diff --git a/lib/intruby.rb b/lib/intruby.rb
index 53860cf..cafd54c 100644
--- a/lib/intruby.rb
+++ b/lib/intruby.rb
@@ -17,12 +17,15 @@ module IntRuby
   include LLVMUtil
 
   def gen_ivar_ptr(builder)
-    ftype = Type.function(P_VALUE, [VALUE, VALUE])
+    ftype = Type.function(P_VALUE, [VALUE, VALUE, P_VALUE])
     b = builder.define_function_raw('llvm_ivar_ptr', ftype)
     args = builder.arguments
     embed = builder.create_block
     nonembed = builder.create_block
     comm = builder.create_block
+    cachehit = builder.create_block
+    cachemiss = builder.create_block
+
     rbp = Type.pointer(RBASIC)
     slfop = b.int_to_ptr(args[0], Type.pointer(ROBJECT))
     slf = b.int_to_ptr(args[0], rbp)
@@ -56,8 +59,8 @@ def gen_ivar_ptr(builder)
     niv_index_tbl = b.load(ivitp)
 
     b.br(comm)
-
     b.set_insert_point(comm)
+
     ptr = b.phi(P_VALUE)
     ptr.add_incoming(eptr, embed)
     ptr.add_incoming(nptr, nonembed)
@@ -66,6 +69,20 @@ def gen_ivar_ptr(builder)
     iv_index_tbl.add_incoming(eiv_index_tbl, embed)
     iv_index_tbl.add_incoming(niv_index_tbl, nonembed)
 
+    oldindex = b.load(args[2])
+    ishit = b.icmp_ne(oldindex, -1.llvm)
+
+    b.cond_br(ishit, cachehit, cachemiss)
+
+    # Inline Cache hit
+    b.set_insert_point(cachehit)
+    index = b.load(args[2])
+    resp = b.gep(ptr, index)
+    b.return(resp)
+
+    # Inline Cache Misss
+    b.set_insert_point(cachemiss)
+
 
     indexp = b.alloca(VALUE, 1)
 
@@ -75,8 +92,9 @@ def gen_ivar_ptr(builder)
     
     index = b.load(indexp)
     resp = b.gep(ptr, index)
+
+    b.store(index, args[2])
     b.return(resp)
-    
   end
 end
 end
diff --git a/lib/llvmutil.rb b/lib/llvmutil.rb
index 0f62fb6..847d456 100644
--- a/lib/llvmutil.rb
+++ b/lib/llvmutil.rb
@@ -107,8 +107,7 @@ def gen_call_var_args_common(para, fname, rtype, ftype)
   end
 
   def add_global_variable(name, type, init)
-    @global_malloc_area_tab[name] = [type, init]
-    @global_malloc_area_tab.size - 1
+    @builder.define_global_variable(type, init)
   end
 
   def gen_binary_operator(para, core)
diff --git a/lib/methoddef_ex.rb b/lib/methoddef_ex.rb
index 7c2b7fa..e721da5 100644
--- a/lib/methoddef_ex.rb
+++ b/lib/methoddef_ex.rb
@@ -15,13 +15,11 @@ module MethodDefinition
         lambda {|para|
           info = para[:info]
           rettype = RubyType.fixnum(info[3], "Return type of gen_interval_cycle")
-          glno = add_global_variable("interval_cycle", 
+          prevvalp = add_global_variable("interval_cycle", 
                                      Type::Int64Ty, 
                                      0.llvm(Type::Int64Ty))
           @expstack.push [rettype,
             lambda {|b, context|
-              prevvalp = context.builder.global_variable
-              prevvalp = b.struct_gep(prevvalp, glno)
               prevval = b.load(prevvalp)
               ftype = Type.function(Type::Int64Ty, [])
               fname = 'llvm.readcyclecounter'
diff --git a/lib/vmtraverse.rb b/lib/vmtraverse.rb
index 0b34d7b..437fb68 100644
--- a/lib/vmtraverse.rb
+++ b/lib/vmtraverse.rb
@@ -179,7 +179,7 @@ def initialize(iseq, bind, preload)
     }
 
     # Information of global variables by malloc
-    @global_malloc_area_tab = {}
+    @global_malloc_area_tab = []
 
     # Number of trace(for profile speed up)
     @trace_no = 0
@@ -374,11 +374,15 @@ def visit_block_start(code, ins, local_vars, ln, info)
         if cnt > 0 and 
            OPTION[:cache_instance_variable] and 
            info[1] != :initialize then
-          ftype = Type.function(P_VALUE, [VALUE, VALUE])
+
+          # define inline cache area
+          oldindex = add_global_variable("old_index", VALUE, -1.llvm)
+          ftype = Type.function(P_VALUE, [VALUE, VALUE, P_VALUE])
           func = context.builder.get_or_insert_function_raw('llvm_ivar_ptr', ftype)
           ivid = ((key.object_id << 1) / RVALUE_SIZE)
           slf = b.load(context.local_vars[2][:area])
-          vptr = b.call(func, slf, ivid.llvm)
+
+          vptr = b.call(func, slf, ivid.llvm, oldindex)
           context.instance_vars_local_area[key] = vptr
         else
           context.instance_vars_local_area[key] = nil
@@ -2364,17 +2368,7 @@ def gen_init_ruby(builder)
     b = builder.define_function_raw('init_ruby', ftype)
     initfunc = builder.current_function
     member = []
-    @global_malloc_area_tab.each do |vname, val|
-      member.push val[0]
-    end
-    type = Type.struct(member)
-
     initarg = []
-    @global_malloc_area_tab.each do |vname, val|
-      initarg.push val[1]
-    end
-    init = Value.get_struct_constant(type, *initarg)
-    gl = builder.define_global_variable(type, init)
 
     @generated_define_func.each do |klass, defperklass|
       if klass then
diff --git a/lib/yarv2llvm.rb b/lib/yarv2llvm.rb
index 24be3f9..b66ce9a 100644
--- a/lib/yarv2llvm.rb
+++ b/lib/yarv2llvm.rb
@@ -92,6 +92,7 @@ def llvm
 module LLVM::RubyInternals
   RFLOAT = Type.struct([RBASIC, Type::DoubleTy])
   P_RFLOAT = Type.pointer(RFLOAT)
+  P_P_VALUE = Type.pointer(P_VALUE)
 end
 
 =begin
diff --git a/sample/ao-render.rb b/sample/ao-render.rb
index 72aa360..ace73a7 100644
--- a/sample/ao-render.rb
+++ b/sample/ao-render.rb
@@ -1,4 +1,4 @@
-# AO rebder benchmark 
+# AO render benchmark 
 # Original program (C) Syoyo Fujita in Javascript (and other languages)
 #      http://lucille.atso-net.jp/blog/?p=642
 #      http://lucille.atso-net.jp/blog/?p=711