diff --git a/src/frontend/A64/translate/impl/simd_three_same.cpp b/src/frontend/A64/translate/impl/simd_three_same.cpp
index ad27bbe4..15d93fe6 100644
--- a/src/frontend/A64/translate/impl/simd_three_same.cpp
+++ b/src/frontend/A64/translate/impl/simd_three_same.cpp
@@ -123,9 +123,12 @@ bool TranslatorVisitor::ORN_asimd(bool Q, Vec Vm, Vec Vn, Vec Vd) {
     auto operand1 = V(datasize, Vn);
     auto operand2 = V(datasize, Vm);
 
-    // TODO: This does not zero the upper 64 bits when datasize == 64. This may break future optimization passes.
     auto result = ir.VectorOr(operand1, ir.VectorNot(operand2));
 
+    if (datasize == 64) {
+        result = ir.VectorZeroUpper(result);
+    }
+
     V(datasize, Vd, result);
 
     return true;