RFR: 8319822: Use a linear-time algorithm for assert_different_registers() [v12]

[Andrew Haley]

On Mon, 3 Jun 2024 09:10:15 GMT, Thomas Stuefe <stuefe at openjdk.org> wrote:

>> Andrew Haley has updated the pull request with a new target base due to a merge or a rebase. The incremental webrev excludes the unrelated changes brought in by the merge/rebase. The pull request contains 19 additional commits since the last revision:
>> 
>>  - Merge branch 'clean' into different-regs
>>  - Review feedback
>>  - Review feedback
>>  - Update src/hotspot/share/asm/register.hpp
>>    
>>    Co-authored-by: Stefan Karlsson <stefan.karlsson at oracle.com>
>>  - Review feedback
>>  - Review feedback
>>  - Review feedback
>>  - Merge branch 'different-regs' of https://github.com/theRealAph/jdk into different-regs
>>  - Update src/hotspot/share/asm/register.hpp
>>    
>>    Co-authored-by: Emanuel Peter <emanuel.peter at oracle.com>
>>  - Merge branch 'clean' into different-regs
>>  - ... and 9 more: https://git.openjdk.org/jdk/compare/55c9e523...c9fc63d7
>
> src/hotspot/share/asm/register.hpp line 109:
> 
>> 107: 
>> 108:   constexpr AbstractRegSet(RegImpl r1)
>> 109:     : _bitset(r1->is_valid() ? size_t(1) << r1->encoding() : 0) { }
> 
> If my assumption from above is correct, we never noticed ppc being broken since _bitset would have been 0 if encoding > 31.
> 
> Could you add something like:
> 
> 
> STATIC_ASSERT(RegImpl::number_of_registers <= 64);
> 
> 
> ?

OK.

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PR Review Comment: https://git.openjdk.org/jdk/pull/16617#discussion_r1624426065