[code-reflection] RFR: Fix SSABraun bug and add SSA tests [v4]

[Paul Sandoz]

On Thu, 11 Sep 2025 18:22:43 GMT, Ruby Chen <duke at openjdk.org> wrote:

>> Fix a bug in SSABraun where, in `tryRemoveTrivialPhi()`, a phi stored in `same` that is later deleted in a recursive `tryRemoveTrivialPhi()` call is still returned despite being deleted. 
>> 
>> Add five tests to TestSSA: `deadCode(), ifelseLoopNested(), violaJones(), binarySearch(),` and `quicksort()`. `violaJones()` is inspired by the method `findFeaturesKernel` in HAT kernel ViolaJones, which is the bug first presented itself.
>
> Ruby Chen 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 seven additional commits since the last revision:
> 
>  - Merge branch 'openjdk:code-reflection' into inline
>  - Add one more test and change equals
>  - Replace deleted phi after recursive call
>  - Merge branch 'openjdk:code-reflection' into inline
>  - Merge branch 'openjdk:code-reflection' into inline
>  - Merge branch 'openjdk:code-reflection' into inline
>  - Fix SSABraun bug and add SSA tests

Well done. We can investigate and address the use of identity equality in another PR, if necessary.

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Marked as reviewed by psandoz (Lead).

PR Review: https://git.openjdk.org/babylon/pull/542#pullrequestreview-3213132021