[9] RFR(XS): 8086057: Crash with "modified node is not on IGVN._worklist" when running with -XX:-SplitIfBlocks

[Tobias Hartmann]

Hi,

please review the following patch:

https://bugs.openjdk.java.net/browse/JDK-8086057
http://cr.openjdk.java.net/~thartmann/8086057/webrev.00/

The fastdebug VM crashes with "modified node is not on IGVN._worklist" because SuperWord::align_initial_loop_index() resets the input of the pre-loop Opaque1 node 'pre_opaq' without putting it on the IGVN worklist afterwards. This only shows up with -XX:-SplitIfBlocks because otherwise surrounding nodes are changed causing the OpagueNode to be put on the worklist. The method should use PhaseIterGVN::replace_input_of() which uses rehash_node_delayed() to ensure the modified node is put on the worklist.

Tested with regression test, Nashorn+Octane with -XX:-SplitIfBlocks and RBT (running).

Thanks,
Tobias