diff --git a/Feldspar/C/feldspar_c99.c b/Feldspar/C/feldspar_c99.c
--- a/Feldspar/C/feldspar_c99.c
+++ b/Feldspar/C/feldspar_c99.c
@@ -876,7 +876,7 @@
         exit (8);
     }
     fprintf(trace_log_file, 
-          "The logging started at %02d-%02d-%04d %02d:%02d:%02d.\n", 
+          "Logging started at %02d-%02d-%04d %02d:%02d:%02d.\n", 
           lt.wDay, lt.wMonth, lt.wYear, lt.wHour, lt.wMinute, lt.wSecond);
     fflush(trace_log_file);
     trace_start_time = GetTickCount();
@@ -908,7 +908,7 @@
         exit (8);
     }
     strftime(timestr, 80, "%d-%b-%Y %H:%M:%S", timeinfo);
-    fprintf(trace_log_file, "The logging started at %s.\n", timestr);
+    fprintf(trace_log_file, "Logging started at %s.\n", timestr);
     fflush(trace_log_file);
     gettimeofday(&trace_start_time, NULL);
 }
@@ -931,7 +931,7 @@
 
 void traceEnd()
 {
-    fprintf(trace_log_file, "The logging finished.\n");
+    fprintf(trace_log_file, "Logging finished.\n");
     fclose(trace_log_file);
 }
 
diff --git a/Feldspar/C/feldspar_tic64x.c b/Feldspar/C/feldspar_tic64x.c
--- a/Feldspar/C/feldspar_tic64x.c
+++ b/Feldspar/C/feldspar_tic64x.c
@@ -973,7 +973,7 @@
         exit (8);
     }
     strftime(timestr, 80, "%d-%b-%Y %H:%M:%S", timeinfo);
-    fprintf(trace_log_file, "The logging started at %s.\n", timestr);
+    fprintf(trace_log_file, "Logging started at %s.\n", timestr);
     fflush(trace_log_file);
     trace_start_time = time(NULL);
 }
@@ -985,7 +985,7 @@
 
 void traceEnd()
 {
-    fprintf(trace_log_file, "The logging finished.\n");
+    fprintf(trace_log_file, "Logging finished.\n");
     fclose(trace_log_file);
 }
 
diff --git a/Feldspar/Compiler/Plugins/BackwardPropagation.hs b/Feldspar/Compiler/Plugins/BackwardPropagation.hs
--- a/Feldspar/Compiler/Plugins/BackwardPropagation.hs
+++ b/Feldspar/Compiler/Plugins/BackwardPropagation.hs
@@ -37,6 +37,7 @@
 import Feldspar.Compiler.Plugins.PropagationUtils
 import qualified Data.Map as Map
 import qualified Data.List as List
+import qualified Data.Set as Set
 import Data.Maybe
 import Feldspar.Compiler.Options
 
