RFR: 8324752: C2 Superword: remove SuperWordRTDepCheck

[Vladimir Kozlov]

On Fri, 26 Jan 2024 10:11:29 GMT, Emanuel Peter <epeter at openjdk.org> wrote:

> Subtask of https://github.com/openjdk/jdk/pull/16620
> 
> SuperWordRTDepCheck is a debug-only flag, which detects if there are arrays in the same slice that have different bases, i.e. may be different arrays. This could be the basis for alias-analysis.
> 
> We should do aliasing-analysis properly in a future RFE ([JDK-8324751](https://bugs.openjdk.org/browse/JDK-8324751)). If we can prove (statically or with a runtime-check) that two arrays are different, then this removes edges from the dependency graph, and may allow vectorization that would otherwise not be possible.

I did not even know we had such code.
I agree that we should do proper analysis instead of this experimental code (which is off by default and can't be switched on in product).

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Marked as reviewed by kvn (Reviewer).

PR Review: https://git.openjdk.org/jdk/pull/17585#pullrequestreview-1846227740