> This PR introduces the basic Ideal/Identity transformations for
> `VectorBlendNode`.
>
> The semantic of `VectorBlend(X, Y, M)` is: `M ? Y : X`.
>
> **Identity**:
>
> (VectorBlend X Y (Replicate -1)) => Y
> (VectorBlend X Y (MaskAll -1)) => Y
> (VectorBlend X Y (Replicate 0)) => X
> (VectorBlend X Y (MaskAll 0)) => X
>
>
> **Ideal**:
>
> (VectorBlend (VectorBlend X A M) B M) => (VectorBlend X B M)
> (VectorBlend A (VectorBlend B X M) M) => (VectorBlend A X M)
> (VectorBlend A B (XorV/XorVMask M -1)) => (VectorBlend B A M)
>
>
> Also corrects the VectorBlendNode header comment: across all backends (X86
> SSE/AVX, AArch64 NEON/SVE, RISC-V V) the active mask lane selects `vec2`
> (in(2)), and the inactive lane selects `vec1` (in(1)).
>
> JTReg and JMH tests are also added for each optimization pattern. All tests
> (tier1, tier2, and tier3) passed on AArch64 and X86 platforms.
>
> JMH benchmark test results:
>
> On a Nvidia Grace (Neoverse-V2) machine with 128-bit SVE2:
>
> Benchmark Unit Before Error After Error
> Uplift
> blendNegatedMaskInt ops/ms 7990.6 2.8 10215.2
> 11.0 1.3
> identityAllOnesInt ops/ms 3574.8 2.6 7967.1
> 0.3 2.2
> identityAllZerosLong ops/ms 3575.6 1.0 7966.0 3.6
> 2.2
> nestedBlendInnerLong ops/ms 3533.8 2.8 478573.0 3178.5 135.4
> nestedBlendOuterInt ops/ms 3537.6 3.4 472242.2 3034.2
> 133.5
>
>
> On an AWS Graviton3 (Neoverse-V1) machine with 256-bit SVE1:
>
> Benchmark Unit Before Error After Error
> Uplift
> blendNegatedMaskInt ops/ms 5171.9 5.2 8129.0
> 17.3 1.6
> identityAllOnesInt ops/ms 2722.0 0.1 5891.3
> 0.1 2.2
> identityAllZerosLong ops/ms 2722.4 0.1 5891.1 0.3
> 2.2
> nestedBlendInnerLong ops/ms 2697.6 0.0 312148.7 2366.4 115.7
> nestedBlendOuterInt ops/ms 2702.7 0.1 308686.0 2709.8
> 114.2
>
>
> On a Nvidia Grace (Neoverse-V2) machine with `-XX:UseSVE=0`:
>
> Benchmark Unit Before Error After Error
> Uplift
> blendNegatedMaskInt ops/ms 7718.1 1.9 9515.9
> 54.0 1.2
> identityAllOnesInt ops/ms 3581.9 0.6 8062.5
> 0.5 2.3
> identityAllZerosLong ops/ms 3582.7 0.6 8058.5 11.9
> 2.2
> nestedBlendInnerLong ops/ms 3529.6 1.4 476029.8 5190.2 134.9
> nestedBlendOuterInt ops/ms 3536.9 2.1 486060.0 3442.1
> 137.4
>
>
> On an AMD EPYC 9124 16-Core Processor with option `-XX:UseAVX=3`:
>
> Benchmark Unit Before Error After Error
> Uplift
> blendNegatedMaskInt ops/ms 36773.6 541.7 46467.4 499.4
> 1.3
> identityAllOnesInt ops/ms 5262.7 3.7 13644.7
> 12.1 2.6
> identityAllZerosLong ...
Eric Fang 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 three additional commits since the
last revision:
- Add JMH and JTReg tests for each optimization pattern and each type
- Merge branch 'master' into JDK-8384571-vector-blend-opt-pr1
- 8384571: C2: Add some basic IGVN optimization for VectorBlendNode
This PR introduces the basic Ideal/Identity transformations for
`VectorBlendNode`.
The semantic of `VectorBlend(X, Y, M)` is: `M ? Y : X`.
**Identity**:
```
(VectorBlend X Y (Replicate -1)) => Y
(VectorBlend X Y (MaskAll -1)) => Y
(VectorBlend X Y (Replicate 0)) => X
(VectorBlend X Y (MaskAll 0)) => X
```
**Ideal**:
```
(VectorBlend (VectorBlend X A M) B M) => (VectorBlend X B M)
(VectorBlend A (VectorBlend B X M) M) => (VectorBlend A X M)
(VectorBlend A B (XorV/XorVMask M -1)) => (VectorBlend B A M)
```
Also corrects the VectorBlendNode header comment: across all backends
(X86 SSE/AVX, AArch64 NEON/SVE, RISC-V V) the active mask lane selects
`vec2` (in(2)), and the inactive lane selects `vec1` (in(1)).
