Bring forward the lazy mem alias

Integrate with ch15 NewNode creating aliases

15 files changed, 327 insertions, 81 deletions

diff --git a/chapter15/src/test/java/com/seaofnodes/simple/Chapter04Test.java b/chapter15/src/test/java/com/seaofnodes/simple/Chapter04Test.java
index a3109ff7..14d31245 100644
--- a/chapter15/src/test/java/com/seaofnodes/simple/Chapter04Test.java
+++ b/chapter15/src/test/java/com/seaofnodes/simple/Chapter04Test.java
@@ -84,7 +84,10 @@ public class Chapter04Test {
         StopNode stop = parser.parse();
         ReturnNode ret = stop.ret();
         assertTrue(ret.in(0) instanceof CProjNode);
-        assertTrue(ret.in(1) instanceof  ProjNode);
+        assertTrue(ret.in(1) instanceof ProjNode);
+        assertEquals(1, ((ProjNode)ret.in(1))._idx);
+        assertTrue(ret.in(2) instanceof ProjNode);
+        assertEquals(2, ((ProjNode)ret.in(2))._idx);
     }
 
     @Test
diff --git a/chapter15/src/test/java/com/seaofnodes/simple/Chapter05Test.java b/chapter15/src/test/java/com/seaofnodes/simple/Chapter05Test.java
index 9d154413..ca7bb482 100644
--- a/chapter15/src/test/java/com/seaofnodes/simple/Chapter05Test.java
+++ b/chapter15/src/test/java/com/seaofnodes/simple/Chapter05Test.java
@@ -22,7 +22,7 @@ else {
 
 return a;""");
         StopNode ret = parser.parse().iterate();
-        assertEquals("return Phi(Region20,(arg+2),(arg-3));", ret.toString());
+        assertEquals("return Phi(Region21,(arg+2),(arg-3));", ret.toString());
     }
 
     @Test
@@ -37,7 +37,7 @@ if (arg == 1) {
 }
 return c;""", TypeInteger.BOT);
         StopNode ret = parser.parse().iterate();
-        assertEquals("return Phi(Region19,4,3);", ret.toString());
+        assertEquals("return Phi(Region20,4,3);", ret.toString());
     }
 
     @Test
@@ -65,7 +65,7 @@ else
     b=a+1;
 return a+b;""");
         StopNode ret = parser.parse().iterate();
-        assertEquals("return ((arg*2)+Phi(Region23,2,3));", ret.toString());
+        assertEquals("return ((arg*2)+Phi(Region24,2,3));", ret.toString());
     }
 
     @Test
@@ -80,7 +80,7 @@ else
     a=b+1;
 return a+b;""");
         StopNode ret = parser.parse().iterate();
-        assertEquals("return ((Phi(Region34,(arg*2),arg)+arg)+Phi(Region,4,5));", ret.toString());
+        assertEquals("return ((Phi(Region35,(arg*2),arg)+arg)+Phi(Region,4,5));", ret.toString());
     }
 
     @Test
@@ -100,7 +100,7 @@ else
 return a;
 """, TypeInteger.BOT);
         StopNode stop = parser.parse().iterate();
-        assertEquals("return Phi(Region38,Phi(Region24,2,3),Phi(Region36,4,5));", stop.toString());
+        assertEquals("return Phi(Region39,Phi(Region25,2,3),Phi(Region37,4,5));", stop.toString());
     }
 
     @Test
@@ -116,7 +116,7 @@ if( arg==0 )
 return arg+a+b;
 """, TypeInteger.BOT);
         StopNode stop = parser.parse();
-        assertEquals("return ((arg+Phi(Region17,1,0))+Phi(Region33,2,0));", stop.toString());
+        assertEquals("return ((arg+Phi(Region18,1,0))+Phi(Region34,2,0));", stop.toString());
     }
 
     @Test
@@ -130,7 +130,7 @@ if( arg==1 )
 }
 return a;""");
         StopNode ret = parser.parse().iterate();
-        assertEquals("return (arg==Phi(Region19,3,2));", ret.toString());
+        assertEquals("return (arg==Phi(Region20,3,2));", ret.toString());
     }
 
     @Test
diff --git a/chapter15/src/test/java/com/seaofnodes/simple/Chapter06Test.java b/chapter15/src/test/java/com/seaofnodes/simple/Chapter06Test.java
index ae37a867..d2c46df5 100644
--- a/chapter15/src/test/java/com/seaofnodes/simple/Chapter06Test.java
+++ b/chapter15/src/test/java/com/seaofnodes/simple/Chapter06Test.java
@@ -65,7 +65,7 @@ else
     b=5;
 return b;""", TypeInteger.BOT);
         StopNode stop = parser.parse().iterate();
-        assertEquals("return Phi(Region39,42,5);", stop.toString());
+        assertEquals("return Phi(Region40,42,5);", stop.toString());
     }
 
     @Test
@@ -84,7 +84,7 @@ else
     b=5;
 return b;""", TypeInteger.BOT);
         StopNode stop = parser.parse().iterate();
-        assertEquals("return Phi(Region32,2,5);", stop.toString());
+        assertEquals("return Phi(Region33,2,5);", stop.toString());
     }
 
     @Test
@@ -144,7 +144,7 @@ else
 return a;
 """, TypeInteger.BOT);
         StopNode stop = parser.parse().iterate();
-        assertEquals("return Phi(Region43,3,Phi(Region41,4,5));", stop.toString());
+        assertEquals("return Phi(Region44,3,Phi(Region42,4,5));", stop.toString());
     }
 
