RFR: 8285793: C2: optimization of mask checks in counted loops fail in the presence of cast nodes

[Vladimir Kozlov]

On Thu, 28 Apr 2022 09:39:18 GMT, Roland Westrelin <roland at openjdk.org> wrote:

> This showed up when working with a panama micro benchmark. Optimization of:
> 
> if ((base + (offset << 2)) & 3) != 0) {
> }
> 
> into:
> 
> if ((base & 3) != 0) {
> 
> fails if the subgraph contains cast nodes.

Tobias already submitted testing.

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Marked as reviewed by kvn (Reviewer).

PR: https://git.openjdk.java.net/jdk/pull/8447