RFR: 8265132 : C2 compilation fails with assert "missing precedence edge" [v4]

[Dean Long]

On Thu, 27 May 2021 21:05:33 GMT, Jamsheed Mohammed C M <jcm at openjdk.org> wrote:

>> Issue is similar to https://bugs.openjdk.java.net/browse/JDK-8261730
>> but happens at next https://github.com/jamsheedcm/jdk/blob/master/src/hotspot/share/opto/gcm.cpp#L830
>> 
>> Request for review
>
> Jamsheed Mohammed C M has updated the pull request incrementally with one additional commit since the last revision:
> 
>   improving the fix for raise_LCA_above_marks

src/hotspot/share/opto/gcm.cpp line 816:

> 814:       assert(store != load->find_exact_control(load->in(0)), "dependence cycle found");
> 815:       if (verify) {
> 816:         assert(store->find_edge(load) != -1 || unrelated_load_in_store_null_block(store, load),

I'm probably missing something, but the new code doesn't look equivalent to the old code, unless the bug fix is part of the refactoring.  You removed the check against LCA and added a new dominates check.

-------------

PR: https://git.openjdk.java.net/jdk/pull/4200