diff --git a/ChangeLog b/ChangeLog
index 874b081..f4736c9 100644
--- a/ChangeLog
+++ b/ChangeLog
@@ -1,3 +1,17 @@
+Mon May 11 01:40:28 2009  Minero Aoki  <aamine@loveruby.net>
+
+	* net/loveruby/cflat/sysdep/x86/CodeGenerator.java: use
+	  PeepholeOptimizer directly.
+
+	* net/loveruby/cflat/asm/PeepholeOptimizer.java ->
+	  net/loveruby/cflat/sysdep/x86
+
+	* net/loveruby/cflat/asm/AsmOptimizer.java: removed.
+
+	* net/loveruby/cflat/codegenerator/CodeGeneratorOptions.java:
+	  should not provide PeepholeOptimizer, just provide
+	  optimizationLevel.
+
 Mon May 11 01:31:29 2009  Minero Aoki  <aamine@loveruby.net>
 
 	* net/loveruby/cflat/compiler/Compiler.java: move dumper code to
diff --git a/ToDo b/ToDo
index ecf087d..20cf266 100644
--- a/ToDo
+++ b/ToDo
@@ -9,6 +9,7 @@
 - refactoring: remove CodeGenerator.stackGrowsLower
 - refactoring: remove AssemblyFile stack.
 - refactoring: remove CodeGenerator#compileLHS (resolve in IR generation)
+- refactoring: CodeGeneratorOptions should not provide PeepholeOptimizer
 * refactoring: classify Linker
 * refactoring: classify Assembler
 
diff --git a/net/loveruby/cflat/asm/AsmOptimizer.java b/net/loveruby/cflat/asm/AsmOptimizer.java
deleted file mode 100644
index cfb30e1..0000000
--- a/net/loveruby/cflat/asm/AsmOptimizer.java
+++ /dev/null
@@ -1,6 +0,0 @@
-package net.loveruby.cflat.asm;
-import java.util.List;
-
-public interface AsmOptimizer {
-    public List<Assembly> optimize(List<Assembly> assemblies);
-}
diff --git a/net/loveruby/cflat/codegenerator/CodeGeneratorOptions.java b/net/loveruby/cflat/codegenerator/CodeGeneratorOptions.java
index 0b22f5b..36225e3 100644
--- a/net/loveruby/cflat/codegenerator/CodeGeneratorOptions.java
+++ b/net/loveruby/cflat/codegenerator/CodeGeneratorOptions.java
@@ -1,6 +1,4 @@
 package net.loveruby.cflat.codegenerator;
-import net.loveruby.cflat.asm.*;
-import java.util.*;
 
 public class CodeGeneratorOptions {
     protected int optimizeLevel;
@@ -19,19 +17,8 @@ public class CodeGeneratorOptions {
         this.optimizeLevel = level;
     }
 
-    public AsmOptimizer optimizer() {
-        if (optimizeLevel > 0) {
-            return PeepholeOptimizer.defaultSet();
-        }
-        else {
-            return new NullOptimizer();
-        }
-    }
-
-    class NullOptimizer implements AsmOptimizer {
-        public List<Assembly> optimize(List<Assembly> asms) {
-            return asms;
-        }
+    public int optimizeLevel() {
+        return optimizeLevel;
     }
 
     public void generateVerboseAsm() {
diff --git a/net/loveruby/cflat/sysdep/x86/CodeGenerator.java b/net/loveruby/cflat/sysdep/x86/CodeGenerator.java
index 1840cff..b8b07f2 100644
--- a/net/loveruby/cflat/sysdep/x86/CodeGenerator.java
+++ b/net/loveruby/cflat/sysdep/x86/CodeGenerator.java
@@ -381,8 +381,7 @@ class CodeGenerator
     private void compileFunctionBody(
             AssemblyFile file, DefinedFunction func) {
         AssemblyFile body = compileStmts(func);
-        List<Assembly> bodyAsms =
-                options.optimizer().optimize(body.assemblies());
+        List<Assembly> bodyAsms = optimize(body.assemblies());
         AsmStatistics stats = AsmStatistics.collect(bodyAsms);
         bodyAsms = reduceLabels(bodyAsms, stats);
         List<Register> saveRegs = usedCalleeSavedRegistersWithoutBP(stats);
@@ -409,6 +408,14 @@ class CodeGenerator
     }
     // #@@}
 
