Integrated: 8263577: C2: reachable nodes shouldn't have dead uses at the end of optimizations

[Roland Westrelin]

On Mon, 15 Mar 2021 12:33:19 GMT, Roland Westrelin <roland at openjdk.org> wrote:

> It's not uncommon for c2 to leave dead uses hanging from reachable
> nodes. It's usually harmless but can cause confusion (such as in
> valhalla JDK-8262289, not reproducible with non valhalla code AFAICT).
> 
> Most of the time, these are caused by calls to set_req() during igvn
> that should be set_req_X() calls. I added a verification pass at the
> end of optimization and fixed all the ones I found.

This pull request has now been integrated.

Changeset: 20297a1b
Author:    Roland Westrelin <roland at openjdk.org>
URL:       https://git.openjdk.java.net/jdk/commit/20297a1b
Stats:     162 lines in 21 files changed: 61 ins; 42 del; 59 mod

8263577: C2: reachable nodes shouldn't have dead uses at the end of optimizations

Reviewed-by: vlivanov, neliasso

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PR: https://git.openjdk.java.net/jdk/pull/3012