[v9_8] check for physical equivalence in names

3599.	[tuning]	Check for pointer equivalence in name comparisons.
			[RT #18125]
(cherry picked from commit 7c2f548141)

CHANGES

@@ -1,3 +1,6 @@
+3599.	[tuning]	Check for pointer equivalence in name comparisons.
+			[RT #18125]
+
 3594.	[maint]		Update config.guess and config.sub. [RT #33816]
 
 3592.	[doc]		Moved documentation of rndc command options to the

lib/dns/name.c

@@ -578,6 +578,11 @@ dns_name_fullcompare(const dns_name_t *name1, const dns_name_t *name2,
 	REQUIRE((name1->attributes & DNS_NAMEATTR_ABSOLUTE) ==
 		(name2->attributes & DNS_NAMEATTR_ABSOLUTE));
 
+	if (name1 == name2) {
+		*orderp = 0;
+		return (dns_namereln_equal);
+	}
+
 	SETUP_OFFSETS(name1, offsets1, odata1);
 	SETUP_OFFSETS(name2, offsets2, odata2);
 
@@ -691,6 +696,9 @@ dns_name_equal(const dns_name_t *name1, const dns_name_t *name2) {
 	REQUIRE((name1->attributes & DNS_NAMEATTR_ABSOLUTE) ==
 		(name2->attributes & DNS_NAMEATTR_ABSOLUTE));
 
+	if (name1 == name2)
+		return (ISC_TRUE);
+
 	if (name1->length != name2->length)
 		return (ISC_FALSE);