--- a/jvmci/jdk.vm.ci.hotspot.amd64/src/jdk/vm/ci/hotspot/amd64/AMD64HotSpotRegisterConfig.java	Fri Jan 22 12:48:29 2016 -1000
+++ b/jvmci/jdk.vm.ci.hotspot.amd64/src/jdk/vm/ci/hotspot/amd64/AMD64HotSpotRegisterConfig.java	Fri Jan 22 12:48:57 2016 -1000
@@ -45,6 +45,7 @@
 import java.util.Arrays;
 import java.util.Collections;
 import java.util.HashSet;
+import java.util.List;
 import java.util.Set;
 
 import jdk.vm.ci.code.Architecture;
@@ -119,14 +120,17 @@
      */
     private final boolean needsNativeStackHomeSpace;
 
+    private static final Register[] reservedRegisters = {rsp, r15};
+
     private static Register[] initAllocatable(Architecture arch, boolean reserveForHeapBase) {
         Register[] allRegisters = arch.getAvailableValueRegisters();
-        Register[] registers = new Register[allRegisters.length - (reserveForHeapBase ? 3 : 2)];
+        Register[] registers = new Register[allRegisters.length - reservedRegisters.length - (reserveForHeapBase ? 1 : 0)];
+        List<Register> reservedRegistersList = Arrays.asList(reservedRegisters);
 
         int idx = 0;
         for (Register reg : allRegisters) {
-            if (reg.equals(rsp) || reg.equals(r15)) {
-                // skip stack pointer and thread register
+            if (reservedRegistersList.contains(reg)) {
+                // skip reserved registers
                 continue;
             }
             if (reserveForHeapBase && reg.equals(r12)) {