--- old/src/jdk.internal.vm.compiler/share/classes/org.graalvm.compiler.lir.aarch64/src/org/graalvm/compiler/lir/aarch64/AArch64PrefetchOp.java	2017-07-07 09:30:35.000000000 -0700
+++ new/src/jdk.internal.vm.compiler/share/classes/org.graalvm.compiler.lir.aarch64/src/org/graalvm/compiler/lir/aarch64/AArch64PrefetchOp.java	2017-07-07 09:30:34.000000000 -0700
@@ -25,6 +25,7 @@
 
 import static org.graalvm.compiler.lir.LIRInstruction.OperandFlag.COMPOSITE;
 
+import org.graalvm.compiler.asm.aarch64.AArch64Assembler.PrefetchMode;
 import org.graalvm.compiler.asm.aarch64.AArch64MacroAssembler;
 import org.graalvm.compiler.lir.LIRInstructionClass;
 import org.graalvm.compiler.lir.asm.CompilationResultBuilder;
@@ -32,18 +33,18 @@
 public final class AArch64PrefetchOp extends AArch64LIRInstruction {
     public static final LIRInstructionClass<AArch64PrefetchOp> TYPE = LIRInstructionClass.create(AArch64PrefetchOp.class);
 
-    @SuppressWarnings("unused") private final int instr;  // AllocatePrefetchInstr
+    private final PrefetchMode mode;  // AllocatePrefetchInstr
     @Alive({COMPOSITE}) protected AArch64AddressValue address;
 
-    public AArch64PrefetchOp(AArch64AddressValue address, int instr) {
+    public AArch64PrefetchOp(AArch64AddressValue address, PrefetchMode mode) {
         super(TYPE);
         this.address = address;
-        this.instr = instr;
+        this.mode = mode;
     }
 
     @Override
     public void emitCode(CompilationResultBuilder crb, AArch64MacroAssembler masm) {
-        // TODO implement prefetch
-        masm.nop();
+        // instr gets ignored!
+        masm.prfm(address.toAddress(), mode);
     }
 }