RFR: 8315066: Add unsigned bounds and known bits to TypeInt/Long [v39]

[Quan Anh Mai]

On Thu, 30 Jan 2025 12:52:16 GMT, Emanuel Peter <epeter at openjdk.org> wrote:

>> Quan Anh Mai has updated the pull request incrementally with one additional commit since the last revision:
>> 
>>   include
>
> src/hotspot/share/opto/rangeinference.cpp line 59:
> 
>> 57: // This class deals with each interval with both bounds being >= 0 or < 0 in
>> 58: // the signed domain. We call it Simple because a canonicalized TypeIntPrototype
>> 59: // may contain 1 or 2 SimpleCanonicalResult.
> 
> Aha! Now I understand why "Simple"!
> It could be nice if you had a constructor where you validate the "simple" constraint, i.e. that we are in either of these cases:
> - empty.
> - `[lo, hi] >= 0` and `[lo, hi] == [ulo, uhi]`
> - `[lo, hi] < 0` and `[ulo, uhi] >= 2^31` and `[lo, hi] = [(jint)ulo, (jint)uhi]`
> I did understand this correctly, right?

Defining a constructor prevents usage of brace initialization :(

> src/hotspot/share/opto/rangeinference.cpp line 66:
> 
>> 64:   bool _present; // whether this is an empty set
>> 65:   RangeInt<U> _bounds;
>> 66:   KnownBits<U> _bits;
> 
> Could these be const? That would additionally guaratee that nobody can come in and violate the "simple" constraint.

Making a member const would make the whole object kind of const, which is not ideal here.

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PR Review Comment: https://git.openjdk.org/jdk/pull/17508#discussion_r1935767997
PR Review Comment: https://git.openjdk.org/jdk/pull/17508#discussion_r1935769385