Merge branch 'master' of http://darcs.haskell.org/ghc

17 files changed, 312 insertions, 223 deletions

diff --git a/compiler/coreSyn/CoreFVs.lhs b/compiler/coreSyn/CoreFVs.lhs
index c130921dbf..33017227b4 100644
--- a/compiler/coreSyn/CoreFVs.lhs
+++ b/compiler/coreSyn/CoreFVs.lhs
@@ -332,8 +332,9 @@ Also since rule_fn is a Name, not a Var, we have to use the grungy delUFM.
 vectsFreeVars :: [CoreVect] -> VarSet
 vectsFreeVars = foldr (unionVarSet . vectFreeVars) emptyVarSet
   where
-    vectFreeVars (Vect _ Nothing)    = noFVs
-    vectFreeVars (Vect _ (Just rhs)) = expr_fvs rhs isLocalId emptyVarSet
+    vectFreeVars (Vect   _ Nothing)    = noFVs
+    vectFreeVars (Vect   _ (Just rhs)) = expr_fvs rhs isLocalId emptyVarSet
+    vectFreeVars (NoVect _)            = noFVs
 \end{code}
 
 
diff --git a/compiler/coreSyn/CoreSubst.lhs b/compiler/coreSyn/CoreSubst.lhs
index acf17e3c12..0c954a8927 100644
--- a/compiler/coreSyn/CoreSubst.lhs
+++ b/compiler/coreSyn/CoreSubst.lhs
@@ -714,8 +714,9 @@ substVects subst = map (substVect subst)
 
 ------------------
 substVect :: Subst -> CoreVect -> CoreVect
-substVect _subst (Vect v Nothing)    = Vect v Nothing
-substVect subst  (Vect v (Just rhs)) = Vect v (Just (simpleOptExprWith subst rhs))
+substVect _subst (Vect   v Nothing)    = Vect   v Nothing
+substVect subst  (Vect   v (Just rhs)) = Vect   v (Just (simpleOptExprWith subst rhs))
+substVect _subst (NoVect v)            = NoVect v
 
 ------------------
 substVarSet :: Subst -> VarSet -> VarSet
diff --git a/compiler/coreSyn/CoreSyn.lhs b/compiler/coreSyn/CoreSyn.lhs
index e754c6dda5..178d5cace7 100644
--- a/compiler/coreSyn/CoreSyn.lhs
+++ b/compiler/coreSyn/CoreSyn.lhs
@@ -417,14 +417,16 @@ Representation of desugared vectorisation declarations that are fed to the vecto
 'ModGuts').
 
 \begin{code}
-data CoreVect = Vect Id (Maybe CoreExpr)
+data CoreVect = Vect   Id (Maybe CoreExpr)
+              | NoVect Id
+
 \end{code}
 
 
 %************************************************************************
-%*									*
-		Unfoldings
-%*									*
+%*                                                                      *
+                Unfoldings
+%*                                                                      *
 %************************************************************************
 
 The @Unfolding@ type is declared here to avoid numerous loops
diff --git a/compiler/coreSyn/PprCore.lhs b/compiler/coreSyn/PprCore.lhs
index e9452dcb73..463f3c95fc 100644
--- a/compiler/coreSyn/PprCore.lhs
+++ b/compiler/coreSyn/PprCore.lhs
@@ -446,7 +446,7 @@ instance Outputable e => Outputable (DFunArg e) where
 \end{code}
 
 -----------------------------------------------------
---	Rules
+--      Rules
 -----------------------------------------------------
 
 \begin{code}
@@ -461,11 +461,23 @@ pprRule (BuiltinRule { ru_fn = fn, ru_name = name})
   = ptext (sLit "Built in rule for") <+> ppr fn <> colon <+> doubleQuotes (ftext name)
 
 pprRule (Rule { ru_name = name, ru_act = act, ru_fn = fn,
-		ru_bndrs = tpl_vars, ru_args = tpl_args,
-		ru_rhs = rhs })
+                ru_bndrs = tpl_vars, ru_args = tpl_args,
+                ru_rhs = rhs })
   = hang (doubleQuotes (ftext name) <+> ppr act)
        4 (sep [ptext (sLit "forall") <+> braces (sep (map pprTypedBinder tpl_vars)),
-	       nest 2 (ppr fn <+> sep (map pprArg tpl_args)),
-	       nest 2 (ptext (sLit "=") <+> pprCoreExpr rhs)
-	    ])
+               nest 2 (ppr fn <+> sep (map pprArg tpl_args)),
+               nest 2 (ptext (sLit "=") <+> pprCoreExpr rhs)
+            ])
+\end{code}
+
+-----------------------------------------------------
+--      Vectorisation declarations
+-----------------------------------------------------
+
+\begin{code}
+instance Outputable CoreVect where
+  ppr (Vect   var Nothing)  = ptext (sLit "VECTORISE SCALAR") <+> ppr var
+  ppr (Vect   var (Just e)) = hang (ptext (sLit "VECTORISE") <+> ppr var <+> char '=')
+                                4 (pprCoreExpr e)
+  ppr (NoVect var)          = ptext (sLit "NOVECTORISE") <+> ppr var
 \end{code}
diff --git a/compiler/deSugar/Desugar.lhs b/compiler/deSugar/Desugar.lhs
index 70679fbf4f..af2db3697b 100644
--- a/compiler/deSugar/Desugar.lhs
+++ b/compiler/deSugar/Desugar.lhs
@@ -394,16 +394,11 @@ the rule is precisly to optimise them:
 
