X-Git-Url: http://git.megacz.com/?a=blobdiff_plain;f=compiler%2FnativeGen%2FRegAllocColor.hs;h=fc62157b98bdee163036453f8070714b0d0d5cc5;hb=d5938fb228511bfdce45e148ea4906129692e67f;hp=271c1a5ebcdbb976369383557d9b491293002bd3;hpb=a12bf21a5e9c2b7888cd0ed0c60b9ec1e7295df1;p=ghc-hetmet.git

diff --git a/compiler/nativeGen/RegAllocColor.hs b/compiler/nativeGen/RegAllocColor.hs
index 271c1a5..fc62157 100644
--- a/compiler/nativeGen/RegAllocColor.hs
+++ b/compiler/nativeGen/RegAllocColor.hs
@@ -17,7 +17,9 @@ import qualified GraphColor	as Color
 import RegLiveness
 import RegSpill
 import RegSpillClean
+import RegSpillCost
 import RegAllocStats
+-- import RegCoalesce
 import MachRegs
 import MachInstrs
 import PprMach
@@ -70,7 +72,6 @@ regAlloc_spin dflags (spinCount :: Int) triv regsFree slotsFree debug_codeGraphs
 		, dopt Opt_D_dump_asm_stats dflags
 		, dopt Opt_D_dump_asm_conflicts dflags ]
 
-
 	-- check that we're not running off down the garden path.
 	when (spinCount > maxSpinCount)
 	 $ pprPanic "regAlloc_spin: max build/spill cycle count exceeded."
@@ -80,8 +81,20 @@ regAlloc_spin dflags (spinCount :: Int) triv regsFree slotsFree debug_codeGraphs
 						$ uniqSetToList $ unionManyUniqSets $ eltsUFM regsFree)
 		$$ text "slotsFree   = " <> ppr (sizeUniqSet slotsFree))
 
+
+	-- Brig's algorithm does reckless coalescing for all but the first allocation stage
+	--	Doing this seems to reduce the number of reg-reg moves, but at the cost-
+	--	of creating more spills. Probably better just to stick with conservative 
+	--	coalescing in Color.colorGraph for now.
+	--
+	{- code_coalesced1	<- if (spinCount > 0) 
+				then regCoalesce code
+				else return code -}
+
+	let code_coalesced1	= code
+
  	-- build a conflict graph from the code.
-	graph		<- {-# SCC "BuildGraph" #-} buildGraph code
+	graph		<- {-# SCC "BuildGraph" #-} buildGraph code_coalesced1
 
 	-- VERY IMPORTANT:
 	--	We really do want the graph to be fully evaluated _before_ we start coloring.
@@ -91,11 +104,13 @@ regAlloc_spin dflags (spinCount :: Int) triv regsFree slotsFree debug_codeGraphs
 	seqGraph graph `seq` return ()
 
 
-	-- build a map of how many instructions each reg lives for.
-	--	this is lazy, it won't be computed unless we need to spill
+	-- build a map of the cost of spilling each instruction
+	--	this will only actually be computed if we have to spill something.
+	let spillCosts	= foldl' plusSpillCostInfo zeroSpillCostInfo
+			$ map slurpSpillCostInfo code_coalesced1
 
-	let fmLife	= {-# SCC "LifetimeCount" #-} plusUFMs_C (\(r1, l1) (_, l2) -> (r1, l1 + l2))
-			$ map lifetimeCount code
+	-- the function to choose regs to leave uncolored
+	let spill	= chooseSpill spillCosts
 
 	-- record startup state
 	let stat1	=
@@ -103,12 +118,8 @@ regAlloc_spin dflags (spinCount :: Int) triv regsFree slotsFree debug_codeGraphs
 		 then	Just $ RegAllocStatsStart
 		 	{ raLiveCmm	= code
 			, raGraph	= graph
-			, raLifetimes	= fmLife }
+			, raSpillCosts	= spillCosts }
 		 else	Nothing
-
-
-	-- the function to choose regs to leave uncolored
-	let spill	= chooseSpill_maxLife fmLife
 	
 	-- try and color the graph 
 	let (graph_colored, rsSpill, rmCoalesce)
@@ -119,17 +130,17 @@ regAlloc_spin dflags (spinCount :: Int) triv regsFree slotsFree debug_codeGraphs
 
 	-- rewrite regs in the code that have been coalesced
 	let patchF reg	= case lookupUFM rmCoalesce reg of
-				Just reg'	-> reg'
+				Just reg'	-> patchF reg'
 				Nothing		-> reg
-	let code_coalesced
-			= map (patchEraseLive patchF) code
+	let code_coalesced2
+			= map (patchEraseLive patchF) code_coalesced1
 
