diff --git a/ChangeLog b/ChangeLog
index 5e423d37cc..4c1bbe7215 100644
--- a/ChangeLog
+++ b/ChangeLog
@@ -1,3 +1,10 @@
+Wed Dec 17 10:18:42 2014  Koichi Sasada  <ko1@atdot.net>
+
+	* compile.c (iseq_compile_each): check
+	  iseq->compile_data->option->specialized_instruction for opt_* insn.
+
+	* test/ruby/test_iseq.rb: check no specialized_instructions option.
+
 Wed Dec 17 09:48:57 2014  Eric Wong  <e@80x24.org>
 
 	* compile.c (iseq_compile_each): only emit opt_str_freeze,
diff --git a/compile.c b/compile.c
index 8672c0e980..393590e00d 100644
--- a/compile.c
+++ b/compile.c
@@ -4406,8 +4406,8 @@ iseq_compile_each(rb_iseq_t *iseq, LINK_ANCHOR *ret, NODE * node, int poped)
 	 */
 	if (node->nd_recv && nd_type(node->nd_recv) == NODE_STR &&
 	    node->nd_mid == idFreeze && node->nd_args == NULL &&
-	    iseq->compile_data->current_block == Qfalse)
-	{
+	    iseq->compile_data->current_block == Qfalse &&
+	    iseq->compile_data->option->specialized_instruction) {
 	    VALUE str = rb_fstring(node->nd_recv->nd_lit);
 	    iseq_add_mark_object(iseq, str);
 	    ADD_INSN1(ret, line, opt_str_freeze, str);
@@ -4422,8 +4422,8 @@ iseq_compile_each(rb_iseq_t *iseq, LINK_ANCHOR *ret, NODE * node, int poped)
 	if (node->nd_mid == idAREF && !private_recv_p(node) && node->nd_args &&
 	    nd_type(node->nd_args) == NODE_ARRAY && node->nd_args->nd_alen == 1 &&
 	    nd_type(node->nd_args->nd_head) == NODE_STR &&
-	    iseq->compile_data->current_block == Qfalse)
-	{
+	    iseq->compile_data->current_block == Qfalse &&
+	    iseq->compile_data->option->specialized_instruction) {
 	    VALUE str = rb_fstring(node->nd_args->nd_head->nd_lit);
 	    node->nd_args->nd_head->nd_lit = str;
 	    COMPILE(ret, "recv", node->nd_recv);
@@ -5419,7 +5419,8 @@ iseq_compile_each(rb_iseq_t *iseq, LINK_ANCHOR *ret, NODE * node, int poped)
 	if (node->nd_mid == idASET && !private_recv_p(node) && node->nd_args &&
 	    nd_type(node->nd_args) == NODE_ARRAY && node->nd_args->nd_alen == 2 &&
 	    nd_type(node->nd_args->nd_head) == NODE_STR &&
-	    iseq->compile_data->current_block == Qfalse)
+	    iseq->compile_data->current_block == Qfalse &&
+	    iseq->compile_data->option->specialized_instruction)
 	{
 	    VALUE str = rb_fstring(node->nd_args->nd_head->nd_lit);
 	    node->nd_args->nd_head->nd_lit = str;
diff --git a/test/ruby/test_iseq.rb b/test/ruby/test_iseq.rb
index d7d15c7703..ede333fd14 100644
--- a/test/ruby/test_iseq.rb
+++ b/test/ruby/test_iseq.rb
@@ -124,4 +124,14 @@ class TestISeq < Test::Unit::TestCase
            ISeq.of(c.instance_method(:foobar)).label
     assert_same a, b
   end
+
+  def test_diable_opt
+    src = "a['foo'] = a['bar']; 'a'.freeze"
+    _,_,_,_,_,_,_,_,_,_,_,_,_,body= RubyVM::InstructionSequence.compile(src, __FILE__, __FILE__, __LINE__, false).to_a
+    body.each{|insn|
+      next if Integer === insn
+      op = insn.first
+      assert(!op.to_s.match(/^opt_/), "#{op}")
+    }
+  end
 end