Fix GCM of CSE stores

Stop CSE of stores.
Backports to ch11,12,13,14

23 files changed, 104 insertions, 54 deletions

diff --git a/chapter11/src/main/java/com/seaofnodes/simple/GlobalCodeMotion.java b/chapter11/src/main/java/com/seaofnodes/simple/GlobalCodeMotion.java
index 054a489c..14540d46 100644
--- a/chapter11/src/main/java/com/seaofnodes/simple/GlobalCodeMotion.java
+++ b/chapter11/src/main/java/com/seaofnodes/simple/GlobalCodeMotion.java
@@ -120,7 +120,7 @@ public abstract class GlobalCodeMotion {
                 ns[i].setDef(0,late[i]);
     }
 
-    // Forwards post-order pass.  Schedule all outputs first, then draw a
+    // Forwards post-order pass.  Schedule all outputs first, then draw an
     // idom-tree line from the LCA of uses to the early schedule.  Schedule is
     // legal anywhere on this line; pick the most control-dependent (largest
     // idepth) in the shallowest loop nest.
@@ -154,7 +154,7 @@ public abstract class GlobalCodeMotion {
         if( n instanceof LoadNode load )
             lca = find_anti_dep(lca,load,early,late);
 
-        // Walk up from the LCA to the early, looking for best place.  This is
+        // Walk up from the LCA to the early, looking for best place.  This is the
         // lowest execution frequency, approximated by least loop depth and
         // deepest control flow.
         CFGNode best = lca;
diff --git a/chapter11/src/main/java/com/seaofnodes/simple/Parser.java b/chapter11/src/main/java/com/seaofnodes/simple/Parser.java
index e614d463..e367f499 100644
--- a/chapter11/src/main/java/com/seaofnodes/simple/Parser.java
+++ b/chapter11/src/main/java/com/seaofnodes/simple/Parser.java
@@ -601,7 +601,7 @@ public class Parser {
         Node n = new NewNode(TypeMemPtr.make(obj), ctrl()).peephole().keep();
         int alias = START._aliasStarts.get(obj._name);
         for( Field field : obj._fields ) {
-            memAlias(alias, new StoreNode(field._fname, alias, memAlias(alias), n, ZERO).peephole());
+            memAlias(alias, new StoreNode(field._fname, alias, ctrl(), memAlias(alias), n, ZERO).peephole());
             alias++;
         }
         return n.unkeep();
@@ -639,7 +639,7 @@ public class Parser {
             if( peek('=') ) _lexer._position--;
             else {
                 Node val = parseExpression();
-                memAlias(alias, new StoreNode(name, alias, memAlias(alias), expr, val).peephole());
+                memAlias(alias, new StoreNode(name, alias, ctrl(), memAlias(alias), expr, val).peephole());
                 return expr;        // "obj.a = expr" returns the expression while updating memory
             }
         }
diff --git a/chapter11/src/main/java/com/seaofnodes/simple/node/LoadNode.java b/chapter11/src/main/java/com/seaofnodes/simple/node/LoadNode.java
index 4ed06da4..296237f4 100644
--- a/chapter11/src/main/java/com/seaofnodes/simple/node/LoadNode.java
+++ b/chapter11/src/main/java/com/seaofnodes/simple/node/LoadNode.java
@@ -21,7 +21,7 @@ public class LoadNode extends MemOpNode {
      * @param memPtr The ptr to the struct from where we load a field
      */
     public LoadNode(String name, int alias, Type glb, Node memSlice, Node memPtr) {
-        super(name, alias, memSlice, memPtr);
+        super(name, alias, null, memSlice, memPtr);
         _declaredType = glb;
     }
 
diff --git a/chapter11/src/main/java/com/seaofnodes/simple/node/MemOpNode.java b/chapter11/src/main/java/com/seaofnodes/simple/node/MemOpNode.java
index 7f8d060a..551d2aa9 100644
--- a/chapter11/src/main/java/com/seaofnodes/simple/node/MemOpNode.java
+++ b/chapter11/src/main/java/com/seaofnodes/simple/node/MemOpNode.java
@@ -12,15 +12,11 @@ public abstract class MemOpNode extends Node {
     public final String _name;
     public final int _alias;
 
