RFR: 8295066: Folding of loads is broken in C2 after JDK-8242115

[Vladimir Kozlov]

On Tue, 25 Oct 2022 19:50:10 GMT, Igor Veresov <iveresov at openjdk.org> wrote:

> The fix does two things:
> 
> 1. Allow folding of pinned loads to constants with a straight line data flow (no phis).
> 2. Make scalarization aware of the new shape of the barriers so that pre-loads can be ignored.
> 
> Testing is clean, Valhalla testing is clean too.

Looks good.
Please, test full first 3 tier1-3 (not just hs-tier*).

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Marked as reviewed by kvn (Reviewer).

PR: https://git.openjdk.org/jdk/pull/10861