* bignum.c (power_cache_get_power): Hide cached Bignum objects.

git-svn-id: svn+ssh://ci.ruby-lang.org/ruby/trunk@42306 b2dd03c8-39d4-4d8f-98ff-823fe69b080e

ChangeLog

@@ -1,3 +1,7 @@
+Thu Aug  1 20:46:29 2013  Tanaka Akira  <akr@fsij.org>
+
+	* bignum.c (power_cache_get_power): Hide cached Bignum objects.
+
 Thu Aug  1 19:15:05 2013  Tanaka Akira  <akr@fsij.org>
 
 	* bignum.c (rb_big2str1): Remove non-trim mode.

bignum.c

@@ -4151,6 +4151,7 @@ power_cache_get_power(int base, int power_level, size_t *numdigits_ret)
             power = bigsq(power_cache_get_power(base, power_level - 1, &numdigits));
             numdigits *= 2;
         }
+        rb_obj_hide(power);
         big2str_power_cache[base - 2][power_level] = power;
         big2str_numdigits_cache[base - 2][power_level] = numdigits;
 	rb_gc_register_mark_object(power);