RFR: 8287794: Reverse*VNode::Identity problem

[Xiaohong Gong]

On Sat, 23 Jul 2022 17:39:27 GMT, Jatin Bhateja <jbhateja at openjdk.org> wrote:

> Hi All,
> 
> - This bug fix patch fixes a missing case during reverse[bits|bytes] identity transformation.
> - Unlike AARCH64(SVE), X86(AVX512) ISA has no direct instruction to reverse[bits|bytes] of a vector lane hence a predicated operation is supported through blend instruction.
> - New IR framework based tests has been added to test transforms relevant to AVX2, AVX512 and SVE.
> 
> Kindly review and share your feedback.
> 
> Best Regards,
> Jatin

test/hotspot/jtreg/compiler/vectorapi/TestReverseByteTransforms.java line 80:

> 78: 
> 79:     @Test
> 80:     @IR(applyIfCPUFeature={"sve", "true"}, failOn = {"ReverseBytesV" , " > 0 "})

Use " failOn = "ReverseBytesV" " instead?

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".

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