Currently the vectorizedMismatch intrinsic is in the toBeInvestigated list:

./share/classes/org.graalvm.compiler.hotspot.test/src/org/graalvm/compiler/hotspot/test/CheckGraalIntrinsics.java

There is a JMH micro for testing ArraysMismatch: open/test/micro/org/openjdk/bench/java/util/ArraysMismatch.java

Implementing this in the longest case would be a ~150% speedup.