Added a VECTORISE pragma

- Added a pragma {-# VECTORISE var = exp #-} that prevents
  the vectoriser from vectorising the definition of 'var'.
  Instead it uses the binding '$v_var = exp' to vectorise
  'var'.  The vectoriser checks that the Core type of 'exp'
  matches the vectorised Core type of 'var'.  (It would be
  quite complicated to perform that check in the type checker
  as the vectorisation of a type needs the state of the VM
  monad.)
- Added parts of a related VECTORISE SCALAR pragma
- Documented -ddump-vect
- Added -ddump-vt-trace
- Some clean up

1 files changed, 12 insertions, 17 deletions

diff --git a/compiler/vectorise/Vectorise/Exp.hs b/compiler/vectorise/Vectorise/Exp.hs
index 9cd34e3ac3..569057e5e8 100644
--- a/compiler/vectorise/Vectorise/Exp.hs
+++ b/compiler/vectorise/Vectorise/Exp.hs
@@ -33,17 +33,15 @@ import Data.List
 
 
 -- | Vectorise a polymorphic expression.
-vectPolyExpr 
-	:: Bool 		-- ^ When vectorising the RHS of a binding, whether that
-			  	    --   binding is a loop breaker.
-	-> [Var] 			
-	-> CoreExprWithFVs
-	-> VM (Inline, Bool, VExpr)
-
+--
+vectPolyExpr :: Bool 		-- ^ When vectorising the RHS of a binding, whether that
+			  	              --   binding is a loop breaker.
+	           -> [Var] 			
+	           -> CoreExprWithFVs
+	           -> VM (Inline, Bool, VExpr)
 vectPolyExpr loop_breaker recFns (_, AnnNote note expr)
  = do (inline, isScalarFn, expr') <- vectPolyExpr loop_breaker recFns expr
       return (inline, isScalarFn, vNote note expr')
-
 vectPolyExpr loop_breaker recFns expr
  = do
       arity <- polyArity tvs
@@ -148,22 +146,19 @@ onlyIfV (isEmptyVarSet fvs) (vectScalarLam bs $ deAnnotate body)
 
 vectExpr e = cantVectorise "Can't vectorise expression (vectExpr)" (ppr $ deAnnotate e)
 
-
 -- | Vectorise an expression with an outer lambda abstraction.
-vectFnExpr 
-	:: Bool 		-- ^ When the RHS of a binding, whether that binding should be inlined.
-	-> Bool 		-- ^ Whether the binding is a loop breaker.
-	-> [Var]
-	-> CoreExprWithFVs 	-- ^ Expression to vectorise. Must have an outer `AnnLam`.
-	-> VM (Inline, Bool, VExpr)
-
+--
+vectFnExpr :: Bool             -- ^ When the RHS of a binding, whether that binding should be inlined.
+           -> Bool             -- ^ Whether the binding is a loop breaker.
+           -> [Var]
+           -> CoreExprWithFVs  -- ^ Expression to vectorise. Must have an outer `AnnLam`.
+           -> VM (Inline, Bool, VExpr)
 vectFnExpr inline loop_breaker recFns e@(fvs, AnnLam bndr _)
   | isId bndr = onlyIfV True -- (isEmptyVarSet fvs)  -- we check for free variables later. TODO: clean up
                         (mark DontInline True . vectScalarLam bs recFns $ deAnnotate body)
                 `orElseV` mark inlineMe False (vectLam inline loop_breaker fvs bs body)
   where
     (bs,body) = collectAnnValBinders e
-
 vectFnExpr _ _ _  e = mark DontInline False $ vectExpr e
 
 mark :: Inline -> Bool -> VM a -> VM (Inline, Bool, a)