--- old/src/cpu/x86/vm/x86_64.ad	Tue Aug 16 10:00:31 2011
+++ new/src/cpu/x86/vm/x86_64.ad	Tue Aug 16 10:00:31 2011
@@ -6617,8 +6617,9 @@
   ins_cost(125);
 
   format %{ "PREFETCHR $mem\t# Prefetch into level 1 cache" %}
-  opcode(0x0F, 0x0D);     /* Opcode 0F 0D /0 */
-  ins_encode(REX_mem(mem), OpcP, OpcS, RM_opc_mem(0x00, mem));
+  ins_encode %{
+    __ prefetchr($mem$$Address);
+  %}
   ins_pipe(ialu_mem);
 %}
 
@@ -6628,8 +6629,9 @@
   ins_cost(125);
 
   format %{ "PREFETCHNTA $mem\t# Prefetch into non-temporal cache for read" %}
-  opcode(0x0F, 0x18);     /* Opcode 0F 18 /0 */
-  ins_encode(REX_mem(mem), OpcP, OpcS, RM_opc_mem(0x00, mem));
+  ins_encode %{
+    __ prefetchnta($mem$$Address);
+  %}
   ins_pipe(ialu_mem);
 %}
 
@@ -6639,8 +6641,9 @@
   ins_cost(125);
 
   format %{ "PREFETCHT0 $mem\t# prefetch into L1 and L2 caches for read" %}
-  opcode(0x0F, 0x18); /* Opcode 0F 18 /1 */
-  ins_encode(REX_mem(mem), OpcP, OpcS, RM_opc_mem(0x01, mem));
+  ins_encode %{
+    __ prefetcht0($mem$$Address);
+  %}
   ins_pipe(ialu_mem);
 %}
 
@@ -6650,52 +6653,70 @@
   ins_cost(125);
 
   format %{ "PREFETCHT2 $mem\t# prefetch into L2 caches for read" %}
-  opcode(0x0F, 0x18); /* Opcode 0F 18 /3 */
-  ins_encode(REX_mem(mem), OpcP, OpcS, RM_opc_mem(0x03, mem));
+  ins_encode %{
+    __ prefetcht2($mem$$Address);
+  %}
   ins_pipe(ialu_mem);
 %}
 
-instruct prefetchw( memory mem ) %{
-  predicate(AllocatePrefetchInstr==3);
+instruct prefetchwNTA( memory mem ) %{
   match(PrefetchWrite mem);
   ins_cost(125);
 
-  format %{ "PREFETCHW $mem\t# Prefetch into level 1 cache and mark modified" %}
-  opcode(0x0F, 0x0D);     /* Opcode 0F 0D /1 */
-  ins_encode(REX_mem(mem), OpcP, OpcS, RM_opc_mem(0x01, mem));
+  format %{ "PREFETCHNTA $mem\t# Prefetch to non-temporal cache for write" %}
+  ins_encode %{
+    __ prefetchnta($mem$$Address);
+  %}
   ins_pipe(ialu_mem);
 %}
 
-instruct prefetchwNTA( memory mem ) %{
+// Prefetch instructions for allocation.
+
+instruct prefetchAlloc( memory mem ) %{
+  predicate(AllocatePrefetchInstr==3);
+  match(PrefetchAllocation mem);
+  ins_cost(125);
+
+  format %{ "PREFETCHW $mem\t# Prefetch allocation into level 1 cache and mark modified" %}
+  ins_encode %{
+    __ prefetchw($mem$$Address);
+  %}
+  ins_pipe(ialu_mem);
+%}
+
+instruct prefetchAllocNTA( memory mem ) %{
   predicate(AllocatePrefetchInstr==0);
-  match(PrefetchWrite mem);
+  match(PrefetchAllocation mem);
   ins_cost(125);
 
-  format %{ "PREFETCHNTA $mem\t# Prefetch to non-temporal cache for write" %}
-  opcode(0x0F, 0x18);     /* Opcode 0F 18 /0 */
-  ins_encode(REX_mem(mem), OpcP, OpcS, RM_opc_mem(0x00, mem));
+  format %{ "PREFETCHNTA $mem\t# Prefetch allocation to non-temporal cache for write" %}
+  ins_encode %{
+    __ prefetchnta($mem$$Address);
+  %}
   ins_pipe(ialu_mem);
 %}
 
-instruct prefetchwT0( memory mem ) %{
+instruct prefetchAllocT0( memory mem ) %{
   predicate(AllocatePrefetchInstr==1);
-  match(PrefetchWrite mem);
+  match(PrefetchAllocation mem);
   ins_cost(125);
 
-  format %{ "PREFETCHT0 $mem\t# Prefetch to level 1 and 2 caches for write" %}
-  opcode(0x0F, 0x18);     /* Opcode 0F 18 /1 */
-  ins_encode(REX_mem(mem), OpcP, OpcS, RM_opc_mem(0x01, mem));
+  format %{ "PREFETCHT0 $mem\t# Prefetch allocation to level 1 and 2 caches for write" %}
+  ins_encode %{
+    __ prefetcht0($mem$$Address);
+  %}
   ins_pipe(ialu_mem);
 %}
 
-instruct prefetchwT2( memory mem ) %{
+instruct prefetchAllocT2( memory mem ) %{
   predicate(AllocatePrefetchInstr==2);
-  match(PrefetchWrite mem);
+  match(PrefetchAllocation mem);
   ins_cost(125);
 
-  format %{ "PREFETCHT2 $mem\t# Prefetch to level 2 cache for write" %}
-  opcode(0x0F, 0x18);     /* Opcode 0F 18 /3 */
-  ins_encode(REX_mem(mem), OpcP, OpcS, RM_opc_mem(0x03, mem));
+  format %{ "PREFETCHT2 $mem\t# Prefetch allocation to level 2 cache for write" %}
+  ins_encode %{
+    __ prefetcht2($mem$$Address);
+  %}
   ins_pipe(ialu_mem);
 %}