--- old/src/cpu/x86/vm/x86_64.ad	2011-07-22 11:55:12.446184011 +0200
+++ new/src/cpu/x86/vm/x86_64.ad	2011-07-22 11:55:12.231393843 +0200
@@ -7376,8 +7376,7 @@
 
 instruct membar_acquire_lock()
 %{
-  match(MemBarAcquire);
-  predicate(Matcher::prior_fast_lock(n));
+  match(MemBarAcquireLock);
   ins_cost(0);
 
   size(0);
@@ -7399,8 +7398,7 @@
 
 instruct membar_release_lock()
 %{
-  match(MemBarRelease);
-  predicate(Matcher::post_fast_unlock(n));
+  match(MemBarReleaseLock);
   ins_cost(0);
 
   size(0);