RFR: 8346916: [REDO] align_up has potential overflow [v9]

[Casper Norrbin]

On Tue, 11 Mar 2025 09:14:35 GMT, Albert Mingkun Yang <ayang at openjdk.org> wrote:

>> Casper Norrbin has updated the pull request incrementally with one additional commit since the last revision:
>> 
>>   removed template paramter and moved ptr can_align_up
>
> src/hotspot/share/utilities/align.hpp line 83:
> 
>> 81: constexpr T align_up(T size, A alignment) {
>> 82:   T mask = checked_cast<T>(alignment_mask(alignment));
>> 83:   assert(size <= std::numeric_limits<T>::max() - mask, "overflow");
> 
> Just curious, if `can_align_up` is precondition, why not `assert(can_align_up(...), "precondition")`? Then, the comment can even be dropped.

That is probably a cleaner way to do it now that we have `can_align_up`. I swapped the assert, and changed the rest of the function to look like before.

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PR Review Comment: https://git.openjdk.org/jdk/pull/23711#discussion_r1989615709