 \begin{code}
 dsVect :: LVectDecl Id -> DsM CoreVect
-dsVect (L loc (HsVect v rhs))
+dsVect (L loc (HsVect (L _ v) rhs))
   = putSrcSpanDs loc $ 
     do { rhs' <- fmapMaybeM dsLExpr rhs
-       ; return $ Vect (unLoc v) rhs'
+       ; return $ Vect v rhs'
   	   }
--- dsVect (L loc (HsVect v Nothing))
---   = return $ Vect v Nothing
--- dsVect (L loc (HsVect v (Just rhs)))
---   = putSrcSpanDs loc $ 
---     do { rhs' <- dsLExpr rhs
---        ; return $ Vect v (Just rhs')
---       }
+dsVect (L _loc (HsNoVect (L _ v)))
+  = return $ NoVect v
 \end{code}
diff --git a/compiler/hsSyn/HsDecls.lhs b/compiler/hsSyn/HsDecls.lhs
index c05f26a5fc..3712cbd9f7 100644
--- a/compiler/hsSyn/HsDecls.lhs
+++ b/compiler/hsSyn/HsDecls.lhs
@@ -28,6 +28,7 @@ module HsDecls (
   collectRuleBndrSigTys,
   -- ** @VECTORISE@ declarations
   VectDecl(..), LVectDecl,
+  lvectDeclName,
   -- ** @default@ declarations
   DefaultDecl(..), LDefaultDecl,
   -- ** Top-level template haskell splice
@@ -1005,10 +1006,11 @@ instance OutputableBndr name => Outputable (RuleBndr name) where
 %*                                                                      *
 %************************************************************************
 
-A vectorisation pragma
+A vectorisation pragma, one of
 
-  {-# VECTORISE f = closure1 g (scalar_map g) #-} OR
+  {-# VECTORISE f = closure1 g (scalar_map g) #-}
   {-# VECTORISE SCALAR f #-}
+  {-# NOVECTORISE f #-}
   
 Note [Typechecked vectorisation pragmas]
 ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
@@ -1029,14 +1031,23 @@ data VectDecl name
   = HsVect
       (Located name)
       (Maybe (LHsExpr name))    -- 'Nothing' => SCALAR declaration
+  | HsNoVect
+      (Located name)
   deriving (Data, Typeable)
-      
+
+lvectDeclName :: LVectDecl name -> name
+lvectDeclName (L _ (HsVect   (L _ name) _)) = name
+lvectDeclName (L _ (HsNoVect (L _ name)))   = name
+
 instance OutputableBndr name => Outputable (VectDecl name) where
-  ppr (HsVect v rhs)
+  ppr (HsVect v Nothing)
+    = sep [text "{-# VECTORISE SCALAR" <+> ppr v <+> text "#-}" ]
+  ppr (HsVect v (Just rhs))
     = sep [text "{-# VECTORISE" <+> ppr v,
-           nest 4 (case rhs of
-                     Nothing  -> text "SCALAR #-}"
-                     Just rhs -> pprExpr (unLoc rhs) <+> text "#-}") ]
+           nest 4 $ 
+             pprExpr (unLoc rhs) <+> text "#-}" ]
+  ppr (HsNoVect v)
+    = sep [text "{-# NOVECTORISE" <+> ppr v <+> text "#-}" ]
 \end{code}
 
 %************************************************************************
diff --git a/compiler/parser/Lexer.x b/compiler/parser/Lexer.x
index 76a02d6c60..43a400471e 100644
--- a/compiler/parser/Lexer.x
+++ b/compiler/parser/Lexer.x
@@ -483,6 +483,7 @@ data Token
   | ITlanguage_prag
   | ITvect_prag
   | ITvect_scalar_prag
+  | ITnovect_prag
 
   | ITdotdot  			-- reserved symbols
   | ITcolon
@@ -2281,7 +2282,8 @@ oneWordPrags = Map.fromList([("rules", rulePrag),
                            ("core", token ITcore_prag),
                            ("unpack", token ITunpack_prag),
                            ("ann", token ITann_prag),
-                           ("vectorize", token ITvect_prag)])
+                           ("vectorize", token ITvect_prag),
+                           ("novectorize", token ITnovect_prag)])
 
 twoWordPrags = Map.fromList([("inline conlike", token (ITinline_prag Inline ConLike)),
                              ("notinline conlike", token (ITinline_prag NoInline ConLike)),
@@ -2307,6 +2309,7 @@ clean_pragma prag = canon_ws (map toLower (unprefix prag))
                                               "noinline" -> "notinline"
                                               "specialise" -> "specialize"
                                               "vectorise" -> "vectorize"
+                                              "novectorise" -> "novectorize"
                                               "constructorlike" -> "conlike"
                                               _ -> prag'
                           canon_ws s = unwords (map canonical (words s))
diff --git a/compiler/parser/Parser.y.pp b/compiler/parser/Parser.y.pp
index 01d768a4d7..b663ac2aba 100644
--- a/compiler/parser/Parser.y.pp
+++ b/compiler/parser/Parser.y.pp
@@ -252,21 +252,22 @@ incorrect.
  'by'       { L _ ITby }        -- for list transform extension
  'using'    { L _ ITusing }     -- for list transform extension
 