@@ -139,7 +140,7 @@
     transformBlock self d origBlock u = Block {
             blockDeclarations = recursivelyTransformedBlockDeclarations u,
             blockInstructions = recursivelyTransformedBlockInstructions u,
-            blockSemInf = unChain $ checkInDeclatation origBlock $ upwardsInfoFromBlockInstructions u
+            blockSemInf = checkInDeclatation origBlock $ upwardsInfoFromBlockInstructions u
         } 
     transformPrimitiveProgramInProgram self d origPrimitive u = PrimitiveProgram $ Primitive {
             primitiveInstruction = recursivelyTransformedPrimitiveInstruction u,
@@ -232,30 +233,48 @@
     type To PropagationTransform = ()
     type Downwards PropagationTransform = [(VariableData, LeftValueData ())]
     type Upwards PropagationTransform = ()
-    downwardsBlock self d origBlock = foldl addChain (blockSemInf origBlock) d
+    downwardsBlock self d origBlock = unChain $ foldl addChain (blockSemInf origBlock) d
     downwardsLocalDeclaration self d origLocDecl = []
-    transformBlock self d orig u = delUnusedDecl (map fst $ foldl addChain (blockSemInf orig) d) orig (recursivelyTransformedBlockDeclarations u) (recursivelyTransformedBlockInstructions u)
-    transformPrimitiveProgramInProgram self d origPrimitive u =
-        case primitiveSemInf origPrimitive of
-            Nothing -> makedPrim
-            Just (var,outD,_)
-                | List.elem (var,outD) d || ((List.elem (getLvName outD) $ map fst d) && (List.elem var $ map fst d) ) -> EmptyProgram $ Empty ()
-                | otherwise -> makedPrim
+    transformBlock self d orig u = delUnusedDecl (map fst $ downwardsBlock self d orig) orig (recursivelyTransformedBlockDeclarations u) (recursivelyTransformedBlockInstructions u)
+    transformPrimitiveProgramInProgram self d origPrimitive u = 
+        case isIdentity $ instructionData newInstr of
+            True -> EmptyProgram $ Empty ()
+            False -> makedPrim
         where
-              makedPrim = PrimitiveProgram $ Primitive {
-                primitiveInstruction = recursivelyTransformedPrimitiveInstruction u,
+            makedPrim = PrimitiveProgram $ Primitive {
+                primitiveInstruction = newInstr,
                 primitiveSemInf =()
             }
-    transformVariableLeftValueInLeftValue self d origVar = case List.find (\(a,b) -> a == {-newVar-} variableData origVar) d of
+            newInstr = recursivelyTransformedPrimitiveInstruction u
+            isIdentity (AssignmentInstruction a) = isIdentity' (assignmentRhs a) (assignmentLhs a)
+            isIdentity (ProcedureCallInstruction p)
+                | nameOfProcedureToCall p == "copy" = case map actualParameterData $ actualParametersOfProcedureToCall p of
+                    [InputActualParameter i,OutputActualParameter o] -> isIdentity' i o
+                    _ -> False
+                | otherwise = False
+            isIdentity' e l = List.elem (expressionData e) [LeftValueExpression $ swapArrayIndex l, LeftValueExpression l]
+            swapArrayIndex :: LeftValue () -> LeftValue ()
+            swapArrayIndex l = setIndex $ (\(a,b)->(a,reverse b)) $ getIndex l
+            getIndex :: LeftValue () -> (Variable (), [Expression ()])
+            getIndex lv = getIndex2 $ leftValueData lv
+            getIndex2 (VariableLeftValue v) = (v,[])
+            getIndex2 (ArrayElemReferenceLeftValue a) = (fst $ getIndex $ arrayName a, (arrayIndex a):(snd $ getIndex $ arrayName a))            
+            setIndex :: (Variable (), [Expression ()]) -> LeftValue ()
+            setIndex x = LeftValue (setIndex2 x) ()
+            setIndex2 (v,[]) = VariableLeftValue v
+            setIndex2 (v,(x:xs)) = ArrayElemReferenceLeftValue $ ArrayElemReference (setIndex (v,xs)) x ()
+    transformVariableLeftValueInLeftValue self d origVar = case List.find (\(a,b) -> a == variableData origVar) d of
             Nothing -> VariableLeftValue $ origVar {
                     variableSemInf = ()
                 }
             Just (var,out) -> out
-        --where
-        --    newVar = variableData $ recursivelyTransformedVariableLeftValueContents u
-
+            
 unChain :: [(VariableData, LeftValueData ())] -> [(VariableData, LeftValueData ())]
-unChain s = foldl addChain [] s
+unChain s = unchain' s where
+    unchain' s
+        | s == unchain'' s = s
+        | otherwise = unchain'' s
+    unchain'' s = foldl addChain [] s
 
 addChain :: [(VariableData, LeftValueData ())] -> (VariableData, LeftValueData ()) -> [(VariableData, LeftValueData ())]
 addChain [] pair = [pair]
diff --git a/feldspar-compiler.cabal b/feldspar-compiler.cabal
--- a/feldspar-compiler.cabal
+++ b/feldspar-compiler.cabal
@@ -1,5 +1,5 @@
 name:           feldspar-compiler
-version:        0.3
+version:        0.3.1
 cabal-version:  >= 1.6
 build-type:     Simple
 license:        BSD3
@@ -47,7 +47,7 @@
     Feldspar.Fs2dot
 
   build-depends:
-    feldspar-language == 0.3,
+    feldspar-language == 0.3.1,
     base >= 4 && < 4.3,
     containers,
     haskell-src-exts,