On Tue, 20 Oct 2026 08:02:05 GMT, Eric Fang <[email protected]> wrote:

>> The expression `(A & B) ^ B` is algebraically equivalent to `~A & B`, which 
>> maps directly to the AArch64 `BIC` (bit clear) instruction.
>> 
>> Now the expression is lowered as two operations `AndV` and `XorV`, this 
>> patch adds C2 match rules to fold this pattern into a single `BIC` for both 
>> integral vectors and vector masks on AArch64 (NEON and SVE). JMH 
>> micro-benchmarks demonstrate a significant performance improvement.
>> 
>> On a Nvidia Grace (Neoverse-V2) machine with 128-bit SVE2:
>> <html xmlns:v="urn:schemas-microsoft-com:vml"
>> xmlns:o="urn:schemas-microsoft-com:office:office"
>> xmlns:x="urn:schemas-microsoft-com:office:excel"
>> xmlns="http://www.w3.org/TR/REC-html40";>
>> 
>> <head>
>> 
>> <meta name=ProgId content=Excel.Sheet>
>> <meta name=Generator content="Microsoft Excel 15">
>> <link id=Main-File rel=Main-File
>> href="file:////Users/erfang/Library/Group%20Containers/UBF8T346G9.Office/TemporaryItems/msohtmlclip/clip.htm">
>> <link rel=File-List
>> href="file:////Users/erfang/Library/Group%20Containers/UBF8T346G9.Office/TemporaryItems/msohtmlclip/clip_filelist.xml">
>> 
>> </head>
>> 
>> <body link="#467886" vlink="#96607D">
>> 
>> 
>> Benchmark | size | Unit | Before | Error | After | Error | Uplift
>> -- | -- | -- | -- | -- | -- | -- | --
>> LogicOperationsBenchmark.byteNotAnd | 1024 | ops/ms | 20769.0 | 49.6 | 
>> 52065.1 | 684.0 | 2.51
>> LogicOperationsBenchmark.intNotAnd | 1024 | ops/ms | 3576.6 | 0.4 | 7980.8 | 
>> 4.0 | 2.23
>> LogicOperationsBenchmark.longNotAnd | 1024 | ops/ms | 1699.1 | 0.6 | 3575.1 
>> | 0.6 | 2.10
>> LogicOperationsBenchmark.shortNotAnd | 1024 | ops/ms | 7986.0 | 3.4 | 
>> 20523.8 | 13.6 | 2.57
>> MaskLogicOperationsBenchmark.byteMaskNotAnd | 256 | ops/ms | 82165.6 | 70.1 
>> | 108802.4 | 169.4 | 1.32
>> MaskLogicOperationsBenchmark.byteMaskNotAnd | 512 | ops/ms | 42859.7 | 27.1 
>> | 59531.1 | 65.5 | 1.39
>> MaskLogicOperationsBenchmark.byteMaskNotAnd | 1024 | ops/ms | 21703.1 | 9.3 
>> | 31475.2 | 5.5 | 1.45
>> MaskLogicOperationsBenchmark.intMaskNotAnd | 256 | ops/ms | 15467.4 | 50.9 | 
>> 27138.2 | 76.1 | 1.75
>> MaskLogicOperationsBenchmark.intMaskNotAnd | 512 | ops/ms | 7951.4 | 14.9 | 
>> 13962.2 | 4.9 | 1.76
>> MaskLogicOperationsBenchmark.intMaskNotAnd | 1024 | ops/ms | 3988.2 | 4.1 | 
>> 6876.1 | 2.1 | 1.72
>> MaskLogicOperationsBenchmark.longMaskNotAnd | 256 | ops/ms | 7933.8 | 6.4 | 
>> 13933.2 | 6.6 | 1.76
>> MaskLogicOperationsBenchmark.longMaskNotAnd | 512 | ops/ms | 3977.9 | 4.0 | 
>> 6865.8 | 4.2 | 1.73
>> MaskLogicOperationsBenchmark.longMaskNotAnd | 1024 | ops/ms | 1992.7 | 1...
>
> Eric Fang has updated the pull request incrementally with one additional 
> commit since the last revision:
> 
>   Remove the unrelated files that were accidentally included

src/hotspot/share/opto/genericOpts.cpp line 25:

> 23:  */
> 24: 
> 25: #include "opto/genericOpts.hpp"

Most files in `opto` follow `flatcase`, so I would suggest this file named 
`genericsopts`.

src/hotspot/share/opto/genericOpts.cpp line 44:

> 42: 
> 43: enum class NodeTypeCon {
> 44:   VECTOR  // Vector and PVectMask (e.g. XorV / XorVMask)

I think a separate enum value for `Vector` and `PVectMask` would be clearer.

src/hotspot/share/opto/genericOpts.hpp line 40:

> 38: // the caller's convention, e.g. nullptr for Ideal and the root for 
> Identity.
> 39: // So each optimization is declared with this macro.
> 40: #define DECLARE_GENERIC_OPT(opt_name) template<typename NodeClass> \

I would strongly advise against macro here.

-------------

PR Review Comment: https://git.openjdk.org/jdk/pull/32095#discussion_r4386271861
PR Review Comment: https://git.openjdk.org/jdk/pull/32095#discussion_r4386266315
PR Review Comment: https://git.openjdk.org/jdk/pull/32095#discussion_r4386260834

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