[project @ 2001-11-19 16:34:12 by simonpj]

[ghc-hetmet.git] / ghc / compiler / simplCore / FloatIn.lhs

diff --git a/ghc/compiler/simplCore/FloatIn.lhs b/ghc/compiler/simplCore/FloatIn.lhs
index 72d7649..2957520 100644 (file)
--- a/ghc/compiler/simplCore/FloatIn.lhs
+++ b/ghc/compiler/simplCore/FloatIn.lhs
@@ -22,10 +22,10 @@ import CoreUtils    ( exprIsValue, exprIsDupable )
 import CoreLint                ( showPass, endPass )
 import CoreFVs         ( CoreExprWithFVs, freeVars, freeVarsOf )
 import Id              ( isOneShotLambda )
-import Var             ( Id, idType, isTyVar )
+import Var             ( Id, idType )
 import Type            ( isUnLiftedType )
 import VarSet
-import Util            ( zipEqual, zipWithEqual )
+import Util            ( zipEqual, zipWithEqual, count )
 import Outputable
 \end{code}
 
@@ -182,13 +182,17 @@ So we treat lambda in groups, using the following rule:
 fiExpr to_drop (_, AnnLam b body)
   = case collect [b] body of
       (bndrs, real_body)
-       | all is_ok bndrs -> mkLams bndrs (fiExpr to_drop real_body)
+--     | all is_ok bndrs -> mkLams bndrs (fiExpr to_drop real_body)
+-- [July 01: I'm experiment with getting the full laziness
+-- pass to floats bindings out past big lambdas (instead of the simplifier)
+-- so I don't want the float-in pass to just push them right back in.
+-- I'm going to try just dumping all bindings outside lambdas.]
        | otherwise       -> mkCoLets' to_drop (mkLams bndrs (fiExpr [] real_body))
   where
     collect bs (_, AnnLam b body) = collect (b:bs) body
     collect bs body              = (reverse bs, body)
 
-    is_ok bndr = isTyVar bndr || isOneShotLambda bndr
+--    is_ok bndr = isTyVar bndr || isOneShotLambda bndr
 \end{code}
 
 We don't float lets inwards past an SCC.
@@ -420,7 +424,7 @@ sepBindsByDropPoint is_case drop_pts floaters
                --        E -> ...not mentioning x...
 
          n_alts      = length used_in_flags
-         n_used_alts = length [() | True <- used_in_flags]
+         n_used_alts = count id used_in_flags -- returns number of Trues in list.
 
          can_push = n_used_alts == 1           -- Used in just one branch
                   || (is_case &&               -- We are looking at case alternatives