     @Test
@@ -200,7 +200,7 @@ if( arg ) {
 return a+b;
 """);
         StopNode ret = parser.parse().iterate();
-        assertEquals("return Phi(Region28,4,1);", ret.toString());
+        assertEquals("return Phi(Region29,4,1);", ret.toString());
     }
 
 
@@ -251,7 +251,7 @@ if( arg ) {
 return a+b+c;
 """);
         StopNode ret = parser.parse().iterate();
-        assertEquals("return (Phi(Region40,Phi(Region25,2,3),0)+Phi(Region,3,1));", ret.toString());
+        assertEquals("return (Phi(Region41,Phi(Region26,2,3),0)+Phi(Region,3,1));", ret.toString());
     }
 
 
diff --git a/chapter15/src/test/java/com/seaofnodes/simple/Chapter07Test.java b/chapter15/src/test/java/com/seaofnodes/simple/Chapter07Test.java
index 29aa7eaf..443b0d17 100644
--- a/chapter15/src/test/java/com/seaofnodes/simple/Chapter07Test.java
+++ b/chapter15/src/test/java/com/seaofnodes/simple/Chapter07Test.java
@@ -17,7 +17,7 @@ public class Chapter07Test {
                 return arg;
                 """);
         StopNode stop = parser.parse();
-        assertEquals("return Phi(Loop8,arg,(Phi_arg+1));", stop.toString());
+        assertEquals("return Phi(Loop9,arg,(Phi_arg+1));", stop.toString());
         assertTrue(stop.ret().ctrl() instanceof CProjNode);
     }
 
@@ -34,7 +34,7 @@ if(arg){}else{
 return a;
 """);
         StopNode stop = parser.parse().iterate();
-        assertEquals("return Phi(Region26,1,Phi(Loop15,1,(Phi_a+1)));", stop.toString());
+        assertEquals("return Phi(Region27,1,Phi(Loop16,1,(Phi_a+1)));", stop.toString());
     }
 
     @Test
@@ -54,7 +54,7 @@ while(i < arg) {
 return sum;
 """);
         StopNode stop = parser.parse().iterate();
-        assertEquals("return Phi(Loop10,0,Phi(Loop22,Phi_sum,(Phi_sum+Phi(Loop,0,(Phi_j+1)))));", stop.toString());
+        assertEquals("return Phi(Loop11,0,Phi(Loop23,Phi_sum,(Phi_sum+Phi(Loop,0,(Phi_j+1)))));", stop.toString());
     }
 
     @Test
@@ -70,7 +70,7 @@ while(a < 10) {
 return b;
 """);
         StopNode stop = parser.parse();
-        assertEquals("return Phi(Loop10,2,Phi(Region29,Phi_b,4));", stop.toString());
+        assertEquals("return Phi(Loop11,2,Phi(Region30,Phi_b,4));", stop.toString());
         assertTrue(stop.ret().ctrl() instanceof CProjNode);
     }
 
@@ -89,7 +89,7 @@ while(a < 10) {
 return b;
 """);
         StopNode stop = parser.parse().iterate();
-        assertEquals("return Phi(Loop10,2,(Phi(Region29,Phi_b,4)+1));", stop.toString());
+        assertEquals("return Phi(Loop11,2,(Phi(Region30,Phi_b,4)+1));", stop.toString());
         assertTrue(stop.ret().ctrl() instanceof CProjNode);
     }
 
@@ -106,7 +106,7 @@ while(a < 10) {
 return a;
 """);
         StopNode stop = parser.parse();
-        assertEquals("return Phi(Loop9,1,(Phi_a+3));", stop.toString());
+        assertEquals("return Phi(Loop10,1,(Phi_a+3));", stop.toString());
         assertTrue(stop.ret().ctrl() instanceof CProjNode);
     }
 
@@ -122,7 +122,7 @@ while(a < 10) {
 return a;
 """);
         StopNode stop = parser.parse().iterate();
-        assertEquals("return Phi(Loop9,1,(Phi_a+3));", stop.toString());
+        assertEquals("return Phi(Loop10,1,(Phi_a+3));", stop.toString());
         assertTrue(stop.ret().ctrl() instanceof CProjNode);
     }
 
@@ -135,7 +135,7 @@ while(arg) a = 2;
 return a;
 """);
         StopNode stop = parser.parse();
-        assertEquals("return Phi(Loop9,1,2);", stop.toString());
+        assertEquals("return Phi(Loop10,1,2);", stop.toString());
         assertTrue(stop.ret().ctrl() instanceof CProjNode);
     }
 
@@ -148,7 +148,7 @@ while(arg) a = 2;
 return a;
 """);
         StopNode stop = parser.parse().iterate();
-        assertEquals("return Phi(Loop9,1,2);", stop.toString());
+        assertEquals("return Phi(Loop10,1,2);", stop.toString());
         assertTrue(stop.ret().ctrl() instanceof CProjNode);
     }
 
@@ -164,7 +164,7 @@ while(a < 10) {
 return a;
 """);
         StopNode stop = parser.parse();
-        assertEquals("return Phi(Loop9,1,(Phi_a+3));", stop.toString());
+        assertEquals("return Phi(Loop10,1,(Phi_a+3));", stop.toString());
         assertTrue(stop.ret().ctrl() instanceof CProjNode);
     }
 
@@ -180,7 +180,7 @@ while(a < 10) {
 return a;
 """);
         StopNode stop = parser.parse().iterate();
-        assertEquals("return Phi(Loop9,1,(Phi_a+3));", stop.toString());
+        assertEquals("return Phi(Loop10,1,(Phi_a+3));", stop.toString());
         assertTrue(stop.ret().ctrl() instanceof CProjNode);
     }
 
