On Thu, 17 Apr 2025 18:03:47 GMT, Vladimir Ivanov <vliva...@openjdk.org> wrote:

>> Migrate Vector API math library (SVML and SLEEF) linkage from native code 
>> (in JVM) to Java FFM API.
>> 
>> Since FFM API doesn't support vector calling conventions yet, migration 
>> affects only symbol lookup for now. But it still enables significant 
>> simplifications on JVM side.
>> 
>> The patch consists of the following parts:
>>   * on-demand symbol lookup in Java code replaces eager lookup from native 
>> code during JVM startup;
>>   * 2 new VM intrinsics for vector calls (support unary and binary shapes) 
>> (code separated from unary/binary vector operations);
>>   * new internal interface to query supported CPU ISA extensions 
>> (`jdk.incubator.vector.CPUFeatures`) used for CPU dispatching.
>> 
>> `java.lang.foreign` API is used to perform symbol lookup in vector math 
>> library, then the address is cached and fed into corresponding JVM 
>> intrinsic, so C2 can turn it into a direct vector call in generated code.
>> 
>> Once `java.lang.foreign` supports vectors & vector calling conventions, VM 
>> intrinsics can go away. 
>> 
>> Performance is on par with original implementation (tested with 
>> microbenchmarks on linux-x64 and macosx-aarch64).
>> 
>> Testing: hs-tier1 - hs-tier6, microbenchmarks (on linux-x64 and 
>> macosx-aarch64)
>> 
>> Thanks!
>
> Vladimir Ivanov has updated the pull request with a new target base due to a 
> merge or a rebase. The incremental webrev excludes the unrelated changes 
> brought in by the merge/rebase. The pull request contains 24 additional 
> commits since the last revision:
> 
>  - Merge remote-tracking branch 'origin/master' into vector.math.01.java
>  - RVV and SVE adjustments
>  - fix broken merge
>  - Merge branch 'master' into vector.math.01.java
>  - Fix debugName handling
>  - Merge branch 'master' into vector.math.01.java
>  - RVV and SVE adjustments
>  - Merge branch 'master' into vector.math.01.java
>  - Fix windows-aarch64 build failure
>  - features_string -> cpu_info_string
>  - ... and 14 more: https://git.openjdk.org/jdk/compare/63ffaec1...88eacc48

src/jdk.incubator.vector/share/classes/jdk/incubator/vector/VectorMathLibrary.java
 line 75:

> 73:             return switch (StaticProperty.osArch()) {
> 74:                 case "amd64", "x86_64" -> SVML;
> 75:                 case "aarch64" -> SLEEF;

We should be supporting SLEEF on `riscv64`. Was there a specific motivation not 
to include it here?

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

PR Review Comment: https://git.openjdk.org/jdk/pull/24462#discussion_r2054281193

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