RFR: 8324734: Relax too-strict assert(VM_Version::supports_evex()) in Assembler::locate_operand() [v3]

[Roman Kennke]

On Mon, 29 Jan 2024 18:45:20 GMT, Roman Kennke <rkennke at openjdk.org> wrote:

>> Details see bug report. The gist is that HotSpot downgrades to UseAVX=2 on some processors, and reports supports_evex() == false, but the instruction decoder can still encounter EVEX instructions when (e.g.) hitting a SIGBUS in memset() - which does have EVEX instructions.
>> 
>> Testing:
>>  - [x] runtime/Unsafe/InternalErrorTest.java
>>  - [x] tier1
>
> Roman Kennke has updated the pull request incrementally with five additional commits since the last revision:
> 
>  - Fix intendation
>  - Update src/hotspot/share/runtime/abstract_vm_version.hpp
>    
>    Co-authored-by: Aleksey Shipilëv <shipilev at amazon.de>
>  - Update src/hotspot/share/runtime/abstract_vm_version.hpp
>    
>    Co-authored-by: Aleksey Shipilëv <shipilev at amazon.de>
>  - Update src/hotspot/cpu/x86/vm_version_x86.hpp
>    
>    Co-authored-by: Aleksey Shipilëv <shipilev at amazon.de>
>  - Update src/hotspot/cpu/x86/vm_version_x86.cpp
>    
>    Co-authored-by: Aleksey Shipilëv <shipilev at amazon.de>

Thanks, Vladimir and Aleksey!

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PR Comment: https://git.openjdk.org/jdk/pull/17590#issuecomment-1916570404