:: ( Uniquable k, Uniquable cls, Uniquable color
, Eq color, Eq cls, Ord k
, Outputable k, Outputable cls, Outputable color)
- => UniqFM (UniqSet color) -- ^ map of (node class -> set of colors available for this class).
+ => Bool -- ^ whether to do iterative coalescing
+ -> UniqFM (UniqSet color) -- ^ map of (node class -> set of colors available for this class).
-> Triv k cls color -- ^ fn to decide whether a node is trivially colorable.
-> (Graph k cls color -> k) -- ^ fn to choose a node to potentially leave uncolored if nothing is trivially colorable.
-> Graph k cls color -- ^ the graph to color.
, UniqFM k ) -- map of regs (r1 -> r2) that were coaleced
-- r1 should be replaced by r2 in the source
-colorGraph colors triv spill graph0
+colorGraph iterative colors triv spill graph0
= let
- -- do aggressive coalesing on the graph
- (graph_coalesced, rsCoalesce)
- = coalesceGraph triv graph0
+ -- if we're not doing iterative coalescing, then just do a single coalescing
+ -- pass at the front. This won't be as good but should still eat up a
+ -- lot of the reg-reg moves.
+ (graph_coalesced, kksCoalesce1)
+ = if not iterative
+ then coalesceGraph False triv graph0
+ else (graph0, [])
-- run the scanner to slurp out all the trivially colorable nodes
- (ksTriv, ksProblems)
- = colorScan triv spill graph_coalesced
+ -- (and do coalescing if iterative coalescing is enabled)
+ (ksTriv, ksProblems, kksCoalesce2)
+ = colorScan iterative triv spill graph_coalesced
+
+ -- If iterative coalescing is enabled, the scanner will coalesce the graph as does its business.
+ -- We need to apply all the coalescences found by the scanner to the original
+ -- graph before doing assignColors.
+ (graph_scan_coalesced, _)
+ = mapAccumL (coalesceNodes False triv) graph_coalesced kksCoalesce2
-- color the trivially colorable nodes
- -- as the keys were added to the front of the list while they were scanned,
- -- this colors them in the reverse order they were found, as required by the algorithm.
+ -- during scanning, keys of triv nodes were added to the front of the list as they were found
+ -- this colors them in the reverse order, as required by the algorithm.
(graph_triv, ksNoTriv)
- = assignColors colors graph_coalesced ksTriv
+ = assignColors colors graph_scan_coalesced ksTriv
-- try and color the problem nodes
- (graph_prob, ksNoColor) = assignColors colors graph_triv ksProblems
+ -- problem nodes are the ones that were left uncolored because they weren't triv.
+ -- theres a change we can color them here anyway.
+ (graph_prob, ksNoColor)
+ = assignColors colors graph_triv ksProblems
- -- if the trivially colorable nodes didn't color then something is wrong
+ -- if the trivially colorable nodes didn't color then something is probably wrong
-- with the provided triv function.
+ --
in if not $ null ksNoTriv
then pprPanic "colorGraph: trivially colorable nodes didn't color!" empty
{- ( empty
$$ dotGraph (\x -> text "white") triv graph1) -}
else ( graph_prob
- , mkUniqSet ksNoColor
- , listToUFM rsCoalesce)
+ , mkUniqSet ksNoColor -- the nodes that didn't color (spills)
+ , if iterative
+ then (listToUFM kksCoalesce2)
+ else (listToUFM kksCoalesce1))
-- | Scan through the conflict graph separating out trivially colorable and
-- at once the more likely it is that nodes we've already checked will become trivially colorable
-- for the next pass.
--
+-- TODO: add work lists to finding triv nodes is easier.
+-- If we've just scanned the graph, and removed triv nodes, then the only
+-- nodes that we need to rescan are the ones we've removed edges from.
+
colorScan
- :: ( Uniquable k, Uniquable cls, Uniquable color)
- => Triv k cls color -- ^ fn to decide whether a node is trivially colorable
+ :: ( Uniquable k, Uniquable cls, Uniquable color
+ , Ord k, Eq cls
+ , Outputable k, Outputable color)
+ => Bool -- ^ whether to do iterative coalescing
+ -> Triv k cls color -- ^ fn to decide whether a node is trivially colorable
-> (Graph k cls color -> k) -- ^ fn to choose a node to potentially leave uncolored if nothing is trivially colorable.
-> Graph k cls color -- ^ the graph to scan
- -> ([k], [k]) -- triv colorable, problem nodes
+ -> ([k], [k], [(k, k)]) -- triv colorable nodes, problem nodes, pairs of nodes to coalesce
-colorScan triv spill graph
- = colorScan' triv spill graph
- [] []
- []
- (eltsUFM $ graphMap graph)
+colorScan iterative triv spill graph
+ = colorScan_spin iterative triv spill graph [] [] []
--- we've reached the end of the candidates list
-colorScan' triv spill graph
- ksTriv ksTrivFound
- ksSpill
- []
+colorScan_spin iterative triv spill graph
+ ksTriv ksSpill kksCoalesce
-- if the graph is empty then we're done
| isNullUFM $ graphMap graph
- = (ksTrivFound ++ ksTriv, ksSpill)
-
- -- if we haven't found a trivially colorable node then we'll have to
- -- choose a spill candidate and leave it uncolored
- | [] <- ksTrivFound
- , kSpill <- spill graph -- choose a spill candiate
- , graph' <- delNode kSpill graph -- remove it from the graph
- , nsRest' <- eltsUFM $ graphMap graph' -- graph has changed, so get new node list
-
- = colorScan' triv spill graph'
- ksTriv ksTrivFound
- (kSpill : ksSpill)
- nsRest'
-
- -- we're at the end of the candidates list but we've found some triv nodes
- -- along the way. We can delete them from the graph and go back for more.