- '{-# INLINE'      	  { L _ (ITinline_prag _ _) }
- '{-# SPECIALISE'  	  { L _ ITspec_prag }
+ '{-# INLINE'             { L _ (ITinline_prag _ _) }
+ '{-# SPECIALISE'         { L _ ITspec_prag }
  '{-# SPECIALISE_INLINE'  { L _ (ITspec_inline_prag _) }
- '{-# SOURCE'	   { L _ ITsource_prag }
- '{-# RULES'	   { L _ ITrules_prag }
- '{-# CORE'        { L _ ITcore_prag }              -- hdaume: annotated core
- '{-# SCC'	   { L _ ITscc_prag }
- '{-# GENERATED'   { L _ ITgenerated_prag }
- '{-# DEPRECATED'  { L _ ITdeprecated_prag }
- '{-# WARNING'     { L _ ITwarning_prag }
- '{-# UNPACK'      { L _ ITunpack_prag }
- '{-# ANN'         { L _ ITann_prag }
+ '{-# SOURCE'      				{ L _ ITsource_prag }
+ '{-# RULES'       				{ L _ ITrules_prag }
+ '{-# CORE'        				{ L _ ITcore_prag }              -- hdaume: annotated core
+ '{-# SCC'                { L _ ITscc_prag }
+ '{-# GENERATED'          { L _ ITgenerated_prag }
+ '{-# DEPRECATED'         { L _ ITdeprecated_prag }
+ '{-# WARNING'            { L _ ITwarning_prag }
+ '{-# UNPACK'             { L _ ITunpack_prag }
+ '{-# ANN'                { L _ ITann_prag }
  '{-# VECTORISE'          { L _ ITvect_prag }
  '{-# VECTORISE_SCALAR'   { L _ ITvect_scalar_prag }
- '#-}'		   { L _ ITclose_prag }
+ '{-# NOVECTORISE'        { L _ ITnovect_prag }
+ '#-}'             				{ L _ ITclose_prag }
 
  '..'		{ L _ ITdotdot }  			-- reserved symbols
  ':'		{ L _ ITcolon }
@@ -546,33 +547,34 @@ ops   	:: { Located [Located RdrName] }
 -- Top-Level Declarations
 
 topdecls :: { OrdList (LHsDecl RdrName) }
-        : topdecls ';' topdecl		        { $1 `appOL` $3 }
-        | topdecls ';'			        { $1 }
-	| topdecl			        { $1 }
+        : topdecls ';' topdecl                  { $1 `appOL` $3 }
+        | topdecls ';'                          { $1 }
+        | topdecl                               { $1 }
 
 topdecl :: { OrdList (LHsDecl RdrName) }
-  	: cl_decl			{ unitOL (L1 (TyClD (unLoc $1))) }
-  	| ty_decl			{ unitOL (L1 (TyClD (unLoc $1))) }
-	| 'instance' inst_type where_inst
-	    { let (binds, sigs, ats, _) = cvBindsAndSigs (unLoc $3)
-	      in 
-	      unitOL (L (comb3 $1 $2 $3) (InstD (InstDecl $2 binds sigs ats)))}
+        : cl_decl                       { unitOL (L1 (TyClD (unLoc $1))) }
+        | ty_decl                       { unitOL (L1 (TyClD (unLoc $1))) }
+        | 'instance' inst_type where_inst
+            { let (binds, sigs, ats, _) = cvBindsAndSigs (unLoc $3)
+              in 
+              unitOL (L (comb3 $1 $2 $3) (InstD (InstDecl $2 binds sigs ats)))}
         | stand_alone_deriving                  { unitOL (LL (DerivD (unLoc $1))) }
-	| 'default' '(' comma_types0 ')'	{ unitOL (LL $ DefD (DefaultDecl $3)) }
-	| 'foreign' fdecl			{ unitOL (LL (unLoc $2)) }
+        | 'default' '(' comma_types0 ')'        { unitOL (LL $ DefD (DefaultDecl $3)) }
+        | 'foreign' fdecl                       { unitOL (LL (unLoc $2)) }
         | '{-# DEPRECATED' deprecations '#-}'   { $2 }
         | '{-# WARNING' warnings '#-}'          { $2 }
-	| '{-# RULES' rules '#-}'		{ $2 }
-	| '{-# VECTORISE_SCALAR' qvar '#-}'	{ unitOL $ LL $ VectD (HsVect $2 Nothing) }
-	| '{-# VECTORISE' qvar '=' exp '#-}'	{ unitOL $ LL $ VectD (HsVect $2 (Just $4)) }
-	| annotation { unitOL $1 }
-      	| decl					{ unLoc $1 }
-
-	-- Template Haskell Extension
-	-- The $(..) form is one possible form of infixexp
-	-- but we treat an arbitrary expression just as if 
-	-- it had a $(..) wrapped around it
-	| infixexp 				{ unitOL (LL $ mkTopSpliceDecl $1) } 
+        | '{-# RULES' rules '#-}'               { $2 }
+        | '{-# VECTORISE_SCALAR' qvar '#-}'     { unitOL $ LL $ VectD (HsVect   $2 Nothing) }
+        | '{-# VECTORISE' qvar '=' exp '#-}'    { unitOL $ LL $ VectD (HsVect   $2 (Just $4)) }
+        | '{-# NOVECTORISE' qvar '#-}'     			{ unitOL $ LL $ VectD (HsNoVect $2) }
+        | annotation { unitOL $1 }
+        | decl                                  { unLoc $1 }
+
+        -- Template Haskell Extension
+        -- The $(..) form is one possible form of infixexp
+        -- but we treat an arbitrary expression just as if 
+        -- it had a $(..) wrapped around it
+        | infixexp                              { unitOL (LL $ mkTopSpliceDecl $1) } 
 
