Clean up del code

3 files changed, 7 insertions, 13 deletions

diff --git a/chapter15/src/main/java/com/seaofnodes/simple/IRPrinter.java b/chapter15/src/main/java/com/seaofnodes/simple/IRPrinter.java
index aa84b25b..418cda29 100644
--- a/chapter15/src/main/java/com/seaofnodes/simple/IRPrinter.java
+++ b/chapter15/src/main/java/com/seaofnodes/simple/IRPrinter.java
@@ -176,8 +176,8 @@ public class IRPrinter {
             _bs.set(n._nid);
         }
         void del(int idx) {
-            Node n = Utils.del(_bfs, idx);
-            _bs.clear(n._nid);
+            _bs.clear(_bfs.get(idx)._nid);
+            Utils.del(_bfs, idx);
         }
         boolean any_visited( Node n ) {
             for( Node def : n._inputs )
diff --git a/chapter15/src/main/java/com/seaofnodes/simple/Utils.java b/chapter15/src/main/java/com/seaofnodes/simple/Utils.java
index f3ac25b1..1346c3ea 100644
--- a/chapter15/src/main/java/com/seaofnodes/simple/Utils.java
+++ b/chapter15/src/main/java/com/seaofnodes/simple/Utils.java
@@ -13,14 +13,9 @@ public class Utils {
      *  @param i element to be removed
      *  @return element removed
      */
-    public static <E> E del(ArrayList<E> array, int i) {
-        if ( i >= 0 && i < array.size() ) {
-            E tmp = array.get(i);
-            E last = array.removeLast();
-            if (i < array.size()) array.set(i, last);
-            return tmp;
-        }
-        return null;
+    public static <E> void del(ArrayList<E> array, int i) {
+        E last = array.removeLast();
+        if (i < array.size()) array.set(i, last);
     }
 
     /**
diff --git a/chapter15/src/main/java/com/seaofnodes/simple/node/Node.java b/chapter15/src/main/java/com/seaofnodes/simple/node/Node.java
index c3a0f20f..e4b887a0 100644
--- a/chapter15/src/main/java/com/seaofnodes/simple/node/Node.java
+++ b/chapter15/src/main/java/com/seaofnodes/simple/node/Node.java
@@ -179,11 +179,10 @@ public abstract class Node implements OutNode {
     Node delDef(int idx) {
         unlock();
         Node old_def = in(idx);
-        if( old_def != null &&  // If the old def exists, remove a def->use edge
-            old_def.delUse(this) ) // If we removed the last use, the old def is now dead
+        Utils.del(_inputs, idx);
+        if( old_def.delUse(this) ) // If we removed the last use, the old def is now dead
             old_def.kill();     // Kill old def
         old_def.moveDepsToWorklist();
-        Utils.del(_inputs, idx);
         return this;
     }