RFR: 8291649: multiple tests failing with -Xcomp after JDK-8290034 [v3]

[John R Rose]

On Fri, 26 Aug 2022 13:42:16 GMT, Jatin Bhateja <jbhateja at openjdk.org> wrote:

>> Hi,
>> 
>> This bug fix patch fixes the incorrect computation during constant folding of Reverse[IL] IR node.
>> A new utility class has been added to optimize computation of reverse_bit operation using GCC built-ins.
>> 
>> Kindly review and share your feedback.
>> 
>> Best Regards,
>> Jatin
>
> Jatin Bhateja has updated the pull request incrementally with one additional commit since the last revision:
> 
>   8291649: Incorporating code changes from Kim and John.

I recommend using Kim's version; I decided I like his metaprogramming trick that creates the type `I` to precisely capture the details of C++ "usual integral promotions".  The type of the `rep_XXX` constants should be `I` not `T` or `uint64_t`.

See comment above about a helpful comment in the gtest file, so folks can readily make sure that the `bswap` instructions are used by the C++ compiler.

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Marked as reviewed by jrose (Reviewer).

PR: https://git.openjdk.org/jdk/pull/9987