[9] RFR(S): 8155643: Java crash with assert in Xcomp mode and disabled ReduceInitialCardMarks

[Tobias Hartmann]

Hi,

please review the following patch:

https://bugs.openjdk.java.net/browse/JDK-8155643
http://cr.openjdk.java.net/~thartmann/8155643/webrev.00/

We hit the "should have klasses" assert in PhaseMacroExpand::generate_arraycopy() while intrinsifying Object[].clone() because the src and dst klass is not set. This is because if ReduceInitialCardMarks is disabled, we emit a copy of type 'CloneOop' instead of a 'CloneBasic'. In both cases we should not emit a subtype check.

Tested on JPRT and RBT (running).

Thanks,
Tobias