-    public MemOpNode(String name, int alias, Node memSlice, Node memPtr) {
-        super(null, memSlice, memPtr);
+    public MemOpNode(String name, int alias, Node... nodes) {
+        super(nodes);
         _name  = name;
         _alias = alias;
     }
-    public MemOpNode(String name, int alias, Node memSlice, Node memPtr, Node value) {
-        this(name, alias, memSlice, memPtr);
-        addDef(value);
-    }
 
     public Node mem() { return in(1); }
     public Node ptr() { return in(2); }
diff --git a/chapter11/src/main/java/com/seaofnodes/simple/node/StoreNode.java b/chapter11/src/main/java/com/seaofnodes/simple/node/StoreNode.java
index 7c41e767..db8e2ce6 100644
--- a/chapter11/src/main/java/com/seaofnodes/simple/node/StoreNode.java
+++ b/chapter11/src/main/java/com/seaofnodes/simple/node/StoreNode.java
@@ -17,8 +17,8 @@ public class StoreNode extends MemOpNode {
      * @param memPtr The ptr to the struct where we will store a value
      * @param value Value to be stored
      */
-    public StoreNode(String name, int alias, Node memSlice, Node memPtr, Node value) {
-        super(name, alias, memSlice, memPtr, value);
+    public StoreNode(String name, int alias, Node ctrl, Node memSlice, Node memPtr, Node value) {
+        super(name, alias, ctrl, memSlice, memPtr, value);
     }
 
     @Override
diff --git a/chapter11/src/test/java/com/seaofnodes/simple/Chapter11Test.java b/chapter11/src/test/java/com/seaofnodes/simple/Chapter11Test.java
index 9b05d66c..d1c0ac1d 100644
--- a/chapter11/src/test/java/com/seaofnodes/simple/Chapter11Test.java
+++ b/chapter11/src/test/java/com/seaofnodes/simple/Chapter11Test.java
@@ -496,7 +496,7 @@ return v;
     @Test
     public void testExample2() {
         Parser parser = new Parser(
-                """
+                                   """
 struct S { int f; }
 S v = new S;
 int i = arg;
@@ -507,8 +507,25 @@ while (arg > 0) {
     arg = arg - 1;
 }
 return v;
-                """);
+""");
         StopNode stop = parser.parse(false).iterate(true);
         //assertEquals("return new S;", stop.toString());
     }
+
+    @Test
+    public void testSplit() {
+        Parser parser = new Parser(
+                                   """
+struct S { int f; }
+S s = new S;
+if( arg==0 ) s.f = 1;
+else if (arg == 1) s.f = 1;
+return s.f;
+""");
+        StopNode stop = parser.parse(false).iterate(true);
+        assertEquals("return Phi(Region35,1,Phi(Region33,1,0));", stop.toString());
+        assertEquals(1L, Evaluator.evaluate(stop,  0));
+        assertEquals(1L, Evaluator.evaluate(stop,  1));
+        assertEquals(0L, Evaluator.evaluate(stop,  2));
+    }
 }
diff --git a/chapter12/src/main/java/com/seaofnodes/simple/Parser.java b/chapter12/src/main/java/com/seaofnodes/simple/Parser.java
index e919449f..1a223726 100644
--- a/chapter12/src/main/java/com/seaofnodes/simple/Parser.java
+++ b/chapter12/src/main/java/com/seaofnodes/simple/Parser.java
@@ -584,7 +584,7 @@ public class Parser {
         Node n = new NewNode(TypeMemPtr.make(obj), ctrl()).peephole().keep();
         int alias = START._aliasStarts.get(obj._name);
         for( Field field : obj._fields ) {
-            memAlias(alias, new StoreNode(field._fname, alias, memAlias(alias), n, ZERO).peephole());
+            memAlias(alias, new StoreNode(field._fname, alias, ctrl(), memAlias(alias), n, ZERO).peephole());
             alias++;
         }
         return n.unkeep();
@@ -623,7 +623,7 @@ public class Parser {
             if( peek('=') ) _lexer._position--;
             else {
                 Node val = parseExpression();
-                memAlias(alias, new StoreNode(name, alias, memAlias(alias), expr, val).peephole());
+                memAlias(alias, new StoreNode(name, alias, ctrl(), memAlias(alias), expr, val).peephole());
                 return expr;        // "obj.a = expr" returns the expression while updating memory
             }
         }
diff --git a/chapter12/src/main/java/com/seaofnodes/simple/node/LoadNode.java b/chapter12/src/main/java/com/seaofnodes/simple/node/LoadNode.java
index 95d49662..244a0919 100644
--- a/chapter12/src/main/java/com/seaofnodes/simple/node/LoadNode.java
+++ b/chapter12/src/main/java/com/seaofnodes/simple/node/LoadNode.java
@@ -21,7 +21,7 @@ public class LoadNode extends MemOpNode {
      * @param memPtr The ptr to the struct from where we load a field
      */
     public LoadNode(String name, int alias, Type glb, Node memSlice, Node memPtr) {
-        super(name, alias, memSlice, memPtr);
+        super(name, alias, null, memSlice, memPtr);
         _declaredType = glb;
     }
 