@@ -197,7 +197,7 @@ while(a < 10) {
 return a;
 """);
         StopNode stop = parser.parse();
-        assertEquals("return Phi(Loop10,1,(Phi_a+3));", stop.toString());
+        assertEquals("return Phi(Loop11,1,(Phi_a+3));", stop.toString());
         assertTrue(stop.ret().ctrl() instanceof CProjNode);
     }
 
@@ -214,7 +214,7 @@ while(a < 10) {
 return a;
 """);
         StopNode stop = parser.parse().iterate();
-        assertEquals("return Phi(Loop10,1,(Phi_a+3));", stop.toString());
+        assertEquals("return Phi(Loop11,1,(Phi_a+3));", stop.toString());
         assertTrue(stop.ret().ctrl() instanceof CProjNode);
     }
 
diff --git a/chapter15/src/test/java/com/seaofnodes/simple/Chapter08Test.java b/chapter15/src/test/java/com/seaofnodes/simple/Chapter08Test.java
index 7760ae09..89ce8313 100644
--- a/chapter15/src/test/java/com/seaofnodes/simple/Chapter08Test.java
+++ b/chapter15/src/test/java/com/seaofnodes/simple/Chapter08Test.java
@@ -23,7 +23,7 @@ while(arg < 10) {
 return arg;
                 """);
         StopNode stop = parser.parse().iterate();
-        assertEquals("return Phi(Region37,Phi(Region26,Phi(Loop8,arg,(Phi_arg+1)),Add),Add);", stop.toString());
+        assertEquals("return Phi(Region38,Phi(Region27,Phi(Loop9,arg,(Phi_arg+1)),Add),Add);", stop.toString());
         assertTrue(stop.ret().ctrl() instanceof RegionNode);
         Assert.assertEquals(5L, Evaluator.evaluate(stop, 1));
         Assert.assertEquals(10L, Evaluator.evaluate(stop, 6));
@@ -46,7 +46,7 @@ while(arg < 10) {
 return a;
                 """);
         StopNode stop = parser.parse().iterate();
-        assertEquals("return Phi(Loop9,1,Phi(Region43,Phi_a,(Phi_a+1)));", stop.toString());
+        assertEquals("return Phi(Loop10,1,Phi(Region44,Phi_a,(Phi_a+1)));", stop.toString());
         assertTrue(stop.ret().ctrl() instanceof CProjNode);
     }
 
@@ -65,7 +65,7 @@ while(arg < 10) {
 return arg;
                 """);
         StopNode stop = parser.parse().iterate();
-        assertEquals("return Phi(Region35,Phi(Loop8,arg,(Phi_arg+1)),Add);", stop.toString());
+        assertEquals("return Phi(Region36,Phi(Loop9,arg,(Phi_arg+1)),Add);", stop.toString());
         assertTrue(stop.ret().ctrl() instanceof RegionNode);
     }
 
@@ -81,7 +81,7 @@ while(arg < 10) {
 return arg;
                 """);
         StopNode stop = parser.parse().iterate();
-        assertEquals("return Phi(Region26,Phi(Loop8,arg,(Phi_arg+1)),Add);", stop.toString());
+        assertEquals("return Phi(Region27,Phi(Loop9,arg,(Phi_arg+1)),Add);", stop.toString());
         assertTrue(stop.ret().ctrl() instanceof RegionNode);
     }
 
@@ -100,7 +100,7 @@ while(arg < 10) {
 return arg;
                 """);
         StopNode stop = parser.parse().iterate();
-        assertEquals("return Phi(Loop8,arg,(Phi_arg+1));", stop.toString());
+        assertEquals("return Phi(Loop9,arg,(Phi_arg+1));", stop.toString());
         assertTrue(stop.ret().ctrl() instanceof CProjNode);
     }
 
@@ -117,7 +117,7 @@ while(arg < 10) {
 return arg;
                 """);
         StopNode stop = parser.parse().iterate();
-        assertEquals("return Phi(Loop8,arg,(Phi_arg+1));", stop.toString());
+        assertEquals("return Phi(Loop9,arg,(Phi_arg+1));", stop.toString());
         assertTrue(stop.ret().ctrl() instanceof CProjNode);
     }
 
@@ -185,7 +185,7 @@ while(arg < 10) {
 return a;
 """);
         StopNode stop = parser.parse().iterate();
-        assertEquals("return Phi(Region29,Phi(Loop9,1,(Phi_a+1)),Add);", stop.toString());
+        assertEquals("return Phi(Region30,Phi(Loop10,1,(Phi_a+1)),Add);", stop.toString());
         assertTrue(stop.ret().ctrl() instanceof RegionNode);
     }
 
@@ -201,7 +201,7 @@ while(1) {
 return a;
 """);
         StopNode stop = parser.parse().iterate();
-        assertEquals("return (Phi(Loop9,1,Add)+1);", stop.toString());
+        assertEquals("return (Phi(Loop10,1,Add)+1);", stop.toString());
         assertTrue(stop.ret().ctrl() instanceof CProjNode prj && prj._idx==1 );
     }
 
diff --git a/chapter15/src/test/java/com/seaofnodes/simple/Chapter09Test.java b/chapter15/src/test/java/com/seaofnodes/simple/Chapter09Test.java
index 64bbf245..49ee75a2 100644
--- a/chapter15/src/test/java/com/seaofnodes/simple/Chapter09Test.java
+++ b/chapter15/src/test/java/com/seaofnodes/simple/Chapter09Test.java
@@ -69,7 +69,7 @@ while (arg < 10) {
 return arg;
                 """);
         StopNode stop = parser.parse().iterate();
-        assertEquals("return Phi(Loop9,arg,(Phi_arg+2));", stop.toString());
+        assertEquals("return Phi(Loop10,arg,(Phi_arg+2));", stop.toString());
         Assert.assertEquals(11L, Evaluator.evaluate(stop, 1));
     }
 
