RFR: 8286800: Assert in PhaseIdealLoop::dump_real_LCA is too strong

[Dhamoder Nalla]

On Wed, 28 Sep 2022 19:04:07 GMT, Dhamoder Nalla <duke at openjdk.org> wrote:

> https://bugs.openjdk.org/browse/JDK-8286800
> 
> assert(real_LCA != NULL) in dump_real_LCA is not appropriate in bad graph scenario when both wrong_lca & early nodes are start nodes
> 
> jvm!PhaseIdealLoop::dump_real_LCA():
> // Walk the idom chain up from early and wrong_lca and stop when they intersect.
> while (!n1->is_Start() && !n2->is_Start()) {
> ...
> }
> assert(real_LCA != NULL, "must always find an LCA");
> 
> Fix: replace assert with a console message

> 

Thanks @chhagedorn, please take this over as you are already familiar with this area.

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PR: https://git.openjdk.org/jdk/pull/10472