[jdk16] RFR: 8258134: assert(size == calc_size) failed: incorrect size calculation on x86_32 with AVX512 machines

[Jie Fu]

On Fri, 18 Dec 2020 10:04:15 GMT, Tobias Hartmann <thartmann at openjdk.org> wrote:

>> Hi all,
>> 
>> Two vector api tests crashed on x86_32 with AVX512 machines due to this assert [1].
>> The reason is that 'calc_size' is incorrect.
>> 
>> But there is no need to calculate 'calc_size' manually at all since the result [2] is actually never used by the VM.
>> Also, it is really hard to maintain the calculation logic for various hardwares and configurations.
>> And it may be easily broken again in the future with more and more complicated instructions & configurations.
>> 
>> So it would be better to remove the calculation and the assert, which is safe and already done for x86_64 [3].
>> The fix follows what is done for x86_64.
>> And it also makes vec_stack_to_stack_helper, vec_mov_helper and vec_spill_helper return void according to @neliasso 's comments [4].
>> 
>> Thanks.
>> Best regards,
>> Jie
>> 
>> [1] https://github.com/openjdk/jdk/blob/master/src/hotspot/cpu/x86/x86_32.ad#L1016
>> [2] https://github.com/openjdk/jdk/blob/master/src/hotspot/cpu/x86/x86_32.ad#L1059
>> [3] https://github.com/openjdk/jdk/blob/master/src/hotspot/cpu/x86/x86_64.ad#L1042
>> [4] https://github.com/openjdk/jdk/pull/1753#discussion_r542505836
>
> Looks good.

Thanks @TobiHartmann for your review.

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PR: https://git.openjdk.java.net/jdk16/pull/21