diff --git a/chapter12/src/main/java/com/seaofnodes/simple/node/MemOpNode.java b/chapter12/src/main/java/com/seaofnodes/simple/node/MemOpNode.java
index 7f8d060a..551d2aa9 100644
--- a/chapter12/src/main/java/com/seaofnodes/simple/node/MemOpNode.java
+++ b/chapter12/src/main/java/com/seaofnodes/simple/node/MemOpNode.java
@@ -12,15 +12,11 @@ public abstract class MemOpNode extends Node {
     public final String _name;
     public final int _alias;
 
-    public MemOpNode(String name, int alias, Node memSlice, Node memPtr) {
-        super(null, memSlice, memPtr);
+    public MemOpNode(String name, int alias, Node... nodes) {
+        super(nodes);
         _name  = name;
         _alias = alias;
     }
-    public MemOpNode(String name, int alias, Node memSlice, Node memPtr, Node value) {
-        this(name, alias, memSlice, memPtr);
-        addDef(value);
-    }
 
     public Node mem() { return in(1); }
     public Node ptr() { return in(2); }
diff --git a/chapter12/src/main/java/com/seaofnodes/simple/node/StoreNode.java b/chapter12/src/main/java/com/seaofnodes/simple/node/StoreNode.java
index 7c41e767..db8e2ce6 100644
--- a/chapter12/src/main/java/com/seaofnodes/simple/node/StoreNode.java
+++ b/chapter12/src/main/java/com/seaofnodes/simple/node/StoreNode.java
@@ -17,8 +17,8 @@ public class StoreNode extends MemOpNode {
      * @param memPtr The ptr to the struct where we will store a value
      * @param value Value to be stored
      */
-    public StoreNode(String name, int alias, Node memSlice, Node memPtr, Node value) {
-        super(name, alias, memSlice, memPtr, value);
+    public StoreNode(String name, int alias, Node ctrl, Node memSlice, Node memPtr, Node value) {
+        super(name, alias, ctrl, memSlice, memPtr, value);
     }
 
