diff --git a/ChangeLog b/ChangeLog
index 782578a..99f2561 100644
--- a/ChangeLog
+++ b/ChangeLog
@@ -1,3 +1,9 @@
+2005-02-10  Ben Elliston  <bje@gnu.org>
+
+	* config.guess (amd64:CYGWIN*:*:*): New.
+	* testsuite/config-sub.data: Add amd64-cygwin, x86_64-cygwin.
+	* testsuite/config-guess.data: Add x86_64-unknown-cygwin test.
+
 2005-02-10  Ben Elliston  <bje@gnu.org>
 
 	* config.guess: Update copyright years.
diff --git a/config.guess b/config.guess
index 414548e..1a2262e 100755
--- a/config.guess
+++ b/config.guess
@@ -804,6 +804,9 @@ EOF
     i*:UWIN*:*)
 	echo ${UNAME_MACHINE}-pc-uwin
 	exit 0 ;;
+    amd64:CYGWIN*:*:*)
+	echo x86_64-unknown-cygwin
+	exit 0 ;;
     p*:CYGWIN*:*)
 	echo powerpcle-unknown-cygwin
 	exit 0 ;;
diff --git a/testsuite/config-guess.data b/testsuite/config-guess.data
index 2c20a5c..d9b2e05 100644
--- a/testsuite/config-guess.data
+++ b/testsuite/config-guess.data
@@ -1,5 +1,5 @@
-i386	1.6		NetBSD	GENERIC	i386-unknown-netbsdelf1.6
-crisv32	2.6.6		Linux	ignored	crisv32-axis-linux-gnu
-frv	2.4.24		Linux	ignored	frv-unknown-linux-gnu
-3	2.3.3		XENIX	SysV	i386-pc-xenix
-2064	ignored		z/VM	ignored	s390-ibm-zvmoe
+crisv32	2.6.6			Linux		ignored	crisv32-axis-linux-gnu
+frv	2.4.24			Linux		ignored	frv-unknown-linux-gnu
+3	2.3.3			XENIX		SysV	i386-pc-xenix
+2064	ignored			z/VM		ignored	s390-ibm-zvmoe
+amd64	1.5.12(0.116/4/2)	CYGWIN_NT-5.2	ignored	x86_64-unknown-cygwin
diff --git a/testsuite/config-sub.data b/testsuite/config-sub.data
index 88f32bc..10f6521 100644
--- a/testsuite/config-sub.data
+++ b/testsuite/config-sub.data
@@ -28,3 +28,5 @@ xscaleel			xscaleel-unknown-none
 xbox				i686-pc-mingw32
 maxq				maxq-unknown-none
 maxq-elf			maxq-unknown-elf
+amd64-cygwin			x86_64-pc-cygwin
+x86_64-cygwin			x86_64-pc-cygwin