No real need to check whether expressions have already been marked

compiler/frontend/src/org/jetbrains/jet/lang/cfg/JetControlFlowProcessor.java

@@ -64,7 +64,6 @@ public class JetControlFlowProcessor {
 
     private final JetControlFlowBuilder builder;
     private final BindingTrace trace;
-    private final Set<PsiElement> marked = new HashSet<PsiElement>();
 
     public JetControlFlowProcessor(BindingTrace trace) {
         this.builder = new JetControlFlowInstructionsGenerator();
@@ -142,7 +141,6 @@ public class JetControlFlowProcessor {
         }
 
         private void mark(JetElement element) {
-            if (!marked.add(element)) return;
             builder.mark(element);
         }
 

compiler/testData/cfg/ArrayAccess.instructions

@@ -35,6 +35,7 @@ L0:
     call(a[10], get)
     r(1)
     call(+=, plus)
+    mark(a[10])
     r(a)
     r(10)
     r(1)

compiler/testData/cfg/arraySetPlusAssign.instructions

@@ -15,6 +15,7 @@ L0:
     call(a[0], get)
     r(1)
     call(+=, plus)
+    mark(a[0])
     r(a)
     r(0)
     r(1)