- | graph' <- foldr delNode graph ksTrivFound
- , nsRest' <- eltsUFM $ graphMap graph'
-
- = colorScan' triv spill graph'
- (ksTrivFound ++ ksTriv) []
- ksSpill
- nsRest'
-
--- check if the current node is triv colorable
-colorScan' triv spill graph
- ksTriv ksTrivFound
- ksSpill
- (node : nsRest)
-
- -- node is trivially colorable
- -- add it to the found nodes list and carry on.
- | k <- nodeId node
- , triv (nodeClass node) (nodeConflicts node) (nodeExclusions node)
-
- = colorScan' triv spill graph
- ksTriv (k : ksTrivFound)
+ = (ksTriv, ksSpill, kksCoalesce)
+
+ -- Simplify:
+ -- Look for trivially colorable nodes.
+ -- If we can find some then remove them from the graph and go back for more.
+ --
+ | nsTrivFound@(_:_)
+ <- scanGraph (\node -> triv (nodeClass node) (nodeConflicts node) (nodeExclusions node)
+
+ -- for iterative coalescing we only want non-move related
+ -- nodes here
+ && (not iterative || isEmptyUniqSet (nodeCoalesce node)))
+ $ graph
+
+ , ksTrivFound <- map nodeId nsTrivFound
+ , graph3 <- foldr delNode graph ksTrivFound
+ = colorScan_spin iterative triv spill graph3
+ (ksTrivFound ++ ksTriv)
ksSpill
- nsRest
-
- -- node wasn't trivially colorable, skip over it and look in the rest of the list
+ kksCoalesce
+
+ -- Coalesce:
+ -- If we're doing iterative coalescing and no triv nodes are avaliable
+ -- then it's type for a coalescing pass.
+ | iterative
+ = case coalesceGraph False triv graph of
+
+ -- we were able to coalesce something
+ -- go back and see if this frees up more nodes to be trivially colorable.
+ (graph2, kksCoalesceFound @(_:_))
+ -> colorScan_spin iterative triv spill graph2
+ ksTriv ksSpill (kksCoalesceFound ++ kksCoalesce)
+
+ -- Freeze:
+ -- nothing could be coalesced (or was triv),
+ -- time to choose a node to freeze and give up on ever coalescing it.
+ (graph2, [])
+ -> case freezeOneInGraph graph2 of
+
+ -- we were able to freeze something
+ -- hopefully this will free up something for Simplify
+ (graph3, True)
+ -> colorScan_spin iterative triv spill graph3
+ ksTriv ksSpill kksCoalesce
+
+ -- we couldn't find something to freeze either
+ -- time for a spill
+ (graph3, False)
+ -> colorScan_spill iterative triv spill graph3
+ ksTriv ksSpill kksCoalesce
+
+ -- spill time
| otherwise
- = colorScan' triv spill graph
- ksTriv ksTrivFound
- ksSpill
- nsRest
+ = colorScan_spill iterative triv spill graph
+ ksTriv ksSpill kksCoalesce
-{- -- This is cute and easy to understand, but too slow.. BL 2007/09
-colorScan colors triv spill safe prob graph
+-- Select:
+-- we couldn't find any triv nodes or things to freeze or coalesce,
+-- and the graph isn't empty yet.. We'll have to choose a spill
+-- candidate and leave it uncolored.
+--
+colorScan_spill iterative triv spill graph
+ ksTriv ksSpill kksCoalesce
- -- empty graphs are easy to color.
- | isNullUFM $ graphMap graph
- = (safe, prob)
-
- -- Try and find a trivially colorable node.
- | Just node <- find (\node -> triv (nodeClass node)
- (nodeConflicts node)
- (nodeExclusions node))
- $ eltsUFM $ graphMap graph
- , k <- nodeId node
- = colorScan colors triv spill
- (k : safe) prob (delNode k graph)
+ = let kSpill = spill graph
+ graph' = delNode kSpill graph
+ in colorScan_spin iterative triv spill graph'
+ ksTriv (kSpill : ksSpill) kksCoalesce
- -- There was no trivially colorable node,
- -- Choose one to potentially leave uncolored. We /might/ be able to find
- -- a color for this later on, but no guarantees.
- | k <- spill graph
- = colorScan colors triv spill
- safe (addOneToUniqSet prob k) (delNode k graph)
--}
-
-- | Try to assign a color to all these nodes.
projects / ghc-hetmet.git / blobdiff