On Wed, 28 May 2025 12:14:56 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 2244:
>
>> 2242: // BoolTest doesn't support unsigned comparisons.
>> 2243: BoolTest::mask neg_cond =
>> 2244: (BoolTest::mask) (((VectorMaskCmpNode*) in1)->get_predicate() ^
>> 4);
>
> What is the hard-coded `^ 4` here? This whole line looks like we are looking
> at internals of the `VectorMaskCmpNode` or its predicate, and we should
> probably do that in some method there? Or maybe it should be part of the
> `BoolTest(::mask)` interface?
Also: You now cast `(VectorMaskCmpNode*) in1` twice. Can we not do
`as_VectorMaskCmp()`? Or could we at least cast it only once, and then use it
as `in1_mask_cmp` instead?
> test/hotspot/jtreg/compiler/vectorapi/VectorMaskCompareNotTest.java line 237:
>
>> 235: // Byte tests
>> 236: @Test
>> 237: @IR(counts = { IRNode.XOR_V_MASK, "= 0", IRNode.XOR_VB, "= 0" },
>
> Could you still assert the presence of some other vectors, just to make sure
> we are indeed getting vectors here?
Not testing for any present vectors makes me a little nervous: what if we just
don't get any vectors because inlining fails or something else silly happens?
-------------
PR Review Comment: https://git.openjdk.org/jdk/pull/24674#discussion_r2111701943
PR Review Comment: https://git.openjdk.org/jdk/pull/24674#discussion_r2111728478
