diff --git a/ChangeLog b/ChangeLog
index d1cf9a00dc..7765672839 100644
--- a/ChangeLog
+++ b/ChangeLog
@@ -1,3 +1,10 @@
+Sun Dec  8 10:45:05 2013  Aman Gupta <ruby@tmm1.net>
+
+	* hash.c (hash_aset_str): revert r43870 due to performance issue
+	  [Bug #9188] [ruby-core:58730]
+	* parse.y (assoc): convert literal string hash keys to fstrings
+	* test/ruby/test_hash.rb (class TestHash): expand test
+
 Sun Dec  8 10:22:38 2013  Aman Gupta <ruby@tmm1.net>
 
 	* parse.y (register_symid_str): use fstrings in symbol table
diff --git a/hash.c b/hash.c
index a52e02ff67..1321b83191 100644
--- a/hash.c
+++ b/hash.c
@@ -1288,9 +1288,7 @@ static int
 hash_aset_str(st_data_t *key, st_data_t *val, struct update_arg *arg, int existing)
 {
     if (!existing) {
-	VALUE str = (VALUE)*key;
-	if (!OBJ_FROZEN(str))
-	    *key = rb_fstring(str);
+	*key = rb_str_new_frozen(*key);
     }
     return hash_aset(key, val, arg, existing);
 }
diff --git a/parse.y b/parse.y
index 2a0c5c64f7..d04cf45612 100644
--- a/parse.y
+++ b/parse.y
@@ -4912,6 +4912,10 @@ assocs		: assoc
 assoc		: arg_value tASSOC arg_value
 		    {
 		    /*%%%*/
+			if (nd_type($1) == NODE_STR) {
+			    nd_set_type($1, NODE_LIT);
+			    $1->nd_lit = rb_fstring($1->nd_lit);
+			}
 			$$ = list_append(NEW_LIST($1), $3);
 		    /*%
 			$$ = dispatch2(assoc_new, $1, $3);
diff --git a/test/ruby/test_hash.rb b/test/ruby/test_hash.rb
index 6aaba469db..4244b86b56 100644
--- a/test/ruby/test_hash.rb
+++ b/test/ruby/test_hash.rb
@@ -209,10 +209,11 @@ class TestHash < Test::Unit::TestCase
     assert_equal(256,     h[z])
   end
 
-  def test_ASET_string
+  def test_NEWHASH_fstring_key
     a = {"ABC" => :t}
     b = {"ABC" => :t}
     assert_same a.keys[0], b.keys[0]
+    assert_same "ABC".freeze, a.keys[0]
   end
 
   def test_EQUAL # '=='