UniqSupply
)
import FiniteMap
-import BasicTypes ( TopLevelFlag, isTopLevel,
+import BasicTypes ( TopLevelFlag, isTopLevel, isLoopBreaker,
Activation, isActive, isAlwaysActive,
OccInfo(..), isOneOcc
)
\begin{code}
postInlineUnconditionally :: SimplEnv -> OutId -> OccInfo -> OutExpr -> Bool
postInlineUnconditionally env bndr occ_info rhs
- = exprIsTrivial rhs && active && isOneOcc occ_info
- -- We used to have (not loop_breaker && not (isExportedId bndr))
- -- instead of (isOneOcc occ_info). Indeed, you might suppose that
+ = exprIsTrivial rhs
+ && active
+ && not (isLoopBreaker occ_info)
+ && not (isExportedId bndr)
+ -- We used to have (isOneOcc occ_info) instead of
+ -- not (isLoopBreaker occ_info) && not (isExportedId bndr)
+ -- That was because a rather fragile use of rules got confused
+ -- if you inlined even a binding f=g e.g. We used to have
+ -- map = mapList
+ -- But now a more precise use of phases has eliminated this problem,
+ -- so the is_active test will do the job. I think.
+ --
+ -- OLD COMMENT: (delete soon)
+ -- Indeed, you might suppose that
-- there is nothing wrong with substituting for a trivial RHS, even
-- if it occurs many times. But consider
-- x = y
-- h = _inline_me_ (...x...)
-- Here we do *not* want to have x inlined, even though the RHS is
-- trivial, becuase the contract for an INLINE pragma is "no inlining".
- -- This is important in the rules for the Prelude (e.g. PrelEnum.eftInt).
+ -- This is important in the rules for the Prelude
where
active = case getMode env of
SimplGently -> isAlwaysActive prag