Make letsimpl work on and generate a non-recursive let.

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

diff --git a/cλash/CLasH/Normalize.hs b/cλash/CLasH/Normalize.hs
index 9828d5ceea96704f92b979766dd06be5bfcc7523..dd8244d4d7d4be4d1e90d9a1c78d7f70fb925c09 100644 (file)
--- a/cλash/CLasH/Normalize.hs
+++ b/cλash/CLasH/Normalize.hs
@@ -107,7 +107,7 @@ castsimpl expr@(Cast val ty) = do
       -- Generate a binder for the expression
       id <- Trans.lift $ mkBinderFor val "castval"
       -- Extract the expression
-      change $ Let (Rec [(id, val)]) (Cast (Var id) ty)
+      change $ Let (NonRec id val) (Cast (Var id) ty)
     else
       return expr
 -- Leave all other expressions unchanged
@@ -148,7 +148,7 @@ letderectop = everywhere ("letderec", letderec)
 letsimpl, letsimpltop :: Transform
 -- Put the "in ..." value of a let in its own binding, but not when the
 -- expression is already a local variable, or not representable (to prevent loops with inlinenonrep).
-letsimpl expr@(Let (Rec binds) res) = do
+letsimpl expr@(Let binds res) = do
   repr <- isRepr res
   local_var <- Trans.lift $ is_local_var res
   if not local_var && repr
@@ -156,8 +156,7 @@ letsimpl expr@(Let (Rec binds) res) = do
       -- If the result is not a local var already (to prevent loops with
       -- ourselves), extract it.
       id <- Trans.lift $ mkBinderFor res "foo"
-      let bind = (id, res)
-      change $ Let (Rec (bind:binds)) (Var id)
+      change $ Let binds (Let (NonRec id  res) (Var id))
     else
       -- If the result is already a local var, don't extract it.
       return expr
@@ -280,7 +279,7 @@ scrutsimpl expr@(Case scrut b ty alts) = do
   if repr
     then do
       id <- Trans.lift $ mkBinderFor scrut "scrut"
-      change $ Let (Rec [(id, scrut)]) (Case (Var id) b ty alts)
+      change $ Let (NonRec id scrut) (Case (Var id) b ty alts)
     else
       return expr
 -- Leave all other expressions unchanged
@@ -414,7 +413,7 @@ appsimpl expr@(App f arg) = do
   if repr && not local_var
     then do -- Extract representable arguments
       id <- Trans.lift $ mkBinderFor arg "arg"
-      change $ Let (Rec [(id, arg)]) (App f (Var id))
+      change $ Let (NonRec id arg) (App f (Var id))
     else -- Leave non-representable arguments unchanged
       return expr
 -- Leave all other expressions unchanged
@@ -587,15 +586,11 @@ normalizeExpr ::
   -> TranslatorSession CoreSyn.CoreExpr -- ^ The normalized expression
 
 normalizeExpr what expr = do
-      -- Introduce an empty Let at the top level, so there will always be
-      -- a let in the expression (none of the transformations will remove
-      -- the last let).
-      let expr' = Let (Rec []) expr
       -- Normalize this expression
-      trace (what ++ " before normalization:\n\n" ++ showSDoc ( ppr expr' ) ++ "\n") $ return ()
-      expr'' <- dotransforms transforms expr'
-      trace ("\n" ++ what ++ " after normalization:\n\n" ++ showSDoc ( ppr expr'')) $ return ()
-      return expr''
+      trace (what ++ " before normalization:\n\n" ++ showSDoc ( ppr expr ) ++ "\n") $ return ()
+      expr' <- dotransforms transforms expr
+      trace ("\n" ++ what ++ " after normalization:\n\n" ++ showSDoc ( ppr expr')) $ return ()
+      return expr'
 
 -- | Get the value that is bound to the given binder at top level. Fails when
 --   there is no such binding.