JTReg and JMH tests are also added for each optimization pattern. All
tests (tier1, tier2, and tier3) passed on AArch64 and X86 platforms.
JMH benchmark test results:
On a Nvidia Grace (Neoverse-V2) machine with 128-bit SVE2:
```
Benchmark Unit Before Error After Error Uplift
blendNegatedMaskInt ops/ms 7990.6 2.8 10215.2 11.0 1.3
identityAllOnesInt ops/ms 3574.8 2.6 7967.1 0.3 2.2
identityAllZerosLong ops/ms 3575.6 1.0 7966.0 3.6 2.2
nestedBlendInnerLong ops/ms 3533.8 2.8 478573.0 3178.5 135.4
nestedBlendOuterInt ops/ms 3537.6 3.4 472242.2 3034.2 133.5
```
On an AWS Graviton3 (Neoverse-V1) machine with 256-bit SVE1:
```
Benchmark Unit Before Error After Error Uplift
blendNegatedMaskInt ops/ms 5171.9 5.2 8129.0 17.3 1.6
identityAllOnesInt ops/ms 2722.0 0.1 5891.3 0.1 2.2
identityAllZerosLong ops/ms 2722.4 0.1 5891.1 0.3 2.2
nestedBlendInnerLong ops/ms 2697.6 0.0 312148.7 2366.4 115.7
nestedBlendOuterInt ops/ms 2702.7 0.1 308686.0 2709.8 114.2
```
On a Nvidia Grace (Neoverse-V2) machine with `-XX:UseSVE=0`:
```
Benchmark Unit Before Error After Error Uplift
blendNegatedMaskInt ops/ms 7718.1 1.9 9515.9 54.0 1.2
identityAllOnesInt ops/ms 3581.9 0.6 8062.5 0.5 2.3
identityAllZerosLong ops/ms 3582.7 0.6 8058.5 11.9 2.2
nestedBlendInnerLong ops/ms 3529.6 1.4 476029.8 5190.2 134.9
nestedBlendOuterInt ops/ms 3536.9 2.1 486060.0 3442.1 137.4
```
On an AMD EPYC 9124 16-Core Processor with option `-XX:UseAVX=3`:
```
Benchmark Unit Before Error After Error Uplift
blendNegatedMaskInt ops/ms 36773.6 541.7 46467.4 499.4 1.3
identityAllOnesInt ops/ms 5262.7 3.7 13644.7 12.1 2.6
identityAllZerosLong ops/ms 5272.4 3.4 13665.3 8.4 2.6
nestedBlendInnerLong ops/ms 5256.6 4.9 436643.3 14778.8 83.1
nestedBlendOuterInt ops/ms 5253.2 1.5 223851.3 106002.6
42.6
```
On an AMD EPYC 9124 16-Core Processor with option `-XX:UseAVX=2`:
```
Benchmark Unit Before Error After Error Uplift
blendNegatedMaskInt ops/ms 24335.3 32.1 30412.3 28.1 1.2
identityAllOnesInt ops/ms 5248.8 5.0 13677.5 18.4 2.6
identityAllZerosLong ops/ms 5248.8 2.2 13655.8 2.9 2.6
nestedBlendInnerLong ops/ms 5146.2 4.6 649242.6 1174.4 126.2
nestedBlendOuterInt ops/ms 5141.8 6.2 646255.2 10654.1 125.7
```
The microbenchmark shows a significant speedup. This is mainly because
this PR eliminates redundant computations inside the loop by hoisting
them out of the loop. At the same time, it reduces the number of IR
uses, which can in turn enable further optimizations.
-------------
Changes:
- all: https://git.openjdk.org/jdk/pull/31333/files
- new: https://git.openjdk.org/jdk/pull/31333/files/f8bedad7..d1cf7ec3
Webrevs:
- full: https://webrevs.openjdk.org/?repo=jdk&pr=31333&range=01
- incr: https://webrevs.openjdk.org/?repo=jdk&pr=31333&range=00-01
Stats: 239586 lines in 2701 files changed: 117390 ins; 105340 del; 16856 mod
Patch: https://git.openjdk.org/jdk/pull/31333.diff
Fetch: git fetch https://git.openjdk.org/jdk.git pull/31333/head:pull/31333
PR: https://git.openjdk.org/jdk/pull/31333
