Merge git://github.com/darchon/clash into cλash

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

diff --git a/Normalize.hs b/Normalize.hs
index cceefc0cf7baf76c4135da6ef12cc7f9c5922988..747a95b0c6eccd898bfbd12e0bec80f33a0910ae 100644 (file)
--- a/Normalize.hs
+++ b/Normalize.hs
@@ -43,7 +43,6 @@ import Pretty
 -- η abstraction
 --------------------------------
 eta, etatop :: Transform
-eta expr | is_fun expr && not (is_lam expr) = do
 eta expr | is_fun expr && not (is_lam expr) = do
   let arg_ty = (fst . Type.splitFunTy . CoreUtils.exprType) expr
   id <- mkInternalVar "param" arg_ty
@@ -70,6 +69,20 @@ beta expr = return expr
 -- Perform this transform everywhere
 betatop = everywhere ("beta", beta)
 
+--------------------------------
+-- Cast propagation
+--------------------------------
+-- Try to move casts as much downward as possible.
+castprop, castproptop :: Transform
+castprop (Cast (Let binds expr) ty) = change $ Let binds (Cast expr ty)
+castprop expr@(Cast (Case scrut b _ alts) ty) = change (Case scrut b ty alts')
+  where
+    alts' = map (\(con, bndrs, expr) -> (con, bndrs, (Cast expr ty))) alts
+-- Leave all other expressions unchanged
+castprop expr = return expr
+-- Perform this transform everywhere
+castproptop = everywhere ("castprop", castprop)
+
 --------------------------------
 -- let recursification
 --------------------------------
@@ -408,7 +421,7 @@ funproptop = everywhere ("funprop", funprop)
 
 
 -- What transforms to run?
-transforms = [typeproptop, funproptop, etatop, betatop, letremovetop, letrectop, letsimpltop, letflattop, casewildtop, scrutsimpltop, casevalsimpltop, caseremovetop, inlinefuntop, appsimpltop]
+transforms = [typeproptop, funproptop, etatop, betatop, castproptop, letremovetop, letrectop, letsimpltop, letflattop, casewildtop, scrutsimpltop, casevalsimpltop, caseremovetop, inlinefuntop, appsimpltop]
 
 -- Turns the given bind into VHDL
 normalizeModule ::