RFR: 8315066: Add unsigned bounds and known bits to TypeInt/Long [v7]

[Quan Anh Mai]

On Tue, 3 Sep 2024 14:05:36 GMT, Emanuel Peter <epeter at openjdk.org> wrote:

>> Quan Anh Mai has updated the pull request with a new target base due to a merge or a rebase. The pull request now contains 11 commits:
>> 
>>  - fix compile errors
>>  - Merge branch 'master' into unsignedbounds
>>  - add comments
>>  - Merge branch 'master' into unsignedbounds
>>  - fix release build
>>  - add comments, group arguments to reduce C-style reference passing arguments
>>  - fix tests, add verify
>>  - add unit tests
>>  - fix template parameter
>>  - refactor
>>  - ... and 1 more: https://git.openjdk.org/jdk/compare/d8e4d3f2...d5ad9f1a
>
> src/hotspot/share/opto/rangeinference.cpp line 113:
> 
>> 111:   T match_mask = mismatch == 0 ? std::numeric_limits<T>::max()
>> 112:                                : ~(std::numeric_limits<T>::max() >> count_leading_zeros(mismatch));
>> 113:   T new_zeros = bits._zeros | (match_mask &~ bounds._lo);
> 
> Suggestion:
> 
>   T new_zeros = bits._zeros | (match_mask & ~bounds._lo);
> 
> I think this was a typo?

It looks more like an `and not` to me :) However, if you prefer the `~` to stick to `bounds._lo` I would make that change.

> test/hotspot/gtest/opto/test_rangeinference.cpp line 148:
> 
>> 146:   test_normalize_constraints_random<jint, juint>();
>> 147:   test_normalize_constraints_random<jlong, julong>();
>> 148: }
> 
> I would appreciate it if there were some explicit examples with explicit result verification. Just to make sure the methods are not systematically wrong in some silly way.

My idea is that it is what `test_normalize_constraints_simple` would do, but I think adding some more explicit cases would help, too.

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PR Review Comment: https://git.openjdk.org/jdk/pull/17508#discussion_r1742670148
PR Review Comment: https://git.openjdk.org/jdk/pull/17508#discussion_r1742668030