@@ -86,7 +86,7 @@ while (arg < 10) {
 return arg;
                 """);
         StopNode stop = parser.parse().iterate();
-        assertEquals("return Phi(Loop10,arg,(Phi_arg+4));", stop.toString());
+        assertEquals("return Phi(Loop11,arg,(Phi_arg+4));", stop.toString());
         Assert.assertEquals(13L, Evaluator.evaluate(stop, 1));
     }
 
@@ -115,7 +115,7 @@ while (arg) {
 return arg;
                 """);
         StopNode stop = parser.parse().iterate();
-        assertEquals("return Phi(Loop16,arg,(Phi_arg+1));", stop.toString());
+        assertEquals("return Phi(Loop17,arg,(Phi_arg+1));", stop.toString());
     }
 
     @Test
@@ -185,7 +185,7 @@ while(arg) {
 return a;
 """);
         StopNode stop = parser.parse().iterate();
-        assertEquals("return Phi(Loop11,0,(-(Phi_a+3)));", stop.toString());
+        assertEquals("return Phi(Loop12,0,(-(Phi_a+3)));", stop.toString());
     }
 
     @Test
@@ -283,7 +283,7 @@ return v1+v0;
     public void testFuzz8() {
         Parser parser = new Parser("while(arg) arg = arg - 1;  return arg;");
         StopNode stop = parser.parse().iterate();
-        assertEquals("return Phi(Loop8,arg,(Phi_arg-1));", stop.toString());
+        assertEquals("return Phi(Loop9,arg,(Phi_arg-1));", stop.toString());
     }
 
     @Test
diff --git a/chapter15/src/test/java/com/seaofnodes/simple/Chapter10Test.java b/chapter15/src/test/java/com/seaofnodes/simple/Chapter10Test.java
index bd56a944..a5e3a9e0 100644
--- a/chapter15/src/test/java/com/seaofnodes/simple/Chapter10Test.java
+++ b/chapter15/src/test/java/com/seaofnodes/simple/Chapter10Test.java
@@ -1,6 +1,11 @@
 package com.seaofnodes.simple;
 
+import com.seaofnodes.simple.node.Node;
 import com.seaofnodes.simple.node.StopNode;
+import com.seaofnodes.simple.node.LoadNode;
+import com.seaofnodes.simple.node.StoreNode;
+import com.seaofnodes.simple.evaluator.Evaluator;
+import java.util.BitSet;
 import org.junit.Test;
 import static org.junit.Assert.assertEquals;
 import static org.junit.Assert.fail;
@@ -161,7 +166,7 @@ while (arg) {
 return bar.a;
 """);
         StopNode stop = parser.parse().iterate();
-        assertEquals("return Phi(Loop13,0,(Phi_a+2));", stop.toString());
+        assertEquals("return Phi(Loop15,0,(Phi_a+2));", stop.toString());
     }
 
     @Test
@@ -213,7 +218,7 @@ if( bar ) bar.a = 1;
 return bar;
 """);
         StopNode stop = parser.parse().iterate();
-        assertEquals("return Phi(Region33,(*void)Phi(Region20,null,Bar),null);", stop.toString());
+        assertEquals("return Phi(Region36,(*void)Phi(Region22,null,Bar),null);", stop.toString());
     }
 
     @Test
@@ -229,7 +234,7 @@ else bar.a = 1;
 return rez;
 """);
         StopNode stop = parser.parse().iterate();
-        assertEquals("return Phi(Region39,4,3);", stop.toString());
+        assertEquals("return Phi(Region42,4,3);", stop.toString());
     }
 
     @Test
@@ -283,7 +288,7 @@ while( i.x < i.len ) {
 return sum;
 """);
         StopNode stop = parser.parse().iterate();
-        assertEquals("return Phi(Loop18,0,(Phi(Loop,0,(Phi_x+1))+Phi_sum));", stop.toString());
+        assertEquals("return Phi(Loop19,0,(Phi(Loop,0,(Phi_x+1))+Phi_sum));", stop.toString());
     }
 
 
@@ -304,7 +309,7 @@ while(arg) {
 return ret;
 """);
         StopNode stop = parser.parse().iterate();
-        assertEquals("return Phi(Loop13,s0,Phi(Region37,s0,Phi_ret));", stop.toString());
+        assertEquals("return Phi(Loop15,s0,Phi(Region42,s0,Phi_ret));", stop.toString());
     }
 
     @Test
@@ -322,7 +327,7 @@ while(arg) {
 return ret;
 """);
         StopNode stop = parser.parse().iterate();
-        assertEquals("return Phi(Loop17,s0,Phi(Region38,s0,Phi_ret));", stop.toString());
+        assertEquals("return Phi(Loop21,s0,Phi(Region43,s0,Phi_ret));", stop.toString());
     }
 
 
@@ -339,7 +344,7 @@ while(arg < 10) {
 return ret;
 """);
         StopNode stop = parser.parse().iterate();
-        assertEquals("return Phi(Loop13,s0,Phi(Region35,s0,Phi_ret));", stop.toString());
+        assertEquals("return Phi(Loop15,s0,Phi(Region39,s0,Phi_ret));", stop.toString());
     }
 
     @Test
@@ -457,4 +462,120 @@ return 0;
         assertEquals("return 0;", stop.toString());
     }
 