     @Override
diff --git a/chapter12/src/test/java/com/seaofnodes/simple/Chapter11Test.java b/chapter12/src/test/java/com/seaofnodes/simple/Chapter11Test.java
index 6c1f7938..dfb1786b 100644
--- a/chapter12/src/test/java/com/seaofnodes/simple/Chapter11Test.java
+++ b/chapter12/src/test/java/com/seaofnodes/simple/Chapter11Test.java
@@ -511,4 +511,21 @@ return v;
         StopNode stop = parser.parse(false).iterate(true);
         //assertEquals("return new S;", stop.toString());
     }
+
+    @Test
+    public void testSplit() {
+        Parser parser = new Parser(
+                                   """
+struct S { int f; }
+S s = new S;
+if( arg==0 ) s.f = 1;
+else if (arg == 1) s.f = 1;
+return s.f;
+""");
+        StopNode stop = parser.parse(false).iterate(true);
+        assertEquals("return Phi(Region35,1,Phi(Region33,1,0));", stop.toString());
+        assertEquals(1L, Evaluator.evaluate(stop,  0));
+        assertEquals(1L, Evaluator.evaluate(stop,  1));
+        assertEquals(0L, Evaluator.evaluate(stop,  2));
+    }
 }
diff --git a/chapter13/src/main/java/com/seaofnodes/simple/Parser.java b/chapter13/src/main/java/com/seaofnodes/simple/Parser.java
index f04bf5c3..53448e4d 100644
--- a/chapter13/src/main/java/com/seaofnodes/simple/Parser.java
+++ b/chapter13/src/main/java/com/seaofnodes/simple/Parser.java
@@ -598,7 +598,7 @@ public class Parser {
         Node n = new NewNode(TypeMemPtr.make(obj), ctrl()).peephole().keep();
         int alias = START._aliasStarts.get(obj._name);
         for( Field field : obj._fields ) {
-            memAlias(alias, new StoreNode(field._fname, alias, field._type, memAlias(alias), n, new ConstantNode(field._type.makeInit()).peephole(),true).peephole());
+            memAlias(alias, new StoreNode(field._fname, alias, field._type, ctrl(), memAlias(alias), n, new ConstantNode(field._type.makeInit()).peephole(),true).peephole());
             alias++;
         }
         return n.unkeep();
@@ -640,7 +640,7 @@ public class Parser {
             else {
                 Node val = parseExpression();
                 Type glb = base._fields[idx]._type;
-                memAlias(alias, new StoreNode(name, alias,glb, memAlias(alias), expr, val, false).peephole());
+                memAlias(alias, new StoreNode(name, alias,glb, ctrl(), memAlias(alias), expr, val, false).peephole());
                 return expr;        // "obj.a = expr" returns the expression while updating memory
             }
         }
diff --git a/chapter13/src/main/java/com/seaofnodes/simple/node/LoadNode.java b/chapter13/src/main/java/com/seaofnodes/simple/node/LoadNode.java
index 4e1421fa..a033a7cf 100644
--- a/chapter13/src/main/java/com/seaofnodes/simple/node/LoadNode.java
+++ b/chapter13/src/main/java/com/seaofnodes/simple/node/LoadNode.java
@@ -19,7 +19,7 @@ public class LoadNode extends MemOpNode {
      * @param memPtr The ptr to the struct from where we load a field
      */
     public LoadNode(String name, int alias, Type glb, Node memSlice, Node memPtr) {
-        super(name, alias, glb, memSlice, memPtr);
+        super(name, alias, glb, null, memSlice, memPtr);
     }
 
     @Override public String  label() { return     _name; }
diff --git a/chapter13/src/main/java/com/seaofnodes/simple/node/MemOpNode.java b/chapter13/src/main/java/com/seaofnodes/simple/node/MemOpNode.java
index bc8e46d3..95319c24 100644
--- a/chapter13/src/main/java/com/seaofnodes/simple/node/MemOpNode.java
+++ b/chapter13/src/main/java/com/seaofnodes/simple/node/MemOpNode.java
@@ -14,16 +14,11 @@ public abstract class MemOpNode extends Node {
     public final Type _declaredType;
 
 
-    public MemOpNode(String name, int alias, Type glb, Node memSlice, Node memPtr) {
-        super(null, memSlice, memPtr);
+    public MemOpNode(String name, int alias, Type glb, Node... nodes ) {
+        super(nodes);
         _name  = name;
         _alias = alias;
         _declaredType = glb;
-
-    }
-    public MemOpNode(String name, int alias, Type glb, Node memSlice, Node memPtr, Node value) {
-        this(name, alias, glb, memSlice, memPtr);
-        addDef(value);
     }
 
     public Node mem() { return in(1); }
diff --git a/chapter13/src/main/java/com/seaofnodes/simple/node/StoreNode.java b/chapter13/src/main/java/com/seaofnodes/simple/node/StoreNode.java
index 44a14be1..57e8b3ad 100644
--- a/chapter13/src/main/java/com/seaofnodes/simple/node/StoreNode.java
+++ b/chapter13/src/main/java/com/seaofnodes/simple/node/StoreNode.java
@@ -19,12 +19,12 @@ public class StoreNode extends MemOpNode {
      * @param memPtr The ptr to the struct where we will store a value
      * @param value Value to be stored
      */
-    public StoreNode(String name, int alias, Type glb, Node memSlice, Node memPtr, Node value, boolean init) {
-        super(name, alias, glb, memSlice, memPtr, value);
+    public StoreNode(String name, int alias, Type glb, Node ctrl, Node memSlice, Node memPtr, Node value, boolean init) {
+        super(name, alias, glb, ctrl, memSlice, memPtr, value);
         _init = init;
     }
 
