[jdk16] Integrated: 8259641: C2: assert(early->dominates(LCA)) failed: early is high enough

[Roland Westrelin]

On Thu, 14 Jan 2021 08:05:25 GMT, Roland Westrelin <roland at openjdk.org> wrote:

> For the fix of 8258393 that causes this regression, I wrote that the
> goal was:
> 
> "I propose to be less conservative in anti-dependence analysis for
> Phis. For a Phi, when computing the LCA, I think it's sufficient to
> only consider region's inputs that we actually reach by following the
> memory edges and that's what I propose here."
> 
> But that's not what the logic I added does. It checks whether a Phi
> input should be taken into account by checking whether it's in the
> worklist but the worklist doesn't include mem, the memory state from
> which we started.

This pull request has now been integrated.

Changeset: d5ca3b3f
Author:    Roland Westrelin <roland at openjdk.org>
URL:       https://git.openjdk.java.net/jdk16/commit/d5ca3b3f
Stats:     96 lines in 2 files changed: 95 ins; 0 del; 1 mod

8259641: C2: assert(early->dominates(LCA)) failed: early is high enough

Reviewed-by: chagedorn, thartmann

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PR: https://git.openjdk.java.net/jdk16/pull/121