http://cr.openjdk.java.net/~iklam/valhalla/8219242-aastore-phi-node-needs-flat-check.v01/ https://bugs.openjdk.java.net/browse/JDK-8219242 With this fix, all current C1 compiler test cases have passed :-) My plan is to now enable the other tests that have been disabled for C1, and keep going .... Thanks - Ioi