+    @Test public void testReadBeforeStores() {
+        var stop = new Parser("""
+            struct S { int x; int y; }
+            S a = new S; S b = new S;
+            a.x = 11; b.x = 22;
+            S p = a; if (arg) p = b;
+            int before = p.x;
+            a.y = 55; b.y = 66;
+            a.x = 33; b.x = 44;
+            return before*100 + p.x;
+            """).parse().iterate();
+        assertEquals(1133L, com.seaofnodes.simple.evaluator.Evaluator.evaluate(stop,0));
+        assertEquals(2244L, com.seaofnodes.simple.evaluator.Evaluator.evaluate(stop,1));
+    }
+
+    static final String NESTED_MEMORY = """
+            struct S { int x; int y; int z; }
+            S s = new S;
+            s.x = 5; s.y = 7; s.z = 11;
+            while (arg > 0) {
+                s.x = s.x + 1;
+                int j = 3;
+                while (j > 0) {
+                    j = j - 1;
+                    if (j == 1) continue;
+                    s.y = s.y + arg;
+                    if (arg == 2) break;
+                    s.z = s.z + 1;
+                }
+                arg = arg - 1;
+            }
+            return s;
+            """;
+
+    @Test public void testMemoryAcrossNestedLoops() {
+        var stop = new Parser(NESTED_MEMORY).parse().iterate();
+        for (int arg=0; arg<7; arg++) {
+            var obj = (com.seaofnodes.simple.evaluator.Evaluator.Obj)
+                com.seaofnodes.simple.evaluator.Evaluator.evaluate(stop,arg);
+            org.junit.Assert.assertArrayEquals(new Object[] {
+                5L+arg, 7L+arg*(arg+1)-(arg>=2 ? 2 : 0), 11L+2*arg-(arg>=2 ? 2 : 0)
+            }, obj.fields());
+        }
+    }
+
+    @Test public void testMemoryAtEarlyReturns() {
+        var stop = new Parser("""
+            struct S { int x; int y; int z; }
+            S s = new S;
+            s.x = 3; s.y = 5; s.z = 7;
+            if (arg) { s.x = 11; s.z = 13; return s; }
+            s.y = 17;
+            return s;
+            """).parse().iterate();
+        for (int arg=0; arg<2; arg++) {
+            var obj = (com.seaofnodes.simple.evaluator.Evaluator.Obj)
+                com.seaofnodes.simple.evaluator.Evaluator.evaluate(stop,arg);
+            org.junit.Assert.assertArrayEquals(arg==0 ? new Object[]{3L,17L,7L} : new Object[]{11L,5L,13L}, obj.fields());
+        }
+    }
+
+    @Test public void testKeepLoadsAtMerge() {
+        StopNode stop = new Parser("""
+            struct S { int x; }
+            S a = new S; S b = new S;
+            a.x = arg; b.x = arg+1;
+            S p = a; S q = b;
+            if (arg<0) { p=b; q=a; }
+            int v;
+            if (arg>1) v=p.x; else v=q.x;
+            return v;
+            """).parse().iterate();
+        // The one-step safety check stops at the memory aggregate.
+        assertEquals(2,countMemoryNodes(stop,LoadNode.class,new BitSet()));
+        assertEquals(-1L,Evaluator.evaluate(stop,-1));
+        assertEquals(1L,Evaluator.evaluate(stop,0));
+        assertEquals(3L,Evaluator.evaluate(stop,3));
+    }
+
+    @Test public void testDropStores() {
+        StopNode stop = new Parser("""
+            struct S { int x; }
+            S s = new S;
+            if (arg) s.x=arg+1; else s.x=arg+2;
+            return s;
+            """).parse().iterate();
+        assertEquals(1,countMemoryNodes(stop,StoreNode.class,new BitSet()));
+        assertEquals(2L,((Evaluator.Obj)Evaluator.evaluate(stop,0)).fields()[0]);
+        assertEquals(4L,((Evaluator.Obj)Evaluator.evaluate(stop,3)).fields()[0]);
+    }
+
+    @Test public void testKeepReadsBeforeWrites() {
+        StopNode stop = new Parser("""
+            struct S { int x; int y; }
+            S a = new S; S b = new S;
+            a.x=arg; b.x=arg+1;
+            S p=a; S q=b;
+            if (arg<0) { p=b; q=a; }
+            int v;
+            if (arg>1) { v=p.x; p.x=41; p.y=5; }
+            else       { v=q.x; q.x=42; }
+            return v;
+            """).parse().iterate();
+        assertEquals(2,countMemoryNodes(stop,LoadNode.class,new BitSet()));
+        assertEquals(-1L,Evaluator.evaluate(stop,-1));
+        assertEquals(1L,Evaluator.evaluate(stop,0));
+        assertEquals(3L,Evaluator.evaluate(stop,3));
+    }
+
+    private static int countMemoryNodes(Node n, Class<?> kind, BitSet seen) {
+        if (n==null || seen.get(n._nid)) return 0;
+        seen.set(n._nid);
+        int cnt=kind.isInstance(n) ? 1 : 0;
+        for (Node def : n._inputs) cnt+=countMemoryNodes(def,kind,seen);
+        return cnt;
+    }
 }
diff --git a/chapter15/src/test/java/com/seaofnodes/simple/Chapter10bTest.java b/chapter15/src/test/java/com/seaofnodes/simple/Chapter10bTest.java
new file mode 100644
index 00000000..6f094cfb
--- /dev/null
+++ b/chapter15/src/test/java/com/seaofnodes/simple/Chapter10bTest.java
@@ -0,0 +1,64 @@
+package com.seaofnodes.simple;
+
+import com.seaofnodes.simple.node.*;
+import com.seaofnodes.simple.evaluator.Evaluator;
+import org.junit.Test;
+import static org.junit.Assert.*;
+
+public class Chapter10bTest {
+    @Test public void testIndependentField() {
+        var stop = new Parser("""
+            struct S { int x; int y; }
+            S s = new S;
+            s.x = 42;
+            while (arg > 0) { s.y = s.y + arg; arg = arg - 1; }
+            return s.x;
+            """).parse().iterate();
+        assertEquals("return 42;",stop.toString());
+        assertEquals(42L,Evaluator.evaluate(stop,5));
+        assertNull(stop.walk(n -> n instanceof LoadNode ? n : null));
+    }
+
+    @Test public void testParallelMemoryPhis() {
+        var stop = new Parser("""
+            struct S { int x; int y; int z; }
+            S a = new S; S b = new S;
+            S p = a; if (arg) p = b;
+            while (arg > 0) {
+                a.x = p.x + arg;
+                a.y = p.y + 2;
+                a.z = p.z + 3;
+                arg = arg - 1;
+            }
+            return a;
+            """).parse().iterate();
+        int[] phis = {0};
+        stop.walk(n -> {
+            if (n instanceof MemPhiNode) phis[0]++;
+            if (n instanceof MemMergeNode m && m.in(1) instanceof BulkMemPhiNode b)
+                for(int a=b._aliases.nextSetBit(0); a>=0; a=b._aliases.nextSetBit(a+1))
+                    assertTrue(a<m.nIns() && m.in(a)!=null);
+            assertFalse(n instanceof PhiNode && n.isMem() &&
+                !(n instanceof MemPhiNode) && !(n instanceof BulkMemPhiNode));
+            return null;
+        });
+        assertTrue(phis[0]>=3);
+        assertArrayEquals(new Object[]{1L,2L,3L},((Evaluator.Obj)Evaluator.evaluate(stop,4)).fields());
+    }
+
+    @Test public void testLateSliceWorklist() throws ReflectiveOperationException {
+        // Seed 97 exposed a store selecting a bulk predecessor without queuing
+        // it. Keep both the worklist assertion and the final heap check.
+        for (int seed : new int[]{0,97,123,456}) {
+            var parser = new Parser(Chapter10Test.NESTED_MEMORY);
+            var field = IterPeeps.class.getDeclaredField("WORK");
+            field.setAccessible(true);
+            Object work = field.get(null);
+            field = work.getClass().getDeclaredField("_R");
+            field.setAccessible(true);
+            ((java.util.Random)field.get(work)).setSeed(seed);
+            var stop = parser.parse().iterate();
+            assertArrayEquals(new Object[]{9L,25L,17L},((Evaluator.Obj)Evaluator.evaluate(stop,4)).fields());
+        }
+    }
+}
diff --git a/chapter15/src/test/java/com/seaofnodes/simple/Chapter11Test.java b/chapter15/src/test/java/com/seaofnodes/simple/Chapter11Test.java
index 76581308..3421340f 100644
--- a/chapter15/src/test/java/com/seaofnodes/simple/Chapter11Test.java
+++ b/chapter15/src/test/java/com/seaofnodes/simple/Chapter11Test.java
@@ -325,7 +325,7 @@ while( prime <= arg ) {
 return primeCount;
 """);
         StopNode stop = parser.parse().iterate();
-        assertEquals("Stop[ return 0; return Phi(Loop20,1,Phi(Region87,Phi_primeCount,Phi(Region81,(Phi_primeCount+1),Phi_primeCount))); ]", stop.toString());
+        assertEquals("Stop[ return 0; return Phi(Loop21,1,Phi(Region88,Phi_primeCount,Phi(Region82,(Phi_primeCount+1),Phi_primeCount))); ]", stop.toString());
         assertEquals(0L, Evaluator.evaluate(stop,  1)); // No primes 1 or below
         assertEquals(1L, Evaluator.evaluate(stop,  2)); // 2
         assertEquals(2L, Evaluator.evaluate(stop,  3)); // 2, 3
@@ -370,7 +370,7 @@ if (arg) {
 return i;
 """);
         StopNode stop = parser.parse().iterate();
-        assertEquals("return Phi(Region40,.f,0);", stop.toString());
+        assertEquals("return Phi(Region46,.f,0);", stop.toString());
     }
 
