From c5ef4e52fd7d183861b33476db999fa04f777607 Mon Sep 17 00:00:00 2001
From: Cliff Click <cliffc@acm.org>
Date: Sun, 27 Sep 2026 08:52:12 -0700
Subject: Remove -disablePeephole

---
 chapter03/README.md                                           |  5 +++--
 chapter03/src/main/java/com/seaofnodes/simple/node/Node.java  | 11 +----------
 .../src/test/java/com/seaofnodes/simple/Chapter02Test.java    |  4 +---
 .../src/test/java/com/seaofnodes/simple/Chapter03Test.java    |  9 ---------
 4 files changed, 5 insertions(+), 24 deletions(-)

(limited to 'chapter03')

diff --git a/chapter03/README.md b/chapter03/README.md
index ddb9fafa..39baf903 100644
--- a/chapter03/README.md
+++ b/chapter03/README.md
@@ -124,8 +124,9 @@ The variables `a`, `b`, and `c` are registered in this table.
 * On line 5, a variable `b` is declared. `b` is registered in the symbol table at level 1. This then
 hides the variable with the same name on line 2.
 * On line 7, we update the variable `c`. Variable lookup will find it in the symbol table at level 0.
-The node graph is shown below (note that peephole opts are switched off here so that we can
-see the graph as its initially constructed).
+The schematic below shows the variable bindings and arithmetic before constant
+folding. The compiler applies peepholes as it builds the graph, so the actual
+result of this example is `return 4;`.
 
 ![Graph1](./docs/03-graph1.svg)
 
diff --git a/chapter03/src/main/java/com/seaofnodes/simple/node/Node.java b/chapter03/src/main/java/com/seaofnodes/simple/node/Node.java
index 3922533c..3fa0fd1e 100644
--- a/chapter03/src/main/java/com/seaofnodes/simple/node/Node.java
+++ b/chapter03/src/main/java/com/seaofnodes/simple/node/Node.java
@@ -210,12 +210,6 @@ public abstract class Node {
 
     // Mostly used for asserts and printing.
     public boolean isDead() { return isUnused() && nIns()==0 && _type==null; }
-    /**
-     * We allow disabling peephole opt so that we can observe the
-     * full graph, vs the optimized graph.
-     */
-    public static boolean _disablePeephole = false;
-
     /**
      * Try to peephole at this node and return a better replacement Node if
      * possible.  We compute a {@link Type} and then check and replace:
@@ -241,9 +235,6 @@ public abstract class Node {
         // Compute initial or improved Type
         Type type = _type = compute();
 
-        if (_disablePeephole)
-            return null;        // Peephole optimizations turned off
-
         // Replace constant computations from non-constants with a constant node
         if (!(this instanceof ConstantNode) && type.isConstant()) {
             kill();             // Kill `this` because replacing with a Constant
@@ -283,7 +274,7 @@ public abstract class Node {
      * Used to allow repeating tests in the same JVM.  This just resets the
      * Node unique id generator, and is done as part of making a new Parser.
      */
-    public static void reset() { UNIQUE_ID = 1; _disablePeephole=false; }
+    public static void reset() { UNIQUE_ID = 1; }
 
     /**
      * Debugging utility to find a Node by index
diff --git a/chapter03/src/test/java/com/seaofnodes/simple/Chapter02Test.java b/chapter03/src/test/java/com/seaofnodes/simple/Chapter02Test.java
index 9de09d21..6c816a23 100644
--- a/chapter03/src/test/java/com/seaofnodes/simple/Chapter02Test.java
+++ b/chapter03/src/test/java/com/seaofnodes/simple/Chapter02Test.java
@@ -11,10 +11,8 @@ public class Chapter02Test {
     @Test
     public void testParseGrammar() {
         Parser parser = new Parser("return 1+2*3+-5;");
-        Node._disablePeephole = true; // disable peephole so we can observe full graph
         ReturnNode ret = parser.parse();
-        assertEquals("return (1+((2*3)+(-5)));", ret.print());
-        Node._disablePeephole = false;
+        assertEquals("return 2;", ret.print());
     }
 
     @Test
diff --git a/chapter03/src/test/java/com/seaofnodes/simple/Chapter03Test.java b/chapter03/src/test/java/com/seaofnodes/simple/Chapter03Test.java
index b42f1433..78696633 100644
--- a/chapter03/src/test/java/com/seaofnodes/simple/Chapter03Test.java
+++ b/chapter03/src/test/java/com/seaofnodes/simple/Chapter03Test.java
@@ -28,15 +28,6 @@ public class Chapter03Test {
         assertEquals("return 4;", ret.print());
     }
 
-    @Test
-    public void testVarScopeNoPeephole() {
-        Parser parser = new Parser("int a=1; int b=2; int c=0; { int b=3; c=a+b;  } return c; ");
-        Node._disablePeephole = true;
-        ReturnNode ret = parser.parse();
-        Node._disablePeephole = false;
-        assertEquals("return (1+3);", ret.print());
-    }
-
     @Test
     public void testVarDist() {
         Parser parser = new Parser("int x0=1; int y0=2; int x1=3; int y1=4; return (x0-x1)*(x0-x1) + (y0-y1)*(y0-y1); ");
-- 
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