RFR: 8310691: [REDO] [vectorapi] Refactor VectorShuffle implementation [v4]
Quan Anh Mai
qamai at openjdk.org
Tue Nov 26 19:33:04 UTC 2024
> Hi,
>
> This is just a redo of https://github.com/openjdk/jdk/pull/13093. mostly just the revert of the backout.
>
> Regarding the related issues:
>
> - [JDK-8306008](https://bugs.openjdk.org/browse/JDK-8306008) and [JDK-8309531](https://bugs.openjdk.org/browse/JDK-8309531) have been fixed before the backout.
> - [JDK-8309373](https://bugs.openjdk.org/browse/JDK-8309373) was due to missing `ForceInline` on `AbstractVector::toBitsVectorTemplate`
> - [JDK-8306592](https://bugs.openjdk.org/browse/JDK-8306592), I have not been able to find the root causes. I'm not sure if this is a blocker, now I cannot even build x86-32 tests.
>
> Finally, I moved some implementation of public methods and methods that call into intrinsics to the concrete class as that may help the compiler know the correct types of the variables.
>
> Please take a look and leave reviews. Thanks a lot.
>
> The description of the original PR:
>
> This patch reimplements `VectorShuffle` implementations to be a vector of the bit type. Currently, `VectorShuffle` is stored as a byte array, and would be expanded upon usage. This poses several drawbacks:
>
> Inefficient conversions between a shuffle and its corresponding vector. This hinders the performance when the shuffle indices are not constant and are loaded or computed dynamically.
> Redundant expansions in `rearrange` operations. On all platforms, it seems that a shuffle index vector is always expanded to the correct type before executing the `rearrange` operations.
> Some redundant intrinsics are needed to support this handling as well as special considerations in the C2 compiler.
> Range checks are performed using `VectorShuffle::toVector`, which is inefficient for FP types since both FP conversions and FP comparisons are more expensive than the integral ones.
> Upon these changes, a `rearrange` can emit more efficient code:
>
> var species = IntVector.SPECIES_128;
> var v1 = IntVector.fromArray(species, SRC1, 0);
> var v2 = IntVector.fromArray(species, SRC2, 0);
> v1.rearrange(v2.toShuffle()).intoArray(DST, 0);
>
> Before:
> movabs $0x751589fa8,%r10 ; {oop([I{0x0000000751589fa8})}
> vmovdqu 0x10(%r10),%xmm2
> movabs $0x7515a0d08,%r10 ; {oop([I{0x00000007515a0d08})}
> vmovdqu 0x10(%r10),%xmm1
> movabs $0x75158afb8,%r10 ; {oop([I{0x000000075158afb8})}
> vmovdqu 0x10(%r10),%xmm0
> vpand -0xddc12(%rip),%xmm0,%xmm0 # Stub::vector_int_to_byte_mask
> ; {ex...
Quan Anh Mai has updated the pull request incrementally with one additional commit since the last revision:
fix asserts
-------------
Changes:
- all: https://git.openjdk.org/jdk/pull/21042/files
- new: https://git.openjdk.org/jdk/pull/21042/files/4cee07eb..36ee750a
Webrevs:
- full: https://webrevs.openjdk.org/?repo=jdk&pr=21042&range=03
- incr: https://