hash.c: init table with size

* hash.c (rb_hash_s_create): allocate internal table with the
  given size.

git-svn-id: svn+ssh://ci.ruby-lang.org/ruby/trunk@54435 b2dd03c8-39d4-4d8f-98ff-823fe69b080e

hash.c

@@ -692,6 +692,9 @@ rb_hash_s_create(int argc, VALUE *argv, VALUE klass)
     }
 
     hash = hash_alloc(klass);
+    if (argc > 0) {
+        RHASH(hash)->ntbl = st_init_table_with_size(&objhash, argc / 2);
+    }
     for (i=0; i<argc; i+=2) {
         rb_hash_aset(hash, argv[i], argv[i + 1]);
     }