     @Test
@@ -477,7 +477,7 @@ while(arg) {
 return arg;
 """);
         StopNode stop = parser.parse().iterate();
-        assertEquals("return Phi(Loop17,arg,Phi(Region42,.f,0));", stop.toString());
+        assertEquals("return Phi(Loop21,arg,Phi(Region48,.f,0));", stop.toString());
     }
 
     @Test
diff --git a/chapter15/src/test/java/com/seaofnodes/simple/Chapter12Test.java b/chapter15/src/test/java/com/seaofnodes/simple/Chapter12Test.java
index 4eaf81df..998053ec 100644
--- a/chapter15/src/test/java/com/seaofnodes/simple/Chapter12Test.java
+++ b/chapter15/src/test/java/com/seaofnodes/simple/Chapter12Test.java
@@ -64,7 +64,7 @@ while( 1 ) {
 return guess;
 """);
         StopNode stop = parser.parse().iterate();
-        assertEquals("return Phi(Loop9,(flt)arg,(((ToFloat/Phi_guess)+Phi_guess)/2.0));", stop.toString());
+        assertEquals("return Phi(Loop10,(flt)arg,(((ToFloat/Phi_guess)+Phi_guess)/2.0));", stop.toString());
         assertEquals(3.0, Evaluator.evaluate(stop,  9));
         assertEquals(1.414213562373095, Evaluator.evaluate(stop,  2));
     }
diff --git a/chapter15/src/test/java/com/seaofnodes/simple/Chapter13Test.java b/chapter15/src/test/java/com/seaofnodes/simple/Chapter13Test.java
index daf981bd..3313e731 100644
--- a/chapter15/src/test/java/com/seaofnodes/simple/Chapter13Test.java
+++ b/chapter15/src/test/java/com/seaofnodes/simple/Chapter13Test.java
@@ -35,7 +35,7 @@ while( arg ) {
 return head.next.i;
 """);
         try { parser.parse().iterate(); fail(); }
-        catch( Exception e ) { assertEquals("Might be null accessing 'next'",e.getMessage()); }
+        catch( Exception e ) { assertEquals("Might be null accessing 'i'",e.getMessage()); }
     }
 
