Refactor MachRegs.trivColorable to do unboxed accumulation

[ghc-hetmet.git] / compiler / nativeGen / MachRegs.lhs

diff --git a/compiler/nativeGen/MachRegs.lhs b/compiler/nativeGen/MachRegs.lhs
index dd4962c..ee514f9 100644 (file)
--- a/compiler/nativeGen/MachRegs.lhs
+++ b/compiler/nativeGen/MachRegs.lhs
@@ -103,6 +103,9 @@ import Unique
 import UniqSet
 import Constants
 import FastTypes
+import UniqFM
+
+import GHC.Exts
 
 #if powerpc_TARGET_ARCH
 import Data.Word       ( Word8, Word16, Word32 )
@@ -444,24 +447,30 @@ instance Outputable Reg where
 --     NOTE:   This only works for arcitectures with just RcInteger and RcDouble
 --             (which are disjoint) ie. x86, x86_64 and ppc
 --
+
+--     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.
+{-
 trivColorable :: RegClass -> UniqSet Reg -> UniqSet Reg -> Bool
 trivColorable classN conflicts exclusions
- = let 
+ = let
+
+       acc :: Reg -> (Int, Int) -> (Int, Int)
        acc r (cd, cf)  
         = case regClass r of
                RcInteger       -> (cd+1, cf)
                RcDouble        -> (cd,   cf+1)
                _               -> panic "MachRegs.trivColorable: reg class not handled"
 
-       tmp             = foldUniqSet acc (0, 0) conflicts
-       (rsD,  rsFP)    = foldUniqSet acc tmp    exclusions
+       tmp                     = foldUniqSet acc (0, 0) conflicts
+       (countInt,  countFloat) = foldUniqSet acc tmp    exclusions
 
-       squeese         = worst rsD  classN RcInteger
-                       + worst rsFP classN RcDouble
+       squeese         = worst countInt   classN RcInteger
+                       + worst countFloat classN RcDouble
 
    in  squeese < allocatableRegsInClass classN
 
-
 -- | Worst case displacement
 --     node N of classN has n neighbors of class C.
 --
@@ -480,6 +489,69 @@ worst n classN classC
         -> case classC of
                RcDouble        -> min n (allocatableRegsInClass RcDouble)
                RcInteger       -> 0
+-}
+
+
+-- The number of allocatable regs is hard coded 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.
+--
+-- There is an allocatableRegsInClass :: RegClass -> Int, but doing the unboxing
+-- is too slow for us here.
+--
+-- Compare MachRegs.freeRegs  and MachRegs.h to get these numbers.
+--
+#if i386_TARGET_ARCH
+#define ALLOCATABLE_REGS_INTEGER 3#
+#define ALLOCATABLE_REGS_DOUBLE  6#
+#endif
+
+#if x86_64_TARGET_ARCH
+#define ALLOCATABLE_REGS_INTEGER 5#
+#define ALLOCATABLE_REGS_DOUBLE  2#
+#endif
+
+#if powerpc_TARGET_ARCH
+#define ALLOCATABLE_REGS_INTEGER 16#
+#define ALLOCATABLE_REGS_DOUBLE  26#
+#endif
+
+{-# INLINE regClass      #-}
+trivColorable :: RegClass -> UniqSet Reg -> UniqSet Reg -> Bool
+trivColorable classN conflicts exclusions
+ = {-# SCC "trivColorable" #-}
+   let
+       {-# INLINE   isSqueesed    #-}
+       isSqueesed cI cF ufm
+         = case ufm of
+               NodeUFM _ _ left right
+                -> case isSqueesed cI cF right of
+                       (# s, cI', cF' #)
+                        -> case s of
+                               False   -> isSqueesed cI' cF' left
+                               True    -> (# True, cI', cF' #)
+
+               LeafUFM _ reg
+                -> case regClass reg of
+                       RcInteger
+                        -> case cI +# 1# of
+                               cI' -> (# cI' >=# ALLOCATABLE_REGS_INTEGER, cI', cF #)
+
+                       RcDouble
+                        -> case cF +# 1# of
+                               cF' -> (# cF' >=# ALLOCATABLE_REGS_DOUBLE,  cI, cF' #)
+
+               EmptyUFM
+                ->     (# False, cI, cF #)
+
+   in case isSqueesed 0# 0# conflicts of
+       (# False, cI', cF' #)
+        -> case isSqueesed cI' cF' exclusions of
+               (# s, _, _ #)   -> not s
+
+       (# True, _, _ #)
+        -> False
+
 
 
 -- -----------------------------------------------------------------------------