases, we'd like to discard
-- the continuation, leaving just the bottoming expression. But the
-- type might not be right, so we may have to add a coerce.
- go acc ss inl cont
- | null ss && discardableCont cont = (reverse acc, discardCont cont, inl)
- | otherwise = (reverse acc, cont, inl)
+ go acc ss cont
+ | null ss && discardableCont cont = (reverse acc, discardCont cont)
+ | otherwise = (reverse acc, cont)
----------------------------
vanilla_stricts, computed_stricts :: [Bool]
interestingCallContext some_args some_val_args cont
= interesting cont
where
- interesting (InlinePlease _) = True
interesting (Select _ _ _ _ _) = some_args
interesting (ApplyTo _ _ _ _) = True -- Can happen if we have (coerce t (f x)) y
-- Perhaps True is a bit over-keen, but I've
-- seen (coerce f) x, where f has an INLINE prag,
-- So we have to give some motivaiton for inlining it
interesting (ArgOf _ _ _ _) = some_val_args
- interesting (Stop ty _ upd_in_place) = some_val_args && upd_in_place
+ interesting (Stop ty _ interesting) = some_val_args && interesting
interesting (CoerceIt _ cont) = interesting cont
-- If this call is the arg of a strict function, the context
-- is a bit interesting. If we inline here, we may get useful
-------------------
+interestingArgContext :: Id -> SimplCont -> Bool
+-- If the argument has form (f x y), where x,y are boring,
+-- and f is marked INLINE, then we don't want to inline f.
+-- But if the context of the argument is
+-- g (f x y)
+-- where g has rules, then we *do* want to inline f, in case it
+-- exposes a rule that might fire. Similarly, if the context is
+-- h (g (f x x))
+-- where h has rules, then we do want to inline f.
+-- The interesting_arg_ctxt flag makes this happen; if it's
+-- set, the inliner gets just enough keener to inline f
+-- regardless of how boring f's arguments are, if it's marked INLINE
+--
+-- The alternative would be to *always* inline an INLINE function,
+-- regardless of how boring its context is; but that seems overkill
+-- For example, it'd mean that wrapper functions were always inlined
+interestingArgContext fn cont
+ = idHasRules fn || go cont
+ where
+ go (Select {}) = False
+ go (ApplyTo {}) = False
+ go (ArgOf {}) = True
+ go (CoerceIt _ c) = go c
+ go (Stop _ _ interesting) = interesting
+
+-------------------
canUpdateInPlace :: Type -> Bool
-- Consider let x = <wurble> in ...
-- If <wurble> returns an explicit constructor, we might be able
==> ...(case x of I# x# -> case fw x# of ...)...
and now the redex (f x) isn't floatable any more.
-The no-inling thing is also important for Template Haskell. You might be
+The no-inlining thing is also important for Template Haskell. You might be
compiling in one-shot mode with -O2; but when TH compiles a splice before
running it, we don't want to use -O2. Indeed, we don't want to inline
anything, because the byte-code interpreter might get confused about
projects / ghc-hetmet.git / blobdiff