RFR: 8321122: Shenandoah: Remove ShenandoahLoopOptsAfterExpansion flag

[Aleksey Shipilev]

On Mon, 4 Dec 2023 14:13:56 GMT, Roland Westrelin <roland at openjdk.org> wrote:

> > I think long-term we want to switch to late barrier insertion anyway, which would render this flag obsolete.
> 
> They seem to be different things to me. Having the ability to optimize the barrier after it's expanded or inserted seems like a useful thing to have in any case. Is there evidence that late barrier insertion would solve existing issues?

I thought late barrier insertion basically avoids dealing with any optimizer questions, as we insert the barriers close to emit. So if we are to do late barrier insertion, we don't need the bulk of barrier optimization code? Maybe I misunderstand where late barrier insertion fits in C2.

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PR Comment: https://git.openjdk.org/jdk/pull/16908#issuecomment-1838919728