-- ** Substituting into expressions and related types
deShadowBinds, substSpec, substRulesForImportedIds,
substTy, substExpr, substBind, substUnfolding,
- substInlineRuleInfo, lookupIdSubst, lookupTvSubst, substIdOcc,
+ substUnfoldingSource, lookupIdSubst, lookupTvSubst, substIdOcc,
-- ** Operations on substitutions
emptySubst, mkEmptySubst, mkSubst, mkOpenSubst, substInScope, isEmptySubst,
import qualified Type
import Type ( Type, TvSubst(..), TvSubstEnv )
+import Coercion ( optCoercion )
import VarSet
import VarEnv
import Id
go (Lit lit) = Lit lit
go (App fun arg) = App (go fun) (go arg)
go (Note note e) = Note (go_note note) (go e)
- go (Cast e co) = Cast (go e) (substTy subst co)
+ go (Cast e co) = Cast (go e) (optCoercion (getTvSubst subst) co)
+ -- Optimise coercions as we go; this is good, for example
+ -- in the RHS of rules, which are only substituted in
+
go (Lam bndr body) = Lam bndr' (substExpr subst' body)
where
(subst', bndr') = substBndr subst bndr
-- | See 'Type.substTy'
substTy :: Subst -> Type -> Type
-substTy (Subst in_scope _id_env tv_env) ty
- = Type.substTy (TvSubst in_scope tv_env) ty
+substTy subst ty = Type.substTy (getTvSubst subst) ty
+
+getTvSubst :: Subst -> TvSubst
+getTvSubst (Subst in_scope _id_env tv_env) = TvSubst in_scope tv_env
\end{code}
substUnfolding subst (DFunUnfolding con args)
= DFunUnfolding con (map (substExpr subst) args)
-substUnfolding subst unf@(CoreUnfolding { uf_tmpl = tmpl, uf_guidance = guide@(InlineRule {}) })
+substUnfolding subst unf@(CoreUnfolding { uf_tmpl = tmpl, uf_src = src })
-- Retain an InlineRule!
+ | not (isInlineRuleSource src) -- Always zap a CoreUnfolding, to save substitution work
+ = NoUnfolding
+ | otherwise -- But keep an InlineRule!
= seqExpr new_tmpl `seq`
- new_info `seq`
- unf { uf_tmpl = new_tmpl, uf_guidance = guide { ir_info = new_info } }
+ new_src `seq`
+ unf { uf_tmpl = new_tmpl, uf_src = new_src }
where
new_tmpl = substExpr subst tmpl
- new_info = substInlineRuleInfo subst (ir_info guide)
-
-substUnfolding _ (CoreUnfolding {}) = NoUnfolding -- Discard
- -- Always zap a CoreUnfolding, to save substitution work
+ new_src = substUnfoldingSource subst src
substUnfolding _ unf = unf -- NoUnfolding, OtherCon
-------------------
-substInlineRuleInfo :: Subst -> InlineRuleInfo -> InlineRuleInfo
-substInlineRuleInfo (Subst in_scope ids _) (InlWrapper wkr)
- | Just (Var w1) <- lookupVarEnv ids wkr = InlWrapper w1
- | Just w1 <- lookupInScope in_scope wkr = InlWrapper w1
- | otherwise = WARN( True, text "Interesting! CoreSubst.substWorker:" <+> ppr wkr )
- InlVanilla -- Note [Worker inlining]
-substInlineRuleInfo _ info = info
+substUnfoldingSource :: Subst -> UnfoldingSource -> UnfoldingSource
+substUnfoldingSource (Subst in_scope ids _) (InlineWrapper wkr)
+ | Just wkr_expr <- lookupVarEnv ids wkr
+ = case wkr_expr of
+ Var w1 -> InlineWrapper w1
+ _other -> WARN( True, text "Interesting! CoreSubst.substWorker1:" <+> ppr wkr
+ <+> equals <+> ppr wkr_expr ) -- Note [Worker inlining]
+ InlineRule -- It's not a wrapper any more, but still inline it!
+
+ | Just w1 <- lookupInScope in_scope wkr = InlineWrapper w1
+ | otherwise = WARN( True, text "Interesting! CoreSubst.substWorker2:" <+> ppr wkr )
+ -- This can legitimately happen. The worker has been inlined and
+ -- dropped as dead code, because we don't treat the UnfoldingSource
+ -- as an "occurrence".
+ -- Note [Worker inlining]
+ InlineRule
+
+substUnfoldingSource _ src = src
------------------
substIdOcc :: Subst -> Id -> Id