+    // #@@range/compileFunctionBody{
+    private List<Assembly> optimize(List<Assembly> asms) {
+        if (options.optimizeLevel() < 1) {
+            return asms;
+        }
+        return new PeepholeOptimizer().optimize(asms);
+    }
+
     private void printStackFrameLayout(
             AssemblyFile file,
             long saveRegsBytes, long lvarBytes, long maxTmpBytes,
diff --git a/net/loveruby/cflat/asm/PeepholeOptimizer.java b/net/loveruby/cflat/sysdep/x86/PeepholeOptimizer.java
similarity index 93%
rename from net/loveruby/cflat/asm/PeepholeOptimizer.java
rename to net/loveruby/cflat/sysdep/x86/PeepholeOptimizer.java
index 1a1b3c9..47b733f 100644
--- a/net/loveruby/cflat/asm/PeepholeOptimizer.java
+++ b/net/loveruby/cflat/sysdep/x86/PeepholeOptimizer.java
@@ -1,9 +1,10 @@
-package net.loveruby.cflat.asm;
+package net.loveruby.cflat.sysdep.x86;
+import net.loveruby.cflat.asm.*;
 import net.loveruby.cflat.utils.Cursor;
 import java.util.*;
 
-public class PeepholeOptimizer implements AsmOptimizer {
-    protected Map<String, List<Filter>> filterSet;
+public class PeepholeOptimizer {
+    private Map<String, List<Filter>> filterSet;
 
     public PeepholeOptimizer() {
         this.filterSet = new HashMap<String, List<Filter>>();
@@ -42,7 +43,7 @@ public class PeepholeOptimizer implements AsmOptimizer {
         return result;
     }
 
-    protected Filter matchFilter(Cursor<Assembly> asms) {
+    private Filter matchFilter(Cursor<Assembly> asms) {
         Instruction insn = (Instruction)asms.current();
         List<Filter> filters = filterSet.get(insn.mnemonic());
         if (filters == null) return null;
@@ -61,7 +62,7 @@ public class PeepholeOptimizer implements AsmOptimizer {
         return set;
     }
 
-    protected void loadDefaultFilters() {
+    private void loadDefaultFilters() {
         PeepholeOptimizer set = this;
 
         // mov
@@ -168,11 +169,11 @@ public class PeepholeOptimizer implements AsmOptimizer {
         set.add(new JumpEliminationFilter());
     }
 
-    protected ImmediateValue imm(long n) {
+    private ImmediateValue imm(long n) {
         return new ImmediateValue(n);
     }
 
-    protected OperandPattern reg() {
+    private OperandPattern reg() {
         return new AnyRegisterPattern();
     }
 
@@ -187,8 +188,8 @@ public class PeepholeOptimizer implements AsmOptimizer {
     //
 
     class SingleInsnFilter extends Filter {
-        protected InsnPattern pattern;
-        protected InsnTransform transform;
+        private InsnPattern pattern;
+        private InsnTransform transform;
 
         public SingleInsnFilter(InsnPattern pattern, InsnTransform transform) {
             this.pattern = pattern;
@@ -215,9 +216,9 @@ public class PeepholeOptimizer implements AsmOptimizer {
     }
 
     class InsnPattern {
-        protected String name;
-        protected OperandPattern pattern1;
-        protected OperandPattern pattern2;
+        private String name;
+        private OperandPattern pattern1;
+        private OperandPattern pattern2;
 
         InsnPattern(String name, OperandPattern pat1, OperandPattern pat2) {
             this.name = name;
@@ -250,7 +251,7 @@ public class PeepholeOptimizer implements AsmOptimizer {
         public JumpEliminationFilter() {
         }
 
-        protected String[] jmpInsns() {
+        private String[] jmpInsns() {
             return new String[] { "jmp", "jz", "jne", "je", "jne" };
         }
 
@@ -279,7 +280,7 @@ public class PeepholeOptimizer implements AsmOptimizer {
          *          mov
          *          add
          */
-        protected boolean doesLabelFollows(Cursor<Assembly> asms, Symbol jmpDest) {
+        private boolean doesLabelFollows(Cursor<Assembly> asms, Symbol jmpDest) {
             while (asms.hasNext()) {
                 Assembly asm = asms.next();
                 if (asm.isLabel()) {