 -- Type classes
 --
diff --git a/compiler/rename/RnSource.lhs b/compiler/rename/RnSource.lhs
index 54dc378dd5..6b8e5c09ba 100644
--- a/compiler/rename/RnSource.lhs
+++ b/compiler/rename/RnSource.lhs
@@ -666,6 +666,10 @@ rnHsVectDecl (HsVect var (Just rhs))
        ; (rhs', fv_rhs) <- rnLExpr rhs
        ; return (HsVect var' (Just rhs'), fv_rhs `addOneFV` unLoc var')
        }
+rnHsVectDecl (HsNoVect var)
+  = do { var' <- wrapLocM lookupTopBndrRn var
+       ; return (HsNoVect var', unitFV (unLoc var'))
+       }
 \end{code}
 
 %*********************************************************
diff --git a/compiler/simplCore/SimplCore.lhs b/compiler/simplCore/SimplCore.lhs
index 23a2472b23..59aba4b030 100644
--- a/compiler/simplCore/SimplCore.lhs
+++ b/compiler/simplCore/SimplCore.lhs
@@ -29,7 +29,7 @@ import FloatIn		( floatInwards )
 import FloatOut		( floatOutwards )
 import FamInstEnv
 import Id
-import BasicTypes       ( CompilerPhase, isDefaultInlinePragma )
+import BasicTypes
 import VarSet
 import VarEnv
 import LiberateCase	( liberateCase )
@@ -356,11 +356,18 @@ simplifyPgmIO pass@(CoreDoSimplify max_iterations mode)
       -- space usage, especially with -O.  JRS, 000620.
       | let sz = coreBindsSize binds in sz == sz
       = do {
-		-- Occurrence analysis
-	   let { tagged_binds = {-# SCC "OccAnal" #-} 
-                     occurAnalysePgm active_rule rules [] binds } ;
-	   Err.dumpIfSet_dyn dflags Opt_D_dump_occur_anal "Occurrence analysis"
-		     (pprCoreBindings tagged_binds);
+                -- Occurrence analysis
+           let {   -- During the 'InitialPhase' (i.e., before vectorisation), we need to make sure
+                   -- that the right-hand sides of vectorisation declarations are taken into 
+                   -- account during occurence analysis.
+                 maybeVects   = case sm_phase mode of
+                                  InitialPhase -> mg_vect_decls guts
+                                  _            -> []
+               ; tagged_binds = {-# SCC "OccAnal" #-} 
+                     occurAnalysePgm active_rule rules maybeVects binds 
+               } ;
+           Err.dumpIfSet_dyn dflags Opt_D_dump_occur_anal "Occurrence analysis"
+                     (pprCoreBindings tagged_binds);
 
 	   	-- Get any new rules, and extend the rule base
 		-- See Note [Overall plumbing for rules] in Rules.lhs
diff --git a/compiler/typecheck/TcBinds.lhs b/compiler/typecheck/TcBinds.lhs
index 537da938d6..b5bbeb1940 100644
--- a/compiler/typecheck/TcBinds.lhs
+++ b/compiler/typecheck/TcBinds.lhs
@@ -598,7 +598,7 @@ impSpecErr name
 tcVectDecls :: [LVectDecl Name] -> TcM ([LVectDecl TcId])
 tcVectDecls decls 
   = do { decls' <- mapM (wrapLocM tcVect) decls
-       ; let ids  = [unLoc id | L _ (HsVect id _) <- decls']
+       ; let ids  = map lvectDeclName decls'
              dups = findDupsEq (==) ids
        ; mapM_ reportVectDups dups
        ; traceTcConstraints "End of tcVectDecls"
@@ -649,6 +649,11 @@ tcVect (HsVect name@(L loc _) (Just rhs))
         -- to the vectoriser - see "Note [Typechecked vectorisation pragmas]" in HsDecls
        ; return $ HsVect (L loc id') (Just rhsWrapped)
        }
+tcVect (HsNoVect name)
+  = addErrCtxt (vectCtxt name) $
+    do { id <- wrapLocM tcLookupId name
+       ; return $ HsNoVect id
+       }
 
 vectCtxt :: Located Name -> SDoc
 vectCtxt name = ptext (sLit "When checking the vectorisation declaration for") <+> ppr name
diff --git a/compiler/typecheck/TcHsSyn.lhs b/compiler/typecheck/TcHsSyn.lhs
index 12b50acff0..3b4afaea48 100644
--- a/compiler/typecheck/TcHsSyn.lhs
+++ b/compiler/typecheck/TcHsSyn.lhs
@@ -1027,6 +1027,10 @@ zonkVect env (HsVect v (Just e))
        ; e' <- zonkLExpr env e
        ; return $ HsVect v' (Just e')
        }
+zonkVect env (HsNoVect v)
+  = do { v' <- wrapLocM (zonkIdBndr env) v
+       ; return $ HsNoVect v'
+       }
 \end{code}
 
 %************************************************************************
diff --git a/compiler/vectorise/Vectorise.hs b/compiler/vectorise/Vectorise.hs
index 4994e3f165..35ddd9d9a8 100644
--- a/compiler/vectorise/Vectorise.hs
+++ b/compiler/vectorise/Vectorise.hs
@@ -1,4 +1,3 @@
-{-# OPTIONS -fno-warn-missing-signatures -fno-warn-unused-do-bind #-}
 
 module Vectorise ( vectorise )
 where
@@ -82,98 +81,124 @@ vectModule guts@(ModGuts { mg_types     = types
                       }
       }
 
