X-Git-Url: http://git.megacz.com/?p=ghc-hetmet.git;a=blobdiff_plain;f=compiler%2Fcmm%2FOptimizationFuel.hs;h=175dcd09b18a4c602cb9531796d0f4b7abf89673;hp=a5d8fa3c0944271bb25ab65e856e4a5448b34044;hb=edc0bafd3fcd01b85a2e8894e5dfe149eb0e0857;hpb=6bc92166180824bf046d31e378359e3c386150f9

diff --git a/compiler/cmm/OptimizationFuel.hs b/compiler/cmm/OptimizationFuel.hs
index a5d8fa3..175dcd0 100644
--- a/compiler/cmm/OptimizationFuel.hs
+++ b/compiler/cmm/OptimizationFuel.hs
@@ -1,3 +1,9 @@
+-- | Optimisation fuel is used to control the amount of work the optimiser does.
+--
+-- Every optimisation step consumes a certain amount of fuel and stops when
+-- it runs out of fuel.  This can be used e.g. to debug optimiser bugs: Run
+-- the optimiser with varying amount of fuel to find out the exact number of
+-- steps where a bug is introduced in the output.
 module OptimizationFuel
     ( OptimizationFuel,  canRewriteWithFuel, maybeRewriteWithFuel, oneLessFuel
     , OptFuelState, initOptFuelState --, setTotalFuel
@@ -17,7 +23,7 @@ import ZipCfg
 --import GHC.Exts (State#)
 import Panic
 import Data.IORef
-import Monad
+import Control.Monad
 import StaticFlags (opt_Fuel)
 import UniqSupply
 
@@ -128,8 +134,7 @@ fuelDecrementState new_optimizer old new s =
         optimizer = if diffFuel old new > 0 then new_optimizer else fs_lastpass s
 
 -- lGraphOfGraph is here because we need uniques to implement it.
-lGraphOfGraph :: Graph m l -> Int -> FuelMonad (LGraph m l)
-lGraphOfGraph (Graph tail blocks) args =
+lGraphOfGraph :: Graph m l -> FuelMonad (LGraph m l)
+lGraphOfGraph (Graph tail blocks) =
   do entry <- liftM BlockId $ getUniqueM
-     return $ LGraph entry args
-                     (insertBlock (Block entry emptyStackInfo tail) blocks)
+     return $ LGraph entry (insertBlock (Block entry tail) blocks)