diff --git a/ChangeLog b/ChangeLog
index b859561d90..453101bb9e 100644
--- a/ChangeLog
+++ b/ChangeLog
@@ -1,3 +1,8 @@
+Wed Jun 29 15:18:28 2016  NARUSE, Yui  <naruse@ruby-lang.org>
+
+	* insns.def (opt_succ): optimize like r55515. (but this argument is
+	  consntant)
+
 Wed Jun 29 12:41:58 2016  Shugo Maeda  <shugo@ruby-lang.org>
 
 	* test/ruby/test_refinement.rb: skip
diff --git a/insns.def b/insns.def
index 6a3a39cae8..7f7e3a07f8 100644
--- a/insns.def
+++ b/insns.def
@@ -2041,12 +2041,12 @@ opt_succ
     if (SPECIAL_CONST_P(recv)) {
 	if (FIXNUM_P(recv) &&
 	    BASIC_OP_UNREDEFINED_P(BOP_SUCC, INTEGER_REDEFINED_OP_FLAG)) {
-	    const VALUE obj = INT2FIX(1);
 	    /* fixnum + INT2FIX(1) */
-	    val = (recv + (obj & (~1)));
-	    if ((~(recv ^ obj) & (recv ^ val)) & ((unsigned long)LONG_MAX + 1)) {
-		val = rb_big_plus(rb_int2big(FIX2LONG(recv)),
-				  rb_int2big(FIX2LONG(obj)));
+	    if (recv != LONG2FIX(FIXNUM_MAX)) {
+		val = recv - 1 + INT2FIX(1);
+	    }
+	    else {
+		val = LONG2NUM(FIXNUM_MAX + 1);
 	    }
 	}
 	else {