[12] RFR(S): 8217230: assert(t == t_no_spec) failure in NodeHash::check_no_speculative_types()

[Tobias Hartmann]

Hi,

please review the following patch:
https://bugs.openjdk.java.net/browse/JDK-8217230
http://cr.openjdk.java.net/~thartmann/8217230/webrev.00/

A SafePointNode becomes dead when being cut off from root in Compile::remove_root_to_sfpts_edges()
but is not processed by IGVN and therefore remains in the graph. Since it is not reachable by root
anymore, it is not processed by Compile::remove_speculative_types and we hit the assert.

The problem was introduced by the fix for JDK-8214862 [1] in JDK 12 b27.

Thanks,
Tobias

[1] https://bugs.openjdk.java.net/browse/JDK-8214862