unSaturatedOk, needSaturated, boringCxtOk, boringCxtNotOk,
-- ** Predicates and deconstruction on 'Unfolding'
- unfoldingTemplate, setUnfoldingTemplate,
+ unfoldingTemplate, setUnfoldingTemplate, expandUnfolding_maybe,
maybeUnfoldingTemplate, otherCons, unfoldingArity,
isValueUnfolding, isEvaldUnfolding, isCheapUnfolding,
isExpandableUnfolding, isConLikeUnfolding, isCompulsoryUnfolding,
-- See Note [INLINE for small functions] in CoreUnfold
ug_unsat_ok :: Bool, -- True <=> ok to inline even if unsaturated
ug_boring_ok :: Bool -- True <=> ok to inline even if the context is boring
+ -- So True,True means "always"
}
| UnfIfGoodArgs { -- Arose from a normal Id; the info here is the
isExpandableUnfolding (CoreUnfolding { uf_expandable = is_expable }) = is_expable
isExpandableUnfolding _ = False
+expandUnfolding_maybe :: Unfolding -> Maybe CoreExpr
+-- Expand an expandable unfolding; this is used in rule matching
+-- See Note [Expanding variables] in Rules.lhs
+-- The key point here is that CONLIKE things can be expanded
+expandUnfolding_maybe (CoreUnfolding { uf_expandable = True, uf_tmpl = rhs }) = Just rhs
+expandUnfolding_maybe _ = Nothing
+
isInlineRule :: Unfolding -> Bool
isInlineRule (CoreUnfolding { uf_src = src }) = isInlineRuleSource src
isInlineRule _ = False
isClosedUnfolding :: Unfolding -> Bool -- No free variables
isClosedUnfolding (CoreUnfolding {}) = False
+isClosedUnfolding (DFunUnfolding {}) = False
isClosedUnfolding _ = True
-- | Only returns False if there is no unfolding information available at all
you intend that calls (f e) are replaced by <rhs>[e/x] So we
should capture (\x.<rhs>) in the Unfolding of 'f', and never meddle
with it. Meanwhile, we can optimise <rhs> to our heart's content,
-leaving the original unfolding intact in Unfolding of 'f'.
+leaving the original unfolding intact in Unfolding of 'f'. For example
+ all xs = foldr (&&) True xs
+ any p = all . map p {-# INLINE any #-}
+We optimise any's RHS fully, but leave the InlineRule saying "all . map p",
+which deforests well at the call site.
-So the representation of an Unfolding has changed quite a bit
-(see CoreSyn). An INLINE pragma gives rise to an InlineRule
-unfolding.
+So INLINE pragma gives rise to an InlineRule, which captures the original RHS.
Moreover, it's only used when 'f' is applied to the
specified number of arguments; that is, the number of argument on