Integrated: 8372451: C2 SuperWord: "endless loop" assert. Need to implement proper worklist mechanism

[Emanuel Peter]

On Wed, 26 Nov 2025 16:02:20 GMT, Emanuel Peter <epeter at openjdk.org> wrote:

> **Context**: `VTransform::optimize`. Works a bit like IGVN, it allows each node to perform optimizations. Recently introduced during JDK26.
> 
> **Problem**: I made the assumption that we don't need a worklist mechanism, we can just do multiple passes over all nodes. The assumption was that there would not be any "trickling" of updates over the graph. But that is wrong: for example we can have a long chain of dead nodes, and we need to progressively remove the last node and mark it as dead.
> 
> **Solution**: Implement proper worklist mechanism, so that updates can trickle over the graph.

This pull request has now been integrated.

Changeset: 6c01d3b0
Author:    Emanuel Peter <epeter at openjdk.org>
URL:       https://git.openjdk.org/jdk/commit/6c01d3b08862447983b96daaf34a4c62daf54101
Stats:     208 lines in 3 files changed: 164 ins; 1 del; 43 mod

8372451: C2 SuperWord: "endless loop" assert. Need to implement proper worklist mechanism

Reviewed-by: mhaessig, chagedorn

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PR: https://git.openjdk.org/jdk/pull/28512