--- src/backend/storage/lmgr/s_lock.c
+++ src/backend/storage/lmgr/s_lock.c
@@ -140,7 +140,7 @@
 }
 #endif   /* __APPLE__ && __ppc__ */
 
-#if defined(__powerpc__)
+#if defined(__powerpc__) && !defined(__powerpc64__)
 /* Note: need a nice gcc constrained asm version so it can be inlined */
 static void
 tas_dummy()
@@ -164,6 +164,30 @@
 }
 #endif   /* __powerpc__ */
 
+#if defined(__powerpc64__)
+/* Note: need a nice gcc constrained asm version so it can be inlined */
+static void
+tas_dummy()
+{
+	__asm__		__volatile__(
+										 "\
+.global .tas 					\n\
+.tas:							\n\
+			lwarx	5,0,3		\n\
+			cmpwi 	5,0 		\n\
+			bne 	fail		\n\
+			addi 	5,5,1		\n\
+			stwcx.	5,0,3		\n\
+			beq 	success 	\n\
+fail:		li		3,1 		\n\
+			blr 				\n\
+success:						\n\
+			li 		3,0			\n\
+			blr					\n\
+");
+}
+#endif   /* __powerpc64__ */
+
 #if defined(__mips__) && !defined(__sgi)
 static void
 tas_dummy()