Disable letmerge.

[matthijs/master-project/cλash.git] / cλash / CLasH / Normalize.hs

diff --git a/cλash/CLasH/Normalize.hs b/cλash/CLasH/Normalize.hs
index a7223e3d8d0433ca55f21a3c5e7a729afb63a4d2..192ed55cf0500c1655fb9b1adba6c3a79512d596 100644 (file)
--- a/cλash/CLasH/Normalize.hs
+++ b/cλash/CLasH/Normalize.hs
@@ -248,13 +248,17 @@ letremovesimpletop = everywhere ("letremovesimple", inlinebind (\(b, e) -> Trans
 -- Unused let binding removal
 --------------------------------
 letremoveunused, letremoveunusedtop :: Transform
-letremoveunused expr@(Let _ _) = do
+letremoveunused expr@(Let (NonRec b bound) res) = do
+  let used = expr_uses_binders [b] res
+  if used
+    then return expr
+    else change res
+letremoveunused expr@(Let (Rec binds) res) = do
   -- Filter out all unused binds.
   let binds' = filter dobind binds
   -- Only set the changed flag if binds got removed
-  changeif (length binds' /= length binds) (mkNonRecLets binds' res)
+  changeif (length binds' /= length binds) (Let (Rec binds') res)
     where
-      (binds, res) = flattenLets expr
       bound_exprs = map snd binds
       -- For each bind check if the bind is used by res or any of the bound
       -- expressions
@@ -263,6 +267,7 @@ letremoveunused expr@(Let _ _) = do
 letremoveunused expr = return expr
 letremoveunusedtop = everywhere ("letremoveunused", letremoveunused)
 
+{-
 --------------------------------
 -- Identical let binding merging
 --------------------------------
@@ -293,7 +298,8 @@ letmerge expr@(Let _ _) = do
 -- Leave all other expressions unchanged
 letmerge expr = return expr
 letmergetop = everywhere ("letmerge", letmerge)
-    
+-}
+
 --------------------------------
 -- Function inlining
 --------------------------------
@@ -610,7 +616,7 @@ funextracttop = everywhere ("funextract", funextract)
 
 
 -- What transforms to run?
-transforms = [argproptop, funextracttop, etatop, betatop, castproptop, letremovesimpletop, letderectop, letremovetop, letsimpltop, letflattop, scrutsimpltop, casesimpltop, caseremovetop, inlinenonreptop, appsimpltop, letmergetop, letremoveunusedtop, castsimpltop, lambdasimpltop]
+transforms = [argproptop, funextracttop, etatop, betatop, castproptop, letremovesimpletop, letderectop, letremovetop, letsimpltop, letflattop, scrutsimpltop, casesimpltop, caseremovetop, inlinenonreptop, appsimpltop, letremoveunusedtop, castsimpltop, lambdasimpltop]
 
 -- | Returns the normalized version of the given function.
 getNormalized ::