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

[Jie Fu]

On Mon, 14 Dec 2020 16:07:48 GMT, Nils Eliasson <neliasso 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 just follows what is done for x86_64.
>> 
>> 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
>
> Changes requested by neliasso (Reviewer).

The new pr is here: https://github.com/openjdk/jdk16/pull/21
Thanks.

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PR: https://git.openjdk.java.net/jdk/pull/1753