Use OPTIONS rather than OPTIONS_GHC for pragmas

[ghc-hetmet.git] / compiler / nativeGen / RegAllocLinear.hs

diff --git a/compiler/nativeGen/RegAllocLinear.hs b/compiler/nativeGen/RegAllocLinear.hs
index d9ff121..4d6b556 100644 (file)
--- a/compiler/nativeGen/RegAllocLinear.hs
+++ b/compiler/nativeGen/RegAllocLinear.hs
@@ -1,3 +1,10 @@
+{-# 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
+
 -----------------------------------------------------------------------------
 --
 -- The register allocator
@@ -99,6 +106,7 @@ import UniqSet
 import UniqFM
 import UniqSupply
 import Outputable
+import State
 
 #ifndef DEBUG
 import Data.Maybe      ( fromJust )
@@ -498,7 +506,15 @@ genRaInsn block_live new_instrs instr r_dying w_dying =
     -- (j) free up stack slots for dead spilled regs
     -- TODO (can't be bothered right now)
 
-    return (patched_instr : w_spills ++ reverse r_spills
+    -- erase reg->reg moves where the source and destination are the same.
+    -- If the src temp didn't die in this instr but happened to be allocated
+    -- to the same real reg as the destination, then we can erase the move anyway.
+       squashed_instr  = case isRegRegMove patched_instr of
+                               Just (src, dst)
+                                | src == dst   -> []
+                               _               -> [patched_instr]
+
+    return (squashed_instr ++ w_spills ++ reverse r_spills
                 ++ clobber_saves ++ new_instrs,
            fixup_blocks)
   }}
@@ -1046,10 +1062,29 @@ binSpillReasons reasons
                        SpillJoinRM r   -> (r, [0, 0, 0, 0, 1])) reasons)
 
 
+-- | Count reg-reg moves remaining in this code.
+countRegRegMovesNat :: NatCmmTop -> Int
+countRegRegMovesNat cmm
+       = execState (mapGenBlockTopM countBlock cmm) 0
+ where
+       countBlock b@(BasicBlock i instrs)
+        = do   instrs' <- mapM countInstr instrs
+               return  b
+
+       countInstr instr
+               | Just _        <- isRegRegMove instr
+               = do    modify (+ 1)
+                       return instr
+
+               | otherwise
+               =       return instr
+
+
 -- | Pretty print some RegAllocStats
-pprStats :: [RegAllocStats] -> SDoc
-pprStats statss
- = let spills          = foldl' (plusUFM_C (zipWith (+)))
+pprStats :: [NatCmmTop] -> [RegAllocStats] -> SDoc
+pprStats code statss
+ = let -- sum up all the instrs inserted by the spiller
+       spills          = foldl' (plusUFM_C (zipWith (+)))
                                emptyUFM
                        $ map ra_spillInstrs statss
 
@@ -1057,12 +1092,15 @@ pprStats statss
                                [0, 0, 0, 0, 0]
                        $ eltsUFM spills
 
+       -- count how many reg-reg-moves remain in the code
+       moves           = sum $ map countRegRegMovesNat code
+
        pprSpill (reg, spills)
                = parens $ (hcat $ punctuate (text ", ")  (doubleQuotes (ppr reg) : map ppr spills))
 
    in  (  text "-- spills-added-total"
-       $$ text "--    (allocs, clobbers, loads, joinRR, joinRM)"
-       $$ (parens $ (hcat $ punctuate (text ", ") (map ppr spillTotals)))
+       $$ text "--    (allocs, clobbers, loads, joinRR, joinRM, reg_reg_moves_remaining)"
+       $$ (parens $ (hcat $ punctuate (text ", ") (map ppr spillTotals ++ [ppr moves])))
        $$ text ""
        $$ text "-- spills-added"
        $$ text "--    (reg_name, allocs, clobbers, loads, joinRR, joinRM)"