RFR: 8287794: Reverse*VNode::Identity problem [v2]

[Xiaohong Gong]

On Mon, 25 Jul 2022 05:24:34 GMT, Jatin Bhateja <jbhateja at openjdk.org> wrote:

>> test/hotspot/jtreg/compiler/vectorapi/TestReverseByteTransforms.java line 99:
>> 
>>> 97: 
>>> 98:     @Test
>>> 99:     @IR(applyIfCPUFeatureOr={"sve", "true", "simd", "true", "avx2", "true"}, counts = {"ReverseBytesV" , " > 0 "})
>> 
>> After https://github.com/openjdk/jdk/pull/9509 merged, I think we'd better to consider different vm flags like "UseAVX", "UseSVE" for each architecture. For example, if the cpu feature mathes "sve", but user may set "-XX:UseSVE=0". With such options, this IR test will also run and I'm afraid it will fail with "-XX:UseSVE=0".
>
> CPU features list is populated during VM startup, this list is later ON queried by applyIfCPUFeature during IR validations, I do not think UseSVE is a valid flag for X86, 
> 
> 
> SPROMPT>java -XX:UseSVE=0
> Unrecognized VM option 'UseSVE=0'
> Error: Could not create the Java Virtual Machine.
> Error: A fatal exception has occurred. Program will exit.
> SPROMPT>lscpu
> Architecture:                    x86_64
> CPU op-mode(s):                  32-bit, 64-bit
> Byte Order:                      Little Endian
> Address sizes:                   46 bits physical, 48 bits virtual
> CPU(s):                          72
> On-line CPU(s) list:             0-71
> Thread(s) per core:              2
> Core(s) per socket:              18
> Socket(s):                       2
> NUMA node(s):                    2
> Vendor ID:                       GenuineIntel
> CPU family:                      6
> Model:                           85
> Model name:                      Intel(R) Xeon(R) Gold 6139 CPU @ 2.30GHz

Yes, it's invalid on x86. So maybe you could add the limitation to the "requires", but seems this could make the codes complex.

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PR: https://git.openjdk.org/jdk/pull/9623