On Wed, 28 May 2025 12:18:15 GMT, Emanuel Peter <epe...@openjdk.org> wrote:
>> erifan 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 10 additional commits since
>> the last revision:
>>
>> - Refactor the JTReg tests for compare.xor(maskAll)
>>
>> Also made a bit change to support pattern `VectorMask.fromLong()`.
>> - Merge branch 'master' into JDK-8354242
>> - Refactor code
>>
>> Add a new function XorVNode::Ideal_XorV_VectorMaskCmp to do this
>> optimization, making the code more modular.
>> - Merge branch 'master' into JDK-8354242
>> - Update the jtreg test
>> - Merge branch 'master' into JDK-8354242
>> - Addressed some review comments
>>
>> 1. Call VectorNode::Ideal() only once in XorVNode::Ideal.
>> 2. Improve code comments.
>> - Merge branch 'master' into JDK-8354242
>> - Merge branch 'master' into JDK-8354242
>> - 8354242: VectorAPI: combine vector not operation with compare
>>
>> This patch optimizes the following patterns:
>> For integer types:
>> ```
>> (XorV (VectorMaskCmp src1 src2 cond) (Replicate -1))
>> => (VectorMaskCmp src1 src2 ncond)
>> (XorVMask (VectorMaskCmp src1 src2 cond) (MaskAll m1))
>> => (VectorMaskCmp src1 src2 ncond)
>> ```
>> cond can be eq, ne, le, ge, lt, gt, ule, uge, ult and ugt, ncond is the
>> negative comparison of cond.
>>
>> For float and double types:
>> ```
>> (XorV (VectorMaskCast (VectorMaskCmp src1 src2 cond)) (Replicate -1))
>> => (VectorMaskCast (VectorMaskCmp src1 src2 ncond))
>> (XorVMask (VectorMaskCast (VectorMaskCmp src1 src2 cond)) (MaskAll m1))
>> => (VectorMaskCast (VectorMaskCmp src1 src2 ncond))
>> ```
>> cond can be eq or ne.
>>
>> Benchmarks on Nvidia Grace machine with 128-bit SVE2:
>> With option `-XX:UseSVE=2`:
>> ```
>> Benchmark Unit Before Score Error After
>> Score Error Uplift
>> testCompareEQMaskNotByte ops/s 7912127.225 2677.289518
>> 10266136.26 8955.008548 1.29
>> testCompareEQMaskNotDouble ops/s 884737.6799 446.963779
>> 1179760.772 448.031844 1.33
>> testCompareEQMaskNotFloat ops/s 1765045.787 682.332214
>> 2359520.803 896.305743 1.33
>> testCompareEQMaskNotInt ops/s 1787221.411 977.743935
>> 2353952.519 960.069976 1.31
>> testCompareEQMaskNotLong ops/s 895297.1974 673.44808
>> 1178449.02 323.804205 1.31
>> testCompareEQMaskNotShort ops/s 3339987.002 3415.2226
>> 4712761.965 2110.862053 1.41
>> testCompareGEMaskNotByte ops/s 7907615.16 4...
>
> src/hotspot/share/opto/vectornode.cpp line 2251:
>
>> 2249: predicate_node, vt);
>> 2250: if (vmcast_vt != nullptr) {
>> 2251: // We optimized out an VectorMaskCast, and in order to ensure type
>
> Suggestion:
>
> // We optimized out a VectorMaskCast, and in order to ensure type
Done.
> src/hotspot/share/opto/vectornode.cpp line 2253:
>
>> 2251: // We optimized out an VectorMaskCast, and in order to ensure type
>> 2252: // correctness, we need to regenerate one. VectorMaskCast will be
>> encoded as
>> 2253: // empty for types with the same size.
>
> Suggestion:
>
> // a no-op (identity function) for types with the same size.
>
> Or what do you mean by "empty"? `TOP`? All zeros?
I mean `no-op`. Done, thanks.
> test/hotspot/jtreg/compiler/vectorapi/VectorMaskCompareNotTest.java line 96:
>
>> 94: Generator<Long> lGen = RD.uniformLongs(Long.MIN_VALUE,
>> Long.MAX_VALUE);
>> 95: Generator<Float> fGen = RD.uniformFloats(Float.MIN_VALUE,
>> Float.MAX_VALUE);
>> 96: Generator<Double> dGen = RD.uniformDoubles(Double.MIN_VALUE,
>> Double.MAX_VALUE);
>
> Are you sure you only want to draw from the uniform distribution?
> If you don't super care about the distribution, please just take
> `RD.ints/longs/floats/doubles()`.
> That way, you get all sorts of distributions, and also some that include NaN
> values etc. I think that would be important for your float cmp cases, no?
For float and double, we have to use the uniform distribution, because we have
to make sure `NAN` is not generated. I added some comments about the reasons.
For other types, changed to use `RD.ints/longs`.
We have covered the special cases like +/- Inf, NaN.
-------------
PR Review Comment: https://git.openjdk.org/jdk/pull/24674#discussion_r2128376851
PR Review Comment: https://git.openjdk.org/jdk/pull/24674#discussion_r2128378888
PR Review Comment: https://git.openjdk.org/jdk/pull/24674#discussion_r2128375032