     @Test
diff --git a/chapter15/src/test/java/com/seaofnodes/simple/Chapter14Test.java b/chapter15/src/test/java/com/seaofnodes/simple/Chapter14Test.java
index 048cb93a..d64423de 100644
--- a/chapter15/src/test/java/com/seaofnodes/simple/Chapter14Test.java
+++ b/chapter15/src/test/java/com/seaofnodes/simple/Chapter14Test.java
@@ -59,7 +59,7 @@ while( b ) b = b + 456;// Truncate
 return b;
 """);
         StopNode stop = parser.parse().iterate();
-        assertEquals("return Phi(Loop9,123,((Phi_b+456)&255));", stop.toString());
+        assertEquals("return Phi(Loop10,123,((Phi_b+456)&255));", stop.toString());
     }
 
     @Test
diff --git a/chapter15/src/test/java/com/seaofnodes/simple/Chapter15Test.java b/chapter15/src/test/java/com/seaofnodes/simple/Chapter15Test.java
index 6ec7cc1a..8f9d2d14 100644
--- a/chapter15/src/test/java/com/seaofnodes/simple/Chapter15Test.java
+++ b/chapter15/src/test/java/com/seaofnodes/simple/Chapter15Test.java
@@ -12,6 +12,70 @@ import static org.junit.Assert.fail;
 
 public class Chapter15Test {
 
+    @Test public void testPartialAllocationMemory() {
+        StopNode stop = new Parser("""
+            struct Other { int a; int b; int c; }
+            struct S { int x; flt y; S? next; }
+            Other other = new Other;
+            other.c = 7;
+            S a = new S;
+            a.x = arg;
+            a.y = 1.5;
+            S b = new S;
+            // S's aliases are global identities, not tuple or input positions.
+            // Bypass b's zeroing for a, preserving the unrelated Other slice.
+            return a.x + a.y + b.x + b.y + other.c;
+            """).parse().iterate();
+        assertEquals(8.5, Evaluator.evaluate(stop,0));
+        assertEquals(12.5, Evaluator.evaluate(stop,4));
+
+        stop = new Parser("""
+            struct S { int x; flt y; S? next; }
+            S a = new S; S b = new S;
+            S p = a; if (arg) p = b;
+            // The memory result carries distinct int, float and pointer facts.
+            if (p.next != null) return 99;
+            return p.x + p.y;
+            """).parse().iterate();
+        assertEquals("return 0.0;",stop.toString());
+        assertEquals(0.0,Evaluator.evaluate(stop,1));
+    }
+
+    @Test public void testReadAcrossAllocation() {
+        StopNode stop = new Parser("""
+            struct S { int x; }
+            S a = new S; S b = new S;
+            a.x = 11; b.x = 22;
+            S p = a; if (arg) p = b;
+            int before = p.x;
+            S c = new S;
+            a.x = 33; b.x = 44;
+            // The partial input to c must not hide the read/write ordering.
+            // p can alias either object, so node inequality cannot bypass New.
+            return before*100 + p.x + c.x;
+            """).parse().iterate();
+        assertEquals(1133L,Evaluator.evaluate(stop,0));
+        assertEquals(2244L,Evaluator.evaluate(stop,1));
+    }
+
+    @Test public void testAllocationInLoop() {
+        StopNode stop = new Parser("""
+            struct S { int x; flt y; S? next; }
+            S old = new S; old.x = 7;
+            S last = old;
+            while (arg > 0) {
+                S fresh = new S;
+                fresh.x = last.x + 1;
+                fresh.next = last;
+                last = fresh;
+                arg = arg - 1;
+            }
+            return old.x*100 + last.x;
+            """).parse().iterate();
+        assertEquals(707L,Evaluator.evaluate(stop,0));
+        assertEquals(712L,Evaluator.evaluate(stop,5));
+    }
+
     @Test
     public void testJig() {
         Parser parser = new Parser("""
@@ -34,7 +98,7 @@ if (arg) {
 return b[0] + b[1];
 """);
         StopNode stop = parser.parse().iterate();
-        assertEquals("return Phi(Region69,1,0);", stop.toString());
+        assertEquals("return Phi(Region72,1,0);", stop.toString());
         assertEquals(0L, Evaluator.evaluate(stop,  0));
         assertEquals(1L, Evaluator.evaluate(stop,  1));
     }
@@ -151,7 +215,7 @@ else {
 return rez;
 """);
         StopNode stop = parser.parse().iterate();
-        assertEquals("return Phi(Region118,1.2,Phi(Region115,2.3,.y));", stop.toString());
+        assertEquals("return Phi(Region122,1.2,Phi(Region119,2.3,.y));", stop.toString());
         assertEquals(3.14, Evaluator.evaluate(stop, 0));
     }
 
