[project @ 2003-02-07 09:39:02 by simonpj]

Fix minor bugs in simplifier iteration control

diff --git a/ghc/compiler/main/DriverFlags.hs b/ghc/compiler/main/DriverFlags.hs
index 62e6524..14fa847 100644 (file)
--- a/ghc/compiler/main/DriverFlags.hs
+++ b/ghc/compiler/main/DriverFlags.hs
@@ -1,5 +1,5 @@
 -----------------------------------------------------------------------------
--- $Id: DriverFlags.hs,v 1.111 2003/02/04 15:09:40 simonpj Exp $
+-- $Id: DriverFlags.hs,v 1.112 2003/02/07 09:39:02 simonpj Exp $
 --
 -- Driver flags
 --
@@ -314,7 +314,7 @@ static_flags =
   ,  ( "fno-asm-mangling"  , NoArg (writeIORef v_Do_asm_mangling False) )
 
   ,  ( "fmax-simplifier-iterations", 
-               Prefix (writeIORef v_MaxSimplifierIterations . read) )
+               PrefixPred (all isDigit) (writeIORef v_MaxSimplifierIterations . read) )
 
   ,  ( "frule-check", 
                SepArg (\s -> writeIORef v_RuleCheck (Just s)) )

diff --git a/ghc/compiler/simplCore/SimplCore.lhs b/ghc/compiler/simplCore/SimplCore.lhs
index c7e484f..17b322b 100644 (file)
--- a/ghc/compiler/simplCore/SimplCore.lhs
+++ b/ghc/compiler/simplCore/SimplCore.lhs
@@ -457,6 +457,23 @@ simplifyPgm dflags rule_base
     max_iterations    = intSwitchSet sw_chkr MaxSimplifierIterations `orElse` 2
  
     iteration us iteration_no counts binds
+       -- iteration_no is the number of the iteration we are
+       -- about to begin, with '1' for the first
+      | iteration_no > max_iterations  -- Stop if we've run out of iterations
+      = do {
+#ifdef DEBUG
+           if  max_iterations > 2 then
+               hPutStr stderr ("NOTE: Simplifier still going after " ++ 
+                               show max_iterations ++ 
+                               " iterations; bailing out.\n")
+           else 
+               return ();
+#endif
+               -- Subtract 1 from iteration_no to get the
+               -- number of iterations we actually completed
+           return ("Simplifier baled out", iteration_no - 1, counts, binds)
+       }
+
       -- Try and force thunks off the binds; significantly reduces
       -- space usage, especially with -O.  JRS, 000620.
       | let sz = coreBindsSize binds in sz == sz
@@ -475,7 +492,7 @@ simplifyPgm dflags rule_base
                --      t = initSmpl ...
                --      counts' = snd t
                --   in
-               --      case t of {(_,counts') -> if counts'=0 then ...
+               --      case t of {(_,counts') -> if counts'=0 then ... }
                -- So the conditional didn't force counts', because the
                -- selection got duplicated.  Sigh!
           case initSmpl dflags us1 (simplTopBinds simpl_env tagged_binds) of {
@@ -498,27 +515,12 @@ simplifyPgm dflags rule_base
 
                -- Dump the result of this iteration
           dumpIfSet_dyn dflags Opt_D_dump_simpl_iterations herald
-                    (pprSimplCount counts') ;
+                        (pprSimplCount counts') ;
 
           endPass dflags herald Opt_D_dump_simpl_iterations binds' ;
 
-               -- Stop if we've run out of iterations
-          if iteration_no == max_iterations then
-               do {
-#ifdef DEBUG
-                   if  max_iterations > 2 then
-                           hPutStr stderr ("NOTE: Simplifier still going after " ++ 
-                                   show max_iterations ++ 
-                                   " iterations; bailing out.\n")
-                   else 
-#endif
-                       return ();
-
-                   return ("Simplifier baled out", iteration_no, all_counts, binds')
-               }
-
-               -- Else loop
-          else iteration us2 (iteration_no + 1) all_counts binds'
+               -- Loop
+          iteration us2 (iteration_no + 1) all_counts binds'
        }  } } }
       where
          (us1, us2) = splitUniqSupply us