-    @Override public String  label() { return "ST"+_name; }
+    @Override public String  label() { return "." +_name+"="; }
     @Override public String glabel() { return "." +_name+"="; }
     @Override public boolean isMem() { return true; }
 
diff --git a/chapter13/src/test/java/com/seaofnodes/simple/Chapter11Test.java b/chapter13/src/test/java/com/seaofnodes/simple/Chapter11Test.java
index e367184c..a47bf471 100644
--- a/chapter13/src/test/java/com/seaofnodes/simple/Chapter11Test.java
+++ b/chapter13/src/test/java/com/seaofnodes/simple/Chapter11Test.java
@@ -511,4 +511,21 @@ return v;
         StopNode stop = parser.parse(false).iterate(true);
         //assertEquals("return new S;", stop.toString());
     }
+
+    @Test
+    public void testSplit() {
+        Parser parser = new Parser(
+                                   """
+struct S { int f; }
+S s = new S;
+if( arg==0 ) s.f = 1;
+else if (arg == 1) s.f = 1;
+return s.f;
+""");
+        StopNode stop = parser.parse(false).iterate(true);
+        assertEquals("return Phi(Region37,1,Phi(Region35,1,0));", stop.toString());
+        assertEquals(1L, Evaluator.evaluate(stop,  0));
+        assertEquals(1L, Evaluator.evaluate(stop,  1));
+        assertEquals(0L, Evaluator.evaluate(stop,  2));
+    }
 }
diff --git a/chapter13/src/test/java/com/seaofnodes/simple/Chapter13Test.java b/chapter13/src/test/java/com/seaofnodes/simple/Chapter13Test.java
index f7d4d5a8..a58ad583 100644
--- a/chapter13/src/test/java/com/seaofnodes/simple/Chapter13Test.java
+++ b/chapter13/src/test/java/com/seaofnodes/simple/Chapter13Test.java
@@ -35,7 +35,7 @@ while( arg ) {
 return head.next.i;
 """);
         try { parser.parse(true).iterate(true); fail(); }
-        catch( Exception e ) { assertEquals("Might be null accessing 'i'",e.getMessage()); }
+        catch( Exception e ) { assertEquals("Might be null accessing 'next'",e.getMessage()); }
     }
 
     @Test
diff --git a/chapter14/src/main/java/com/seaofnodes/simple/Parser.java b/chapter14/src/main/java/com/seaofnodes/simple/Parser.java
index bea06a19..417f4295 100644
--- a/chapter14/src/main/java/com/seaofnodes/simple/Parser.java
+++ b/chapter14/src/main/java/com/seaofnodes/simple/Parser.java
@@ -668,7 +668,7 @@ public class Parser {
         Node n = new NewNode(TypeMemPtr.make(obj), ctrl()).peephole().keep();
         int alias = START._aliasStarts.get(obj._name);
         for( Field field : obj._fields ) {
-            memAlias(alias, new StoreNode(field._fname, alias, field._type, memAlias(alias), n, new ConstantNode(field._type.makeInit()).peephole(),true).peephole());
+            memAlias(alias, new StoreNode(field._fname, alias, field._type, ctrl(), memAlias(alias), n, new ConstantNode(field._type.makeInit()).peephole(),true).peephole());
             alias++;
         }
         return n.unkeep();
@@ -712,7 +712,7 @@ public class Parser {
                 Type glb = base._fields[idx]._type;
                 // Auto-truncate when storing to narrow fields
                 val = zsMask(val,glb);
-                memAlias(alias, new StoreNode(name, alias,glb, memAlias(alias), expr, val, false).peephole());
+                memAlias(alias, new StoreNode(name, alias,glb, ctrl(), memAlias(alias), expr, val, false).peephole());
                 return expr;        // "obj.a = expr" returns the expression while updating memory
             }
         }
diff --git a/chapter14/src/main/java/com/seaofnodes/simple/node/LoadNode.java b/chapter14/src/main/java/com/seaofnodes/simple/node/LoadNode.java
index 4e1421fa..a033a7cf 100644
--- a/chapter14/src/main/java/com/seaofnodes/simple/node/LoadNode.java
+++ b/chapter14/src/main/java/com/seaofnodes/simple/node/LoadNode.java
@@ -19,7 +19,7 @@ public class LoadNode extends MemOpNode {
      * @param memPtr The ptr to the struct from where we load a field
      */
     public LoadNode(String name, int alias, Type glb, Node memSlice, Node memPtr) {
-        super(name, alias, glb, memSlice, memPtr);
+        super(name, alias, glb, null, memSlice, memPtr);
     }
 