 
 	-- see if we've found a coloring
 	if isEmptyUniqSet rsSpill
 	 then do
 		-- patch the registers using the info in the graph
-	 	let code_patched	= map (patchRegsFromGraph graph_colored) code_coalesced
+	 	let code_patched	= map (patchRegsFromGraph graph_colored) code_coalesced2
 
 		-- clean out unneeded SPILL/RELOADs
 		let code_spillclean	= map cleanSpills code_patched
@@ -163,10 +174,11 @@ regAlloc_spin dflags (spinCount :: Int) triv regsFree slotsFree debug_codeGraphs
 			, statList
 			, graph_colored)
 
+	 -- we couldn't find a coloring, time to spill something
 	 else do
 	 	-- spill the uncolored regs
 		(code_spilled, slotsFree', spillStats)
-			<- regSpill code_coalesced slotsFree rsSpill
+			<- regSpill code_coalesced2 slotsFree rsSpill
 
 		-- recalculate liveness
 		let code_nat	= map stripLive code_spilled
@@ -178,7 +190,7 @@ regAlloc_spin dflags (spinCount :: Int) triv regsFree slotsFree debug_codeGraphs
 			{ raGraph	= graph_colored
 			, raCoalesced	= rmCoalesce
 			, raSpillStats	= spillStats
-			, raLifetimes	= fmLife
+			, raSpillCosts	= spillCosts
 			, raSpilled	= code_spilled }
 			    	
 		let statList =
@@ -193,46 +205,7 @@ regAlloc_spin dflags (spinCount :: Int) triv regsFree slotsFree debug_codeGraphs
 			statList
 			code_relive
 
- 
------
--- Simple maxconflicts isn't always good, because we
---	can naievely end up spilling vregs that only live for one or two instrs.
---	
-{-
-chooseSpill_maxConflicts
-	:: Color.Graph Reg RegClass Reg
-	-> Reg
-	
-chooseSpill_maxConflicts graph
- = let	node	= maximumBy 
- 			(\n1 n2 -> compare 
- 				(sizeUniqSet $ Color.nodeConflicts n1) 
-				(sizeUniqSet $ Color.nodeConflicts n2))
- 		$ eltsUFM $ Color.graphMap graph
-		
-   in	Color.nodeId node
--} 
-   
------
-chooseSpill_maxLife
-	:: UniqFM (Reg, Int)
-	-> Color.Graph Reg RegClass Reg
-	-> Reg
 
-chooseSpill_maxLife life graph
- = let	node	= maximumBy (\n1 n2 -> compare (getLife n1) (getLife n2))
-		$ eltsUFM $ Color.graphMap graph
-
-	-- Orphan vregs die in the same instruction they are born in.
-	--	They will be in the graph, but not in the liveness map.
-	--	Their liveness is 0.
-	getLife n
-	 = case lookupUFM life (Color.nodeId n) of
-	 	Just (_, l)	-> l
-		Nothing		-> 0
-
-   in	Color.nodeId node
-   
 
 -- | Build a graph from the liveness and coalesce information in this code.
 
@@ -246,13 +219,15 @@ buildGraph code
 	let (conflictList, moveList) =
 		unzip $ map slurpConflicts code
 
-	let conflictBag		= unionManyBags conflictList
-	let moveBag		= unionManyBags moveList
+	-- Slurp out the spill/reload coalesces
+	let moveList2		= map slurpReloadCoalesce code
 
  	-- Add the reg-reg conflicts to the graph
+	let conflictBag		= unionManyBags conflictList
 	let graph_conflict	= foldrBag graphAddConflictSet Color.initGraph conflictBag
 
 	-- Add the coalescences edges to the graph.
+	let moveBag		= unionBags (unionManyBags moveList2) (unionManyBags moveList)
 	let graph_coalesce	= foldrBag graphAddCoalesce graph_conflict moveBag
 			
 	return	graph_coalesce
@@ -326,15 +301,10 @@ patchRegsFromGraph graph code
 			(  text "There is no node in the graph for register " <> ppr reg
 			$$ ppr code
 			$$ Color.dotGraph (\_ -> text "white") trivColorable graph)
-	
+
    in	patchEraseLive patchF code
    
 
-plusUFMs_C  :: (elt -> elt -> elt) -> [UniqFM elt] -> UniqFM elt
-plusUFMs_C f maps
-	= foldl' (plusUFM_C f) emptyUFM maps
-
-
 -----
 -- for when laziness just isn't what you wanted...
 --