X-Git-Url: https://git.stderr.nl/gitweb?a=blobdiff_plain;f=c%CE%BBash%2FCLasH%2FNormalize.hs;h=cd3ba5817ca1e04384185d74dd7e50f113059d61;hb=0e3e9200536bf038c77f43e43a678d408afee466;hp=6a4825d42406343c5b6eb94191fdaf5b4ed554e0;hpb=7d60f355a116d10adef0a66370d8bfa6a859e8b2;p=matthijs%2Fmaster-project%2Fc%CE%BBash.git

diff --git "a/c\316\273ash/CLasH/Normalize.hs" "b/c\316\273ash/CLasH/Normalize.hs"
index 6a4825d..cd3ba58 100644
--- "a/c\316\273ash/CLasH/Normalize.hs"
+++ "b/c\316\273ash/CLasH/Normalize.hs"
@@ -123,15 +123,12 @@ letderec expr@(Let (Rec binds) res) = case liftable of
   -- Nothing is liftable, just return
   [] -> return expr
   -- Something can be lifted, generate a new let expression
-  _ -> change $ MkCore.mkCoreLets newbinds res
+  _ -> change $ mkNonRecLets liftable (Let (Rec nonliftable) res)
   where
     -- Make a list of all the binders bound in this recursive let
     bndrs = map fst binds
     -- See which bindings are liftable
     (liftable, nonliftable) = List.partition canlift binds
-    -- Create nonrec bindings for each liftable binding and a single recursive
-    -- binding for all others
-    newbinds = (map (uncurry NonRec) liftable) ++ [Rec nonliftable]
     -- Any expression that does not use any of the binders in this recursive let
     -- can be lifted into a nonrec let. It can't use its own binder either,
     -- since that would mean the binding is self-recursive and should be in a
@@ -185,12 +182,23 @@ letflat expr = return expr
 -- Perform this transform everywhere
 letflattop = everywhere ("letflat", letflat)
 
+--------------------------------
+-- empty let removal
+--------------------------------
+-- Remove empty (recursive) lets
+letremove, letremovetop :: Transform
+letremove (Let (Rec []) res) = change $ res
+-- Leave all other expressions unchanged
+letremove expr = return expr
+-- Perform this transform everywhere
+letremovetop = everywhere ("letremove", letremove)
+
 --------------------------------
 -- Simple let binding removal
 --------------------------------
 -- Remove a = b bindings from let expressions everywhere
-letremovetop :: Transform
-letremovetop = everywhere ("letremove", inlinebind (\(b, e) -> Trans.lift $ is_local_var e))
+letremovesimpletop :: Transform
+letremovesimpletop = everywhere ("letremovesimple", inlinebind (\(b, e) -> Trans.lift $ is_local_var e))
 
 --------------------------------
 -- Unused let binding removal
@@ -217,9 +225,10 @@ letremoveunusedtop = everywhere ("letremoveunused", letremoveunused)
 -- TODO: We would very much like to use GHC's CSE module for this, but that
 -- doesn't track if something changed or not, so we can't use it properly.
 letmerge, letmergetop :: Transform
-letmerge expr@(Let (Rec binds) res) = do
+letmerge expr@(Let _ _) = do
+  let (binds, res) = flattenLets expr
   binds' <- domerge binds
-  return (Let (Rec binds') res)
+  return $ mkNonRecLets binds' res
   where
     domerge :: [(CoreBndr, CoreExpr)] -> TransformMonad [(CoreBndr, CoreExpr)]
     domerge [] = return []
@@ -556,7 +565,7 @@ funextracttop = everywhere ("funextract", funextract)
 
 
 -- What transforms to run?
-transforms = [argproptop, funextracttop, etatop, betatop, castproptop, letremovetop, letderectop, letsimpltop, letflattop, scrutsimpltop, casesimpltop, caseremovetop, inlinenonreptop, appsimpltop, letmergetop, letremoveunusedtop, castsimpltop]
+transforms = [argproptop, funextracttop, etatop, betatop, castproptop, letremovesimpletop, letderectop, letremovetop, letsimpltop, letflattop, scrutsimpltop, casesimpltop, caseremovetop, inlinenonreptop, appsimpltop, letmergetop, letremoveunusedtop, castsimpltop]
 
 -- | Returns the normalized version of the given function.
 getNormalized ::
@@ -609,18 +618,3 @@ splitNormalized expr = (args, binds, res)
     res = case resexpr of 
       (Var x) -> x
       _ -> error $ "Normalize.splitNormalized: Not in normal form: " ++ pprString expr ++ "\n"
-
--- | Flattens nested lets into a single list of bindings. The expression
---   passed does not have to be a let expression, if it isn't an empty list of
---   bindings is returned.
-flattenLets ::
-  CoreExpr -- ^ The expression to flatten.
-  -> ([Binding], CoreExpr) -- ^ The bindings and resulting expression.
-flattenLets (Let binds expr) = 
-  (bindings ++ bindings', expr')
-  where
-    -- Recursively flatten the contained expression
-    (bindings', expr') =flattenLets expr
-    -- Flatten our own bindings to remove the Rec / NonRec constructors
-    bindings = CoreSyn.flattenBinds [binds]
-flattenLets expr = ([], expr)