-- Invalidates any expressions that use a register.
invalidateUsersOf :: CmmReg -> AssignmentMap -> AssignmentMap
+-- foldUFM_Directly :: (Unique -> elt -> a -> a) -> a -> UniqFM elt -> a
+invalidateUsersOf reg m = foldUFM_Directly f m m -- [foldUFM performance]
+ where f u (xassign -> Just e) m | reg `regUsedIn` e = addToUFM_Directly m u NeverOptimize
+ f _ _ m = m
+{- This requires the entire spine of the map to be continually rebuilt,
+ - which causes crazy memory usage!
invalidateUsersOf reg = mapUFM (invalidateUsers' reg)
where invalidateUsers' reg (xassign -> Just e) | reg `regUsedIn` e = NeverOptimize
invalidateUsers' _ old = old
+-}
+
+-- Note [foldUFM performance]
+-- These calls to fold UFM no longer leak memory, but they do cause
+-- pretty killer amounts of allocation. So they'll be something to
+-- optimize; we need an algorithmic change to prevent us from having to
+-- traverse the /entire/ map continually.
middleAssignment :: WithRegUsage CmmNode O O -> AssignmentMap -> AssignmentMap
-- 2. Look for all assignments that load from memory locations that
-- were clobbered by this store and invalidate them.
middleAssignment (Plain n@(CmmStore lhs rhs)) assign
+ = let m = deleteSinks n assign
+ in foldUFM_Directly f m m -- [foldUFM performance]
+ where f u (xassign -> Just x) m | (lhs, rhs) `clobbers` (u, x) = addToUFM_Directly m u NeverOptimize
+ f _ _ m = m
+{- Also leaky
= mapUFM_Directly p . deleteSinks n $ assign
-- ToDo: There's a missed opportunity here: even if a memory
-- access we're attempting to sink gets clobbered at some
-- Unfortunately, it's too late to change the assignment...
where p r (xassign -> Just x) | (lhs, rhs) `clobbers` (r, x) = NeverOptimize
p _ old = old
+-}
-- Assumption: Unsafe foreign calls don't clobber memory
middleAssignment (Plain n@(CmmUnsafeForeignCall{})) assign
-- Variables are dead across calls, so invalidating all mappings is justified
lastAssignment (Plain (CmmCall _ (Just k) _ _ _)) assign = [(k, mapUFM (const NeverOptimize) assign)]
lastAssignment (Plain (CmmForeignCall {succ=k})) assign = [(k, mapUFM (const NeverOptimize) assign)]
-lastAssignment l assign = map (\id -> (id, assign)) $ successors l
+lastAssignment l assign = map (\id -> (id, deleteSinks l assign)) $ successors l
assignmentTransfer :: FwdTransfer (WithRegUsage CmmNode) AssignmentMap
assignmentTransfer = mkFTransfer3 (flip const) middleAssignment ((mkFactBase assignmentLattice .) . lastAssignment)