import RegLiveness
import RegSpill
import RegSpillClean
+import RegSpillCost
import RegAllocStats
+-- import RegCoalesce
import MachRegs
import MachInstrs
import PprMach
, 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."
$ 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.
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 =
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)
-- 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
-- strip off liveness information
- let code_nat = map stripLive code_patched
+ let code_nat = map stripLive code_spillclean
-- rewrite SPILL/RELOAD pseudos into real instructions
let spillNatTop = mapGenBlockTop spillNatBlock
, 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
{ raGraph = graph_colored
, raCoalesced = rmCoalesce
, raSpillStats = spillStats
- , raLifetimes = fmLife
+ , raSpillCosts = spillCosts
, raSpilled = code_spilled }
let statList =
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.
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
( 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...
--
projects / ghc-hetmet.git / blobdiff