diff --git a/chapter15/src/test/java/com/seaofnodes/simple/evaluator/Evaluator.java b/chapter15/src/test/java/com/seaofnodes/simple/evaluator/Evaluator.java
index 34921b94..9eed23de 100644
--- a/chapter15/src/test/java/com/seaofnodes/simple/evaluator/Evaluator.java
+++ b/chapter15/src/test/java/com/seaofnodes/simple/evaluator/Evaluator.java
@@ -187,7 +187,7 @@ public class Evaluator {
         Object[] body=null;
         int num;
         if( type.isAry() ) {
-            long sz = (Long)val(alloc.in(1));
+            long sz = (Long)val(alloc.size());
             long n = offToIdx(sz, type);
             if( n < 0 )
                 throw new NegativeArraySizeException(""+n);
@@ -215,11 +215,7 @@ public class Evaluator {
                 assert c instanceof TypeMemPtr;
             }
         }
-        Object[] mems = new Object[type._fields.length+2];
-        // mems[0] is control
-        mems[1] = new Obj(type,body); // the ref
-        // mems[2+...] are memory aliases
-        return mems;
+        return new Object[]{new Obj(type,body),MEMORY};
     }
 
     private Object load(LoadNode load) {
@@ -312,6 +308,7 @@ public class Evaluator {
             case ToFloatNode  cast  -> (double)vall(cast.in(1));
             case LoadNode     load  -> load(load);
             case StoreNode    store -> store(store);
+            case MemMergeNode merge -> MEMORY;
             case NewNode      alloc -> alloc(alloc);
             case CProjNode    cproj -> ((Object[])val(cproj.ctrl()))[cproj._idx];
             case ProjNode     proj  -> ((Object[])val( proj.in(0) ))[ proj._idx];
@@ -325,8 +322,8 @@ public class Evaluator {
     public Object evaluate(long parameter, int loops) {
         if (start == null) return Status.TIMEOUT;
         var s = new Object[start.compute()._types.length];
-        s[1] = parameter;
-        for(int i=2;i<s.length;i++) s[i] = MEMORY;
+        s[1] = MEMORY;
+        s[2] = parameter;
         values[start._nid] = s;
         int i=0;
         Scheduler.Block block = this.startBlock;
@@ -337,7 +334,7 @@ public class Evaluator {
                 case null:
                     return Status.FALLTHROUGH;
                 case ReturnNode ret:
-                    return val(ret.in(1));
+                    return val(ret.expr());
                 case IfNode ifn:
                     block = block.next()[isTrue(val(ifn.in(1))) ? 0 : 1];
                     if (block == null) return Status.FALLTHROUGH;
diff --git a/chapter15/src/test/java/com/seaofnodes/simple/evaluator/Scheduler.java b/chapter15/src/test/java/com/seaofnodes/simple/evaluator/Scheduler.java
index 59c15d3f..125f2f5e 100644
--- a/chapter15/src/test/java/com/seaofnodes/simple/evaluator/Scheduler.java
+++ b/chapter15/src/test/java/com/seaofnodes/simple/evaluator/Scheduler.java
@@ -31,6 +31,8 @@ import java.util.*;
  */
 public class Scheduler {
 
+    private final HashMap<Node,ArrayList<NodeData>> readers = new HashMap<>();
+
     /**
      * A basic block with a schedule of the containing nodes.
      *
@@ -252,7 +254,7 @@ public class Scheduler {
                 // but they did not refine the placement
                 // so do that now.
                 var mem = l.in(1);
-                for(var out : mem._outputs) {
+                for(var out : l.antiDeps()) {
                     if (out instanceof PhiNode p) {
                         var r = p.in(0);
                         for (int i = 1; i < p.nIns(); i++) {
@@ -270,13 +272,9 @@ public class Scheduler {
             for(var in:data.node._inputs) {
                 if (in!=null) update(d(in), data.block);
             }
-            if (data.node instanceof StoreNode s) {
-                // Store nodes have anti-deps to load nodes.
-                // So decrease the uses of these loads when the store is placed.
-                for (var out: s.in(1)._outputs) {
-                    if (out instanceof LoadNode) od(out).ifPresent(this::decUsers);
-                }
-            }
+            var loads = readers.get(data.node);
+            if (loads != null)
+                for (var load : loads) decUsers(load);
         }
 
         // Now all nodes should be placed and have a block assigned
@@ -442,7 +440,6 @@ public class Scheduler {
     private void doMarkAlive(Node node) {
         var cfgQueue = new Stack<NodeData>();
         var dataQueue = new Stack<NodeData>();
-        var mem = new Stack<NodeData>();
         markAlive(cfgQueue, node, true);
         // Mark all CFG nodes.
         while (!cfgQueue.isEmpty()) {
@@ -467,16 +464,16 @@ public class Scheduler {
             } else {
                 for (var in : node._inputs) if (in != null && !(in instanceof CFGNode)) markAlive(dataQueue, in, false);
             }
-            if (node instanceof StoreNode) mem.push(data);
-        }
-        // Handle store nodes and increase load with an anti-dep to the store.
-        while (!mem.isEmpty()) {
-            var data = mem.pop();
-            node = data.node;
-            for(var out:node.in(1)._outputs) {
-                if (out instanceof LoadNode) od(out).ifPresent(d->d.users++);
-            }
         }
+        // Writes, including New behind an aggregate, schedule before their
+        // anti-dependent reads in this reverse scheduling pass.
+        for (var load : data.values())
+            if (load.node instanceof LoadNode l)
+                for (var use : l.antiDeps())
+                    if ((use instanceof StoreNode || use instanceof NewNode) && data.containsKey(use)) {
+                        load.users++;
+                        readers.computeIfAbsent(use,k->new ArrayList<>()).add(load);
+                    }
     }
 
     /**