X-Git-Url: http://git.megacz.com/?a=blobdiff_plain;f=compiler%2FnativeGen%2FGraphOps.hs;h=f620d8a0dfb5a266e5d4676388adbd353db7abd2;hb=16dc208aaad7aadaea970e47b8055d7d7f8781e5;hp=96c8e4e69f2a1509f7ac53e3ae1e4aa96387f44c;hpb=ad94d40948668032189ad22a0ad741ac1f645f50;p=ghc-hetmet.git

diff --git a/compiler/nativeGen/GraphOps.hs b/compiler/nativeGen/GraphOps.hs
index 96c8e4e..f620d8a 100644
--- a/compiler/nativeGen/GraphOps.hs
+++ b/compiler/nativeGen/GraphOps.hs
@@ -1,13 +1,6 @@
-
 -- | Basic operations on graphs.
 --
-
-{-# OPTIONS -w #-}
--- The above warning supression flag is a temporary kludge.
--- While working on this module you are encouraged to remove it and fix
--- any warnings in the module. See
---     http://hackage.haskell.org/trac/ghc/wiki/CodingStyle#Warnings
--- for details
+{-# OPTIONS -fno-warn-missing-signatures #-}
 
 module GraphOps (
 	addNode, 	delNode,	getNode,	lookupNode,	modNode,
@@ -275,10 +268,11 @@ addPreference (u, c) color
 --
 coalesceGraph
 	:: (Uniquable k, Ord k, Eq cls, Outputable k)
-	=>  Graph k cls color
+	=> Triv k cls color
+	-> Graph k cls color
 	-> (Graph k cls color, [(k, k)])
 
-coalesceGraph graph
+coalesceGraph triv graph
  = let
  	-- find all the nodes that have coalescence edges
 	cNodes	= filter (\node -> not $ isEmptyUniqSet (nodeCoalesce node))
@@ -297,7 +291,7 @@ coalesceGraph graph
 	-- do the coalescing, returning the new graph and a list of pairs of keys
 	--	that got coalesced together.
 	(graph', mPairs)
-		= mapAccumL coalesceNodes graph cList
+		= mapAccumL (coalesceNodes False triv) graph cList
 
    in	(graph', catMaybes mPairs)
 
@@ -312,32 +306,33 @@ coalesceGraph graph
 
 coalesceNodes
 	:: (Uniquable k, Ord k, Eq cls, Outputable k)
-	=> Graph k cls color
+	=> Bool			-- ^ If True, coalesce nodes even if this might make the graph
+				--	less colorable (aggressive coalescing)
+	-> Triv  k cls color
+	-> Graph k cls color
 	-> (k, k)		-- ^ keys of the nodes to be coalesced
 	-> (Graph k cls color, Maybe (k, k))
 
-coalesceNodes graph (k1, k2)
+coalesceNodes aggressive triv graph (k1, k2)
 	| (kMin, kMax)	<- if k1 < k2
 				then (k1, k2)
 				else (k2, k1)
 
-	-- nodes must be in the graph
-	, Just nMin	<- lookupNode graph kMin
-	, Just nMax	<- lookupNode graph kMax
+	-- the nodes being coalesced must be in the graph
+	, Just nMin		<- lookupNode graph kMin
+	, Just nMax		<- lookupNode graph kMax
 
-	-- can't coalesce conflicting nodes
+	-- can't coalesce conflicting modes
 	, not $ elementOfUniqSet kMin (nodeConflicts nMax)
 	, not $ elementOfUniqSet kMax (nodeConflicts nMin)
 
-	= coalesceNodes' graph kMin kMax nMin nMax
-
+	= coalesceNodes_merge aggressive triv graph kMin kMax nMin nMax
 
-
-	-- one of the nodes wasn't in the graph anymore
+	-- don't do the coalescing after all
 	| otherwise
 	= (graph, Nothing)
 
-coalesceNodes' graph kMin kMax nMin nMax
+coalesceNodes_merge aggressive triv graph kMin kMax nMin nMax
 
 	-- sanity checks
 	| nodeClass nMin /= nodeClass nMax
@@ -371,9 +366,20 @@ coalesceNodes' graph kMin kMax nMin nMax
 					`delOneFromUniqSet` kMax
 			}
 
-		-- delete the old nodes from the graph and add the new one
-	 	graph'	= addNode kMin node
-	  		$ delNode kMin
+	  in	coalesceNodes_check aggressive triv graph kMin kMax node
+
+coalesceNodes_check aggressive triv graph kMin kMax node
+
+	-- Unless we're coalescing aggressively, if the result node is not trivially
+	--	colorable then don't do the coalescing.
+	| not aggressive
+	, not $ triv (nodeClass node) (nodeConflicts node) (nodeExclusions node)
+	= (graph, Nothing)
+
+	| otherwise
+	= let -- delete the old nodes from the graph and add the new one
+		graph'	= addNode kMin node
+			$ delNode kMin
 			$ delNode kMax
 			$ graph
 
@@ -419,7 +425,7 @@ slurpNodeConflictCount
 
 slurpNodeConflictCount graph
 	= addListToUFM_C
-		(\(c1, n1) (c2, n2) -> (c1, n1 + n2))
+		(\(c1, n1) (_, n2) -> (c1, n1 + n2))
 		emptyUFM
 	$ map 	(\node
 	 	  -> let count	= sizeUniqSet $ nodeConflicts node
@@ -448,7 +454,7 @@ adjustWithDefaultUFM
 
 adjustWithDefaultUFM f def k map
 	= addToUFM_C 
-		(\old new -> f old)
+		(\old _ -> f old)
 		map
 		k def