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

[Roland Westrelin]

On Fri, 29 Apr 2022 10:59:16 GMT, Tobias Hartmann <thartmann 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.
>
> Looks good. All tests passed.

@TobiHartmann @vnkozlov thanks for the reviews and testing

-------------

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