src/jdk.internal.vm.compiler/share/classes/org.graalvm.compiler.core.aarch64/src/org/graalvm/compiler/core/aarch64/AArch64ArithmeticLIRGenerator.java

@@ -60,15 +60,30 @@
 import jdk.vm.ci.meta.Value;
 import jdk.vm.ci.meta.ValueKind;
 
 public class AArch64ArithmeticLIRGenerator extends ArithmeticLIRGenerator implements AArch64ArithmeticLIRGeneratorTool {
 
+    public AArch64ArithmeticLIRGenerator(AllocatableValue nullRegisterValue) {
+        this.nullRegisterValue = nullRegisterValue;
+    }
+
+    private final AllocatableValue nullRegisterValue;
+
     @Override
     public AArch64LIRGenerator getLIRGen() {
         return (AArch64LIRGenerator) super.getLIRGen();
     }
 
+    public boolean mustReplaceNullWithNullRegister(JavaConstant nullConstant) {
+        /* Uncompressed null pointers only */
+        return nullRegisterValue != null && JavaConstant.NULL_POINTER.equals(nullConstant);
+    }
+
+    public AllocatableValue getNullRegisterValue() {
+        return nullRegisterValue;
+    }
+
     @Override
     protected boolean isNumericInteger(PlatformKind kind) {
         return ((AArch64Kind) kind).isInteger();
     }
 

@@ -483,15 +498,10 @@
         AllocatableValue input = asAllocatable(inputVal);
         getLIRGen().append(new StoreOp(kind, storeAddress, input, state));
     }
 
     @Override
-    public void emitCompareOp(AArch64Kind cmpKind, Variable left, Value right) {
-        throw GraalError.unimplemented();
-    }
-
-    @Override
     public Value emitRound(Value value, RoundingMode mode) {
         AArch64ArithmeticOp op;
         switch (mode) {
             case NEAREST:
                 op = AArch64ArithmeticOp.FRINTN;