--- | Try to vectorise a top-level binding.
---   If it doesn't vectorise then return it unharmed.
+-- |Try to vectorise a top-level binding.  If it doesn't vectorise then return it unharmed.
 --
---   For example, for the binding 
+-- For example, for the binding 
 --
---   @  
---      foo :: Int -> Int
---      foo = \x -> x + x
---   @
---  
---   we get
---   @
---      foo  :: Int -> Int
---      foo  = \x -> vfoo $: x                  
--- 
---      v_foo :: Closure void vfoo lfoo
---      v_foo = closure vfoo lfoo void        
--- 
---      vfoo :: Void -> Int -> Int
---      vfoo = ...
+-- @  
+--    foo :: Int -> Int
+--    foo = \x -> x + x
+-- @
 --
---      lfoo :: PData Void -> PData Int -> PData Int
---      lfoo = ...
---   @ 
+-- we get
+-- @
+--    foo  :: Int -> Int
+--    foo  = \x -> vfoo $: x                  
 --
---   @vfoo@ is the "vectorised", or scalar, version that does the same as the original
---   function foo, but takes an explicit environment.
--- 
---   @lfoo@ is the "lifted" version that works on arrays.
+--    v_foo :: Closure void vfoo lfoo
+--    v_foo = closure vfoo lfoo void        
+--
+--    vfoo :: Void -> Int -> Int
+--    vfoo = ...
+--
+--    lfoo :: PData Void -> PData Int -> PData Int
+--    lfoo = ...
+-- @ 
 --
---   @v_foo@ combines both of these into a `Closure` that also contains the
---   environment.
+-- @vfoo@ is the "vectorised", or scalar, version that does the same as the original
+-- function foo, but takes an explicit environment.
 --
---   The original binding @foo@ is rewritten to call the vectorised version
---   present in the closure.
+-- @lfoo@ is the "lifted" version that works on arrays.
+--
+-- @v_foo@ combines both of these into a `Closure` that also contains the
+-- environment.
+--
+-- The original binding @foo@ is rewritten to call the vectorised version
+-- present in the closure.
+--
+-- Vectorisation may be surpressed by annotating a binding with a 'NOVECTORISE' pragma.  If this
+-- pragma is used in a group of mutually recursive bindings, either all or no binding must have
+-- the pragma.  If only some bindings are annotated, a fatal error is being raised.
+-- FIXME: Once we support partial vectorisation, we may be able to vectorise parts of a group, or
+--   we may emit a warning and refrain from vectorising the entire group.
 --
 vectTopBind :: CoreBind -> VM CoreBind
 vectTopBind b@(NonRec var expr)
- = do {   -- Vectorise the right-hand side, create an appropriate top-level binding and add it to
-          -- the vectorisation map.
-      ; (inline, isScalar, expr') <- vectTopRhs [] var expr
-      ; var' <- vectTopBinder var inline expr'
-      ; when isScalar $ 
-          addGlobalScalar var
-
-          -- We replace the original top-level binding by a value projected from the vectorised
-          -- closure and add any newly created hoisted top-level bindings.
-      ; cexpr <- tryConvert var var' expr
-      ; hs <- takeHoisted
-      ; return . Rec $ (var, cexpr) : (var', expr') : hs
-      }
-  `orElseV`
-    return b
+  = unlessNoVectDecl $
+      do {   -- Vectorise the right-hand side, create an appropriate top-level binding and add it
+             -- to the vectorisation map.
+         ; (inline, isScalar, expr') <- vectTopRhs [] var expr
+         ; var' <- vectTopBinder var inline expr'
+         ; when isScalar $ 
+             addGlobalScalar var
+ 
+             -- We replace the original top-level binding by a value projected from the vectorised
+             -- closure and add any newly created hoisted top-level bindings.
+         ; cexpr <- tryConvert var var' expr
+         ; hs <- takeHoisted
+         ; return . Rec $ (var, cexpr) : (var', expr') : hs
+         }
+     `orElseV`
+       return b
+  where
+    unlessNoVectDecl vectorise
+      = do { hasNoVectDecl <- noVectDecl var
+           ; when hasNoVectDecl $
+               traceVt "NOVECTORISE" $ ppr var
+           ; if hasNoVectDecl then return b else vectorise
+           }
 vectTopBind b@(Rec bs)
- = let (vars, exprs) = unzip bs
-   in
-   do { (vars', _, exprs', hs) <- fixV $ 
-          \ ~(_, inlines, rhss, _) ->
-            do {   -- Vectorise the right-hand sides, create an appropriate top-level bindings and
-                   --  add them to the vectorisation map.
-               ; vars' <- sequence [vectTopBinder var inline rhs
-                                   | (var, ~(inline, rhs)) <- zipLazy vars (zip inlines rhss)]
-               ; (inlines, areScalars, exprs') <- mapAndUnzip3M (uncurry $ vectTopRhs vars) bs
-               ; hs <- takeHoisted
-               ; if and areScalars
-                 then      -- (1) Entire recursive group is scalar