     @Override public String  label() { return     _name; }
diff --git a/chapter14/src/main/java/com/seaofnodes/simple/node/MemOpNode.java b/chapter14/src/main/java/com/seaofnodes/simple/node/MemOpNode.java
index bc8e46d3..76564db0 100644
--- a/chapter14/src/main/java/com/seaofnodes/simple/node/MemOpNode.java
+++ b/chapter14/src/main/java/com/seaofnodes/simple/node/MemOpNode.java
@@ -14,16 +14,11 @@ public abstract class MemOpNode extends Node {
     public final Type _declaredType;
 
 
-    public MemOpNode(String name, int alias, Type glb, Node memSlice, Node memPtr) {
-        super(null, memSlice, memPtr);
+    public MemOpNode(String name, int alias, Type glb, Node...  nodes) {
+        super(nodes);
         _name  = name;
         _alias = alias;
         _declaredType = glb;
-
-    }
-    public MemOpNode(String name, int alias, Type glb, Node memSlice, Node memPtr, Node value) {
-        this(name, alias, glb, memSlice, memPtr);
-        addDef(value);
     }
 
     public Node mem() { return in(1); }
diff --git a/chapter14/src/main/java/com/seaofnodes/simple/node/StoreNode.java b/chapter14/src/main/java/com/seaofnodes/simple/node/StoreNode.java
index 44a14be1..57e8b3ad 100644
--- a/chapter14/src/main/java/com/seaofnodes/simple/node/StoreNode.java
+++ b/chapter14/src/main/java/com/seaofnodes/simple/node/StoreNode.java
@@ -19,12 +19,12 @@ public class StoreNode extends MemOpNode {
      * @param memPtr The ptr to the struct where we will store a value
      * @param value Value to be stored
      */
-    public StoreNode(String name, int alias, Type glb, Node memSlice, Node memPtr, Node value, boolean init) {
-        super(name, alias, glb, memSlice, memPtr, value);
+    public StoreNode(String name, int alias, Type glb, Node ctrl, Node memSlice, Node memPtr, Node value, boolean init) {
+        super(name, alias, glb, ctrl, memSlice, memPtr, value);
         _init = init;
     }
 
-    @Override public String  label() { return "ST"+_name; }
+    @Override public String  label() { return "." +_name+"="; }
     @Override public String glabel() { return "." +_name+"="; }
     @Override public boolean isMem() { return true; }
 
diff --git a/chapter14/src/test/java/com/seaofnodes/simple/Chapter11Test.java b/chapter14/src/test/java/com/seaofnodes/simple/Chapter11Test.java
index 3b9cac7d..ca0db829 100644
--- a/chapter14/src/test/java/com/seaofnodes/simple/Chapter11Test.java
+++ b/chapter14/src/test/java/com/seaofnodes/simple/Chapter11Test.java
@@ -511,4 +511,21 @@ return v;
         StopNode stop = parser.parse(false).iterate(true);
         //assertEquals("return new S;", stop.toString());
     }
+
+    @Test
+    public void testSplit() {
+        Parser parser = new Parser(
+                                   """
+struct S { int f; }
+S s = new S;
+if( arg==0 ) s.f = 1;
+else if (arg == 1) s.f = 1;
+return s.f;
+""");
+        StopNode stop = parser.parse(false).iterate(true);
+        assertEquals("return Phi(Region37,1,Phi(Region35,1,0));", stop.toString());
+        assertEquals(1L, Evaluator.evaluate(stop,  0));
+        assertEquals(1L, Evaluator.evaluate(stop,  1));
+        assertEquals(0L, Evaluator.evaluate(stop,  2));
+    }
 }
diff --git a/chapter14/src/test/java/com/seaofnodes/simple/Chapter13Test.java b/chapter14/src/test/java/com/seaofnodes/simple/Chapter13Test.java
index f9aa3016..11ab5621 100644
--- a/chapter14/src/test/java/com/seaofnodes/simple/Chapter13Test.java
+++ b/chapter14/src/test/java/com/seaofnodes/simple/Chapter13Test.java
@@ -35,7 +35,7 @@ while( arg ) {
 return head.next.i;
 """);
         try { parser.parse(true).iterate(true); fail(); }
-        catch( Exception e ) { assertEquals("Might be null accessing 'i'",e.getMessage()); }
+        catch( Exception e ) { assertEquals("Might be null accessing 'next'",e.getMessage()); }
     }
 
     @Test