--- old/src/cpu/x86/vm/x86_32.ad	2011-07-11 12:15:12.945375523 +0200
+++ new/src/cpu/x86/vm/x86_32.ad	2011-07-11 12:15:12.478233782 +0200
@@ -7805,17 +7805,6 @@
   ins_pipe(empty);
 %}
 
-instruct membar_acquire_lock() %{
-  match(MemBarAcquire);
-  predicate(Matcher::prior_fast_lock(n));
-  ins_cost(0);
-
-  size(0);
-  format %{ "MEMBAR-acquire (prior CMPXCHG in FastLock so empty encoding)" %}
-  ins_encode( );
-  ins_pipe(empty);
-%}
-
 instruct membar_release() %{
   match(MemBarRelease);
   ins_cost(400);
@@ -7825,17 +7814,6 @@
   ins_encode( );
   ins_pipe(empty);
 %}
-
-instruct membar_release_lock() %{
-  match(MemBarRelease);
-  predicate(Matcher::post_fast_unlock(n));
-  ins_cost(0);
-
-  size(0);
-  format %{ "MEMBAR-release (a FastUnlock follows so empty encoding)" %}
-  ins_encode( );
-  ins_pipe(empty);
-%}
 
 instruct membar_volatile(eFlagsReg cr) %{
   match(MemBarVolatile);