{-# LANGUAGE BangPatterns #-} module RegAlloc.Graph.TrivColorable ( trivColorable, ) where #include "HsVersions.h" import RegClass import Reg import GraphBase import UniqFM import FastTypes import Platform import Panic -- trivColorable --------------------------------------------------------------- -- trivColorable function for the graph coloring allocator -- -- This gets hammered by scanGraph during register allocation, -- so needs to be fairly efficient. -- -- NOTE: This only works for arcitectures with just RcInteger and RcDouble -- (which are disjoint) ie. x86, x86_64 and ppc -- -- The number of allocatable regs is hard coded in here so we can do -- a fast comparision in trivColorable. -- -- It's ok if these numbers are _less_ than the actual number of free -- regs, but they can't be more or the register conflict -- graph won't color. -- -- If the graph doesn't color then the allocator will panic, but it won't -- generate bad object code or anything nasty like that. -- -- There is an allocatableRegsInClass :: RegClass -> Int, but doing -- the unboxing is too slow for us here. -- TODO: Is that still true? Could we use allocatableRegsInClass -- without losing performance now? -- -- Look at includes/stg/MachRegs.h to get the numbers. -- -- Disjoint registers ---------------------------------------------------------- -- -- The definition has been unfolded into individual cases for speed. -- Each architecture has a different register setup, so we use a -- different regSqueeze function for each. -- accSqueeze :: FastInt -> FastInt -> (reg -> FastInt) -> UniqFM reg -> FastInt accSqueeze count maxCount squeeze ufm = acc count (eltsUFM ufm) where acc count [] = count acc count _ | count >=# maxCount = count acc count (r:rs) = acc (count +# squeeze r) rs {- Note [accSqueeze] ~~~~~~~~~~~~~~~~~~~~ BL 2007/09 Doing a nice fold over the UniqSet makes trivColorable use 32% of total compile time and 42% of total alloc when compiling SHA1.lhs from darcs. Therefore the UniqFM is made non-abstract and we use custom fold. MS 2010/04 When converting UniqFM to use Data.IntMap, the fold cannot use UniqFM internal representation any more. But it is imperative that the assSqueeze stops the folding if the count gets greater or equal to maxCount. We thus convert UniqFM to a (lazy) list, do the fold and stops if necessary, which was the most efficient variant tried. Benchmark compiling 10-times SHA1.lhs follows. (original = previous implementation, folding = fold of the whole UFM, lazyFold = the current implementation, hackFold = using internal representation of Data.IntMap) original folding hackFold lazyFold -O -fasm (used everywhere) 31.509s 30.387s 30.791s 30.603s 100.00% 96.44% 97.72% 97.12% -fregs-graph 67.938s 74.875s 62.673s 64.679s 100.00% 110.21% 92.25% 95.20% -fregs-iterative 89.761s 143.913s 81.075s 86.912s 100.00% 160.33% 90.32% 96.83% -fnew-codegen 38.225s 37.142s 37.551s 37.119s 100.00% 97.17% 98.24% 97.11% -fnew-codegen -fregs-graph 91.786s 91.51s 87.368s 86.88s 100.00% 99.70% 95.19% 94.65% -fnew-codegen -fregs-iterative 206.72s 343.632s 194.694s 208.677s 100.00% 166.23% 94.18% 100.95% -} trivColorable :: Platform -> (RegClass -> VirtualReg -> FastInt) -> (RegClass -> RealReg -> FastInt) -> Triv VirtualReg RegClass RealReg trivColorable platform virtualRegSqueeze realRegSqueeze RcInteger conflicts exclusions | let !cALLOCATABLE_REGS_INTEGER = iUnbox (case platformArch platform of ArchX86 -> 3 ArchX86_64 -> 5 ArchPPC -> 16 ArchSPARC -> 14 ArchPPC_64 -> panic "trivColorable ArchPPC_64" ArchARM -> panic "trivColorable ArchARM" ArchUnknown -> panic "trivColorable ArchUnknown") , count2 <- accSqueeze (_ILIT(0)) cALLOCATABLE_REGS_INTEGER (virtualRegSqueeze RcInteger) conflicts , count3 <- accSqueeze count2 cALLOCATABLE_REGS_INTEGER (realRegSqueeze RcInteger) exclusions = count3 <# cALLOCATABLE_REGS_INTEGER trivColorable platform virtualRegSqueeze realRegSqueeze RcFloat conflicts exclusions | let !cALLOCATABLE_REGS_FLOAT = iUnbox (case platformArch platform of ArchX86 -> 0 ArchX86_64 -> 0 ArchPPC -> 0 ArchSPARC -> 22 ArchPPC_64 -> panic "trivColorable ArchPPC_64" ArchARM -> panic "trivColorable ArchARM" ArchUnknown -> panic "trivColorable ArchUnknown") , count2 <- accSqueeze (_ILIT(0)) cALLOCATABLE_REGS_FLOAT (virtualRegSqueeze RcFloat) conflicts , count3 <- accSqueeze count2 cALLOCATABLE_REGS_FLOAT (realRegSqueeze RcFloat) exclusions = count3 <# cALLOCATABLE_REGS_FLOAT trivColorable platform virtualRegSqueeze realRegSqueeze RcDouble conflicts exclusions | let !cALLOCATABLE_REGS_DOUBLE = iUnbox (case platformArch platform of ArchX86 -> 6 ArchX86_64 -> 0 ArchPPC -> 26 ArchSPARC -> 11 ArchPPC_64 -> panic "trivColorable ArchPPC_64" ArchARM -> panic "trivColorable ArchARM" ArchUnknown -> panic "trivColorable ArchUnknown") , count2 <- accSqueeze (_ILIT(0)) cALLOCATABLE_REGS_DOUBLE (virtualRegSqueeze RcDouble) conflicts , count3 <- accSqueeze count2 cALLOCATABLE_REGS_DOUBLE (realRegSqueeze RcDouble) exclusions = count3 <# cALLOCATABLE_REGS_DOUBLE trivColorable platform virtualRegSqueeze realRegSqueeze RcDoubleSSE conflicts exclusions | let !cALLOCATABLE_REGS_SSE = iUnbox (case platformArch platform of ArchX86 -> 8 ArchX86_64 -> 10 ArchPPC -> 0 ArchSPARC -> 0 ArchPPC_64 -> panic "trivColorable ArchPPC_64" ArchARM -> panic "trivColorable ArchARM" ArchUnknown -> panic "trivColorable ArchUnknown") , count2 <- accSqueeze (_ILIT(0)) cALLOCATABLE_REGS_SSE (virtualRegSqueeze RcDoubleSSE) conflicts , count3 <- accSqueeze count2 cALLOCATABLE_REGS_SSE (realRegSqueeze RcDoubleSSE) exclusions = count3 <# cALLOCATABLE_REGS_SSE -- Specification Code ---------------------------------------------------------- -- -- The trivColorable function for each particular architecture should -- implement the following function, but faster. -- {- trivColorable :: RegClass -> UniqSet Reg -> UniqSet Reg -> Bool trivColorable classN conflicts exclusions = let acc :: Reg -> (Int, Int) -> (Int, Int) acc r (cd, cf) = case regClass r of RcInteger -> (cd+1, cf) RcFloat -> (cd, cf+1) _ -> panic "Regs.trivColorable: reg class not handled" tmp = foldUniqSet acc (0, 0) conflicts (countInt, countFloat) = foldUniqSet acc tmp exclusions squeese = worst countInt classN RcInteger + worst countFloat classN RcFloat in squeese < allocatableRegsInClass classN -- | Worst case displacement -- node N of classN has n neighbors of class C. -- -- We currently only have RcInteger and RcDouble, which don't conflict at all. -- This is a bit boring compared to what's in RegArchX86. -- worst :: Int -> RegClass -> RegClass -> Int worst n classN classC = case classN of RcInteger -> case classC of RcInteger -> min n (allocatableRegsInClass RcInteger) RcFloat -> 0 RcDouble -> case classC of RcFloat -> min n (allocatableRegsInClass RcFloat) RcInteger -> 0 -- allocatableRegs is allMachRegNos with the fixed-use regs removed. -- i.e., these are the regs for which we are prepared to allow the -- register allocator to attempt to map VRegs to. allocatableRegs :: [RegNo] allocatableRegs = let isFree i = isFastTrue (freeReg i) in filter isFree allMachRegNos -- | The number of regs in each class. -- We go via top level CAFs to ensure that we're not recomputing -- the length of these lists each time the fn is called. allocatableRegsInClass :: RegClass -> Int allocatableRegsInClass cls = case cls of RcInteger -> allocatableRegsInteger RcFloat -> allocatableRegsDouble allocatableRegsInteger :: Int allocatableRegsInteger = length $ filter (\r -> regClass r == RcInteger) $ map RealReg allocatableRegs allocatableRegsFloat :: Int allocatableRegsFloat = length $ filter (\r -> regClass r == RcFloat $ map RealReg allocatableRegs -}