-                           --      => add all variables to the global set of scalars
-                      do { mapM addGlobalScalar vars
-                         ; return (vars', inlines, exprs', hs)
-                         }
-                 else      -- (2) At least one binding is not scalar
-                           --     => vectorise again with empty set of local scalars
-                      do { (inlines, _, exprs') <- mapAndUnzip3M (uncurry $ vectTopRhs []) bs
-                         ; hs <- takeHoisted
-                         ; return (vars', inlines, exprs', hs)
-                         }
-               }
-                      
-          -- Replace the original top-level bindings by a values projected from the vectorised
-          -- closures and add any newly created hoisted top-level bindings to the group.
-      ; cexprs <- sequence $ zipWith3 tryConvert vars vars' exprs
-      ; return . Rec $ zip vars cexprs ++ zip vars' exprs' ++ hs
-      }
-  `orElseV`
-    return b    
-    
+  = unlessSomeNoVectDecl $
+      do { (vars', _, exprs', hs) <- fixV $ 
+             \ ~(_, inlines, rhss, _) ->
+               do {   -- Vectorise the right-hand sides, create an appropriate top-level bindings
+                      -- and add them to the vectorisation map.
+                  ; vars' <- sequence [vectTopBinder var inline rhs
+                                      | (var, ~(inline, rhs)) <- zipLazy vars (zip inlines rhss)]
+                  ; (inlines, areScalars, exprs') <- mapAndUnzip3M (uncurry $ vectTopRhs vars) bs
+                  ; hs <- takeHoisted
+                  ; if and areScalars
+                    then      -- (1) Entire recursive group is scalar
+                              --      => add all variables to the global set of scalars
+                         do { mapM_ addGlobalScalar vars
+                            ; return (vars', inlines, exprs', hs)
+                            }
+                    else      -- (2) At least one binding is not scalar
+                              --     => vectorise again with empty set of local scalars
+                         do { (inlines, _, exprs') <- mapAndUnzip3M (uncurry $ vectTopRhs []) bs
+                            ; hs <- takeHoisted
+                            ; return (vars', inlines, exprs', hs)
+                            }
+                  }
+                       
+             -- Replace the original top-level bindings by a values projected from the vectorised
+             -- closures and add any newly created hoisted top-level bindings to the group.
+         ; cexprs <- sequence $ zipWith3 tryConvert vars vars' exprs
+         ; return . Rec $ zip vars cexprs ++ zip vars' exprs' ++ hs
+         }
+     `orElseV`
+       return b    
+  where
+    (vars, exprs) = unzip bs
+
+    unlessSomeNoVectDecl vectorise
+      = do { hasNoVectDecls <- mapM noVectDecl vars
+           ; when (and hasNoVectDecls) $
+               traceVt "NOVECTORISE" $ ppr vars
+           ; if and hasNoVectDecls 
+             then return b                              -- all bindings have 'NOVECTORISE'
+             else if or hasNoVectDecls 
+             then cantVectorise noVectoriseErr (ppr b)  -- some (but not all) have 'NOVECTORISE'
+             else vectorise                             -- no binding has a 'NOVECTORISE' decl
+           }
+    noVectoriseErr = "NOVECTORISE must be used on all or no bindings of a recursive group"
+     
 -- | Make the vectorised version of this top level binder, and add the mapping
 --   between it and the original to the state. For some binder @foo@ the vectorised
 --   version is @$v_foo@
 --
---   NOTE: vectTopBinder *MUST* be lazy in inline and expr because of how it is
---   used inside of fixV in vectTopBind
+--   NOTE: 'vectTopBinder' *MUST* be lazy in inline and expr because of how it is
+--   used inside of 'fixV' in 'vectTopBind'.
 --
 vectTopBinder :: Var      -- ^ Name of the binding.
               -> Inline   -- ^ Whether it should be inlined, used to annotate it.
diff --git a/compiler/vectorise/Vectorise/Builtins/Prelude.hs b/compiler/vectorise/Vectorise/Builtins/Prelude.hs
index 51b3d14054..a59f9369aa 100644
--- a/compiler/vectorise/Vectorise/Builtins/Prelude.hs
+++ b/compiler/vectorise/Vectorise/Builtins/Prelude.hs
@@ -27,7 +27,7 @@ preludeVars :: Modules
 preludeVars (Modules { dph_Combinators    = _dph_Combinators
                      , dph_Prelude_Int    = dph_Prelude_Int
                      , dph_Prelude_Word8  = dph_Prelude_Word8
-                     , dph_Prelude_Double = dph_Prelude_Double
+                     -- , dph_Prelude_Double = dph_Prelude_Double
                      , dph_Prelude_Bool   = dph_Prelude_Bool 
                      })
 
