TysWiredIn is now warning-free

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

diff --git a/compiler/simplCore/FloatOut.lhs b/compiler/simplCore/FloatOut.lhs
index d554451..d0a27de 100644 (file)
--- a/compiler/simplCore/FloatOut.lhs
+++ b/compiler/simplCore/FloatOut.lhs
@@ -6,12 +6,17 @@
 ``Long-distance'' floating of bindings towards the top level.
 
 \begin{code}
-module FloatOut ( floatOutwards ) where
+{-# 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/Commentary/CodingStyle#Warnings
+-- for details
 
-#include "HsVersions.h"
+module FloatOut ( floatOutwards ) where
 
 import CoreSyn
-import CoreUtils       ( mkSCC, exprIsHNF, exprIsTrivial )
+import CoreUtils
 
 import DynFlags        ( DynFlags, DynFlag(..), FloatOutSwitches(..) )
 import ErrUtils                ( dumpIfSet_dyn )
@@ -24,6 +29,7 @@ import SetLevels      ( Level(..), LevelledExpr, LevelledBind,
 import UniqSupply       ( UniqSupply )
 import List            ( partition )
 import Outputable
+import FastString
 \end{code}
 
        -----------------
@@ -129,9 +135,9 @@ floatOutwards float_sws dflags us pgm
        let { (tlets, ntlets, lams) = get_stats (sum_stats fss) };
 
        dumpIfSet_dyn dflags Opt_D_dump_simpl_stats "FloatOut stats:"
-               (hcat [ int tlets,  ptext SLIT(" Lets floated to top level; "),
-                       int ntlets, ptext SLIT(" Lets floated elsewhere; from "),
-                       int lams,   ptext SLIT(" Lambda groups")]);
+               (hcat [ int tlets,  ptext (sLit " Lets floated to top level; "),
+                       int ntlets, ptext (sLit " Lets floated elsewhere; from "),
+                       int lams,   ptext (sLit " Lambda groups")]);
 
        endPass dflags float_msg  Opt_D_verbose_core2core (concat binds_s')
                        {- no specific flag for dumping float-out -} 
@@ -224,7 +230,7 @@ floatCaseAlt lvl arg        -- Used rec rhss, and case-alternative rhss
 floatRhs lvl arg       -- Used for nested non-rec rhss, and fn args
                        -- See Note [Floating out of RHS]
   = case (floatExpr lvl arg) of { (fsa, floats, arg') ->
-    if exprIsHNF arg' || exprIsTrivial arg' then
+    if exprIsCheap arg' then   
        (fsa, floats, arg')
     else
     case (partitionByMajorLevel lvl floats) of { (floats', heres) ->
@@ -250,6 +256,9 @@ floatRhs lvl arg    -- Used for nested non-rec rhss, and fn args
 --     bindings just after the '='.  And some of them might (correctly)
 --     be strict even though the 'let f' is lazy, because f, being a value,
 --     gets its demand-info zapped by the simplifier.
+--
+-- We use exprIsCheap because that is also what's used by the simplifier
+-- to decide whether to float a let out of a let
 
 floatExpr _ (Var v)   = (zeroStats, [], Var v)
 floatExpr _ (Type ty) = (zeroStats, [], Type ty)
@@ -305,13 +314,11 @@ floatExpr lvl (Note note@(SCC cc) expr)
          = Rec [(binder, mkSCC dupd_cc rhs) | (binder, rhs) <- pairs]
 
 floatExpr lvl (Note InlineMe expr)     -- Other than SCCs
-  = case floatExpr InlineCtxt expr of { (fs, floating_defns, expr') ->
-       -- There can be some floating_defns, arising from
-       -- ordinary lets that were there all the time.  It seems
-       -- more efficient to test once here than to avoid putting
-       -- them into floating_defns (which would mean testing for
-       -- inlineCtxt  at every let)
-    (fs, [], Note InlineMe (install floating_defns expr')) }   -- See notes in SetLevels
+  = (zeroStats, [], Note InlineMe (unTag expr))
+       -- Do no floating at all inside INLINE. [_$_]
+       -- The SetLevels pass did not clone the bindings, so it's
+       -- unsafe to do any floating, even if we dump the results
+       -- inside the Note (which is what we used to do).
 
 floatExpr lvl (Note note expr) -- Other than SCCs
   = case (floatExpr lvl expr)    of { (fs, floating_defns, expr') ->
@@ -353,6 +360,22 @@ floatList f [] = (zeroStats, [], [])
 floatList f (a:as) = case f a           of { (fs_a,  binds_a,  b)  ->
                     case floatList f as of { (fs_as, binds_as, bs) ->
                     (fs_a `add_stats` fs_as, binds_a ++ binds_as, b:bs) }}
+
+unTagBndr :: TaggedBndr tag -> CoreBndr
+unTagBndr (TB b _) = b
+
+unTag :: TaggedExpr tag -> CoreExpr
+unTag (Var v)            = Var v
+unTag (Lit l)            = Lit l
+unTag (Type ty)   = Type ty
+unTag (Note n e)  = Note n (unTag e)
+unTag (App e1 e2) = App (unTag e1) (unTag e2)
+unTag (Lam b e)   = Lam (unTagBndr b) (unTag e)
+unTag (Cast e co) = Cast (unTag e) co
+unTag (Let (Rec prs) e)    = Let (Rec [(unTagBndr b,unTag r) | (b, r) <- prs]) (unTag e)
+unTag (Let (NonRec b r) e) = Let (NonRec (unTagBndr b) (unTag r)) (unTag e)
+unTag (Case e b ty alts)   = Case (unTag e) (unTagBndr b) ty
+                                 [(c, map unTagBndr bs, unTag r) | (c,bs,r) <- alts]
 \end{code}
 
 %************************************************************************