RFR: 8257221: C2: RegMask::is_bound_set split set handling broken since JDK-8221404 [v3]

[Nils Eliasson]

On Mon, 30 Nov 2020 07:06:10 GMT, Claes Redestad <redestad at openjdk.org> wrote:

>> This patch adds more tests for RegMask::is_bound* operations, and fixes a bug I introduced in JDK-8221404 where I mixed up the formula for how much we need to shift the "bit" when checking a split set.
>
> Claes Redestad has updated the pull request with a new target base due to a merge or a rebase. The incremental webrev excludes the unrelated changes brought in by the merge/rebase. The pull request contains eight additional commits since the last revision:
> 
>  - Merge branch 'master' into regmask_bound
>  - Clean-up is_bound_set test
>  - Split out the optimization
>  - Add is_bound_set test, fix bug caused by 8221404
>  - Add is_bound_pair test, remove redundant test in else branch, fix accidentally 32-bit uint bit
>  - Merge branch 'master' into regmask_bound
>  - Merge branch 'master' into regmask_bound
>  - C2: Optimize is_bound

Looks good.

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Marked as reviewed by neliasso (Reviewer).

PR: https://git.openjdk.java.net/jdk/pull/1486