digest.c: call to_s once

* ext/digest/digest.c (rb_digest_instance_equal): no need to call
  `to_s` twice.  [Bug #9913]

git-svn-id: svn+ssh://ci.ruby-lang.org/ruby/trunk@46371 b2dd03c8-39d4-4d8f-98ff-823fe69b080e

ChangeLog

@@ -1,3 +1,8 @@
+Sat Jun  7 12:28:53 2014  Nobuyoshi Nakada  <nobu@ruby-lang.org>
+
+	* ext/digest/digest.c (rb_digest_instance_equal): no need to call
+	  `to_s` twice.  [Bug #9913]
+
 Sat Jun  7 11:35:01 2014  Tanaka Akira  <akr@fsij.org>
 
 	* object.c (rb_mod_initialize_clone): Override Kernel#initialize_clone

ext/digest/digest.c

@@ -370,11 +370,10 @@ rb_digest_instance_equal(VALUE self, VALUE other)
     if (rb_obj_is_kind_of(other, rb_mDigest_Instance) == Qtrue) {
         str1 = rb_digest_instance_digest(0, 0, self);
         str2 = rb_digest_instance_digest(0, 0, other);
-    } else if (!NIL_P(rb_check_string_type(other))) {
-        str1 = rb_digest_instance_to_s(self);
-        str2 = other;
     } else {
-        return Qfalse;
+        str1 = rb_digest_instance_to_s(self);
+        str2 = rb_check_string_type(other);
+        if (NIL_P(str2)) return Qfalse;
     }
 
     /* never blindly assume that subclass methods return strings */