@@ -50,11 +50,11 @@ preludeVars (Modules { dph_Combinators    = _dph_Combinators
     , mk' dph_Prelude_Word8 "toInt"   "toIntV"
     ]
 
-    ++ vars_Ord        dph_Prelude_Double
-    ++ vars_Num        dph_Prelude_Double
-    ++ vars_Fractional dph_Prelude_Double
-    ++ vars_Floating   dph_Prelude_Double
-    ++ vars_RealFrac   dph_Prelude_Double
+    -- ++ vars_Ord        dph_Prelude_Double
+    -- ++ vars_Num        dph_Prelude_Double
+    -- ++ vars_Fractional dph_Prelude_Double
+    -- ++ vars_Floating   dph_Prelude_Double
+    -- ++ vars_RealFrac   dph_Prelude_Double
     ++
     [ mk dph_Prelude_Bool  (fsLit "andP")  dph_Prelude_Bool (fsLit "andPA")
     , mk dph_Prelude_Bool  (fsLit "orP")   dph_Prelude_Bool (fsLit "orPA")
@@ -92,40 +92,40 @@ preludeVars (Modules { dph_Combinators    = _dph_Combinators
        , mk' mod "productP" "productPA"
        ]
 
-    vars_Fractional mod 
-     = [ mk' mod "/"     "divideV"
-       , mk' mod "recip" "recipV"
-       ]
-
-    vars_Floating mod 
-     = [ mk' mod "pi"      "pi"
-       , mk' mod "exp"     "expV"
-       , mk' mod "sqrt"    "sqrtV"
-       , mk' mod "log"     "logV"
-       , mk' mod "sin"     "sinV"
-       , mk' mod "tan"     "tanV"
-       , mk' mod "cos"     "cosV"
-       , mk' mod "asin"    "asinV"
-       , mk' mod "atan"    "atanV"
-       , mk' mod "acos"    "acosV"
-       , mk' mod "sinh"    "sinhV"
-       , mk' mod "tanh"    "tanhV"
-       , mk' mod "cosh"    "coshV"
-       , mk' mod "asinh"   "asinhV"
-       , mk' mod "atanh"   "atanhV"
-       , mk' mod "acosh"   "acoshV"
-       , mk' mod "**"      "powV"
-       , mk' mod "logBase" "logBaseV"
-       ]
-
-    vars_RealFrac mod
-     = [ mk' mod "fromInt"  "fromIntV"
-       , mk' mod "truncate" "truncateV"
-       , mk' mod "round"    "roundV"
-       , mk' mod "ceiling"  "ceilingV"
-       , mk' mod "floor"    "floorV"
-       ]
-
+    -- vars_Fractional mod 
+    --  = [ mk' mod "/"     "divideV"
+    --    , mk' mod "recip" "recipV"
+    --    ]
+    -- 
+    -- vars_Floating mod 
+    --  = [ mk' mod "pi"      "pi"
+    --    , mk' mod "exp"     "expV"
+    --    , mk' mod "sqrt"    "sqrtV"
+    --    , mk' mod "log"     "logV"
+    --    , mk' mod "sin"     "sinV"
+    --    , mk' mod "tan"     "tanV"
+    --    , mk' mod "cos"     "cosV"
+    --    , mk' mod "asin"    "asinV"
+    --    , mk' mod "atan"    "atanV"
+    --    , mk' mod "acos"    "acosV"
+    --    , mk' mod "sinh"    "sinhV"
+    --    , mk' mod "tanh"    "tanhV"
+    --    , mk' mod "cosh"    "coshV"
+    --    , mk' mod "asinh"   "asinhV"
+    --    , mk' mod "atanh"   "atanhV"
+    --    , mk' mod "acosh"   "acoshV"
+    --    , mk' mod "**"      "powV"
+    --    , mk' mod "logBase" "logBaseV"
+    --    ]
+    -- 
+    -- vars_RealFrac mod
+    --  = [ mk' mod "fromInt"  "fromIntV"
+    --    , mk' mod "truncate" "truncateV"
+    --    , mk' mod "round"    "roundV"
+    --    , mk' mod "ceiling"  "ceilingV"
+    --    , mk' mod "floor"    "floorV"
+    --    ]
+    -- 
 preludeScalars :: Modules -> [(Module, FastString)]
 preludeScalars (Modules { dph_Prelude_Int    = dph_Prelude_Int
                         , dph_Prelude_Word8  = dph_Prelude_Word8
diff --git a/compiler/vectorise/Vectorise/Env.hs b/compiler/vectorise/Vectorise/Env.hs
index 780a07fefc..97bb5aef69 100644
--- a/compiler/vectorise/Vectorise/Env.hs
+++ b/compiler/vectorise/Vectorise/Env.hs
@@ -95,6 +95,10 @@ data GlobalEnv
         , global_scalar_tycons  :: NameSet
           -- ^Type constructors whose values can only contain scalar data.  Scalar code may only
           -- operate on such data.
+        
+        , global_novect_vars    :: VarSet
+          -- ^Variables that are not vectorised.  (They may be referenced in the right-hand sides
+          -- of vectorisation declarations, though.)
 
         , global_exported_vars  :: VarEnv (Var, Var)
           -- ^Exported variables which have a vectorised version.
@@ -134,6 +138,7 @@ initGlobalEnv info vectDecls instEnvs famInstEnvs
   , global_vect_decls    = mkVarEnv vects
   , global_scalar_vars   = vectInfoScalarVars   info `extendVarSetList` scalars
   , global_scalar_tycons = vectInfoScalarTyCons info
+  , global_novect_vars   = mkVarSet novects
   , global_exported_vars = emptyVarEnv
   , global_tycons        = mapNameEnv snd $ vectInfoTyCon info
   , global_datacons      = mapNameEnv snd $ vectInfoDataCon info
@@ -147,6 +152,7 @@ initGlobalEnv info vectDecls instEnvs famInstEnvs
   where
     vects   = [(var, (varType var, exp)) | Vect var (Just exp) <- vectDecls]
     scalars = [var                       | Vect var Nothing    <- vectDecls]
+    novects = [var                       | NoVect var          <- vectDecls]
 
 
 -- Operators on Global Environments -------------------------------------------
diff --git a/compiler/vectorise/Vectorise/Monad.hs b/compiler/vectorise/Vectorise/Monad.hs
index e2933cdc6b..73cba88a3b 100644
--- a/compiler/vectorise/Vectorise/Monad.hs
+++ b/compiler/vectorise/Vectorise/Monad.hs
@@ -81,6 +81,7 @@ initV hsc_env guts info thing_inside
            ; builtin_pas <- initBuiltinPAs builtins instEnvs
 
                -- construct the initial global environment
+           ; let thing_inside' = traceVt "VectDecls" (ppr (mg_vect_decls guts)) >> thing_inside
            ; let genv = extendImportedVarsEnv builtin_vars
                         . extendScalars       builtin_scalars
                         . extendTyConsEnv     builtin_tycons
@@ -91,7 +92,7 @@ initV hsc_env guts info thing_inside
                         $ initGlobalEnv info (mg_vect_decls guts) instEnvs famInstEnvs
  
                -- perform vectorisation
-           ; r <- runVM thing_inside builtins genv emptyLocalEnv
+           ; r <- runVM thing_inside' builtins genv emptyLocalEnv
            ; case r of
                Yes genv _ x -> return $ Just (new_info genv, x)
                No           -> return Nothing
diff --git a/compiler/vectorise/Vectorise/Monad/Global.hs b/compiler/vectorise/Vectorise/Monad/Global.hs
index 632845f310..e471ebbc03 100644
--- a/compiler/vectorise/Vectorise/Monad/Global.hs
+++ b/compiler/vectorise/Vectorise/Monad/Global.hs
@@ -1,34 +1,34 @@
 
 module Vectorise.Monad.Global (
-	readGEnv,
-	setGEnv,
-	updGEnv,
-	
+  readGEnv,
+  setGEnv,
+  updGEnv,
+  
   -- * Vars
   defGlobalVar,
   
   -- * Vectorisation declarations
-  lookupVectDecl,
+  lookupVectDecl, noVectDecl, 
   
   -- * Scalars
   globalScalars, isGlobalScalar,
-	
-	-- * TyCons
-	lookupTyCon,
-	lookupBoxedTyCon,
-	defTyCon,
-	
-	-- * Datacons
-	lookupDataCon,
-	defDataCon,
-	
-	-- * PA Dictionaries
-	lookupTyConPA,
-	defTyConPA,
-	defTyConPAs,
-	
-	-- * PR Dictionaries
-	lookupTyConPR
+  
+  -- * TyCons
+  lookupTyCon,
+  lookupBoxedTyCon,
+  defTyCon,
+  
+  -- * Datacons
+  lookupDataCon,
+  defDataCon,
+  
+  -- * PA Dictionaries
+  lookupTyConPA,
+  defTyConPA,
+  defTyConPAs,
+  
+  -- * PR Dictionaries
+  lookupTyConPR
 ) where
 
 import Vectorise.Monad.Base
@@ -45,23 +45,27 @@ import VarSet
 
 
 -- Global Environment ---------------------------------------------------------
--- | Project something from the global environment.
+
+-- |Project something from the global environment.
+--
 readGEnv :: (GlobalEnv -> a) -> VM a
 readGEnv f	= VM $ \_ genv lenv -> return (Yes genv lenv (f genv))
 
-
--- | Set the value of the global environment.
+-- |Set the value of the global environment.
+--
 setGEnv :: GlobalEnv -> VM ()
 setGEnv genv	= VM $ \_ _ lenv -> return (Yes genv lenv ())
 
-
--- | Update the global environment using the provided function.
+-- |Update the global environment using the provided function.
+--
 updGEnv :: (GlobalEnv -> GlobalEnv) -> VM ()
 updGEnv f	= VM $ \_ genv lenv -> return (Yes (f genv) lenv ())
 
 
 -- Vars -----------------------------------------------------------------------
--- | Add a mapping between a global var and its vectorised version to the state.
+
+-- |Add a mapping between a global var and its vectorised version to the state.
+--
 defGlobalVar :: Var -> Var -> VM ()
 defGlobalVar v v' = updGEnv $ \env ->
   env { global_vars = extendVarEnv (global_vars env) v v'
@@ -79,6 +83,11 @@ defGlobalVar v v' = updGEnv $ \env ->
 lookupVectDecl :: Var -> VM (Maybe (Type, CoreExpr))
 lookupVectDecl var = readGEnv $ \env -> lookupVarEnv (global_vect_decls env) var
 
+-- |Check whether a variable has a 'NOVECTORISE' declaration.
+--
+noVectDecl :: Var -> VM Bool
+noVectDecl var = readGEnv $ \env -> elemVarSet var (global_novect_vars env)
+
 
 -- Scalars --------------------------------------------------------------------
 
@@ -94,7 +103,9 @@ isGlobalScalar var = readGEnv $ \env -> elemVarSet var (global_scalar_vars env)
 
 
 -- TyCons ---------------------------------------------------------------------
--- | Lookup the vectorised version of a `TyCon` from the global environment.
+
+-- |Lookup the vectorised version of a `TyCon` from the global environment.
+--
 lookupTyCon :: TyCon -> VM (Maybe TyCon)
 lookupTyCon tc
   | isUnLiftedTyCon tc || isTupleTyCon tc
@@ -103,14 +114,12 @@ lookupTyCon tc
   | otherwise 
   = readGEnv $ \env -> lookupNameEnv (global_tycons env) (tyConName tc)
 
-
 -- | Lookup the vectorised version of a boxed `TyCon` from the global environment.
 lookupBoxedTyCon :: TyCon -> VM (Maybe TyCon)
 lookupBoxedTyCon tc 
 	= readGEnv $ \env -> lookupNameEnv (global_boxed_tycons env)
                                            (tyConName tc)
 
-
 -- | Add a mapping between plain and vectorised `TyCon`s to the global environment.
 defTyCon :: TyCon -> TyCon -> VM ()
 defTyCon tc tc' = updGEnv $ \env ->
@@ -118,6 +127,7 @@ defTyCon tc tc' = updGEnv $ \env ->
 
 
 -- DataCons -------------------------------------------------------------------
+
 -- | Lookup the vectorised version of a `DataCon` from the global environment.
 lookupDataCon :: DataCon -> VM (Maybe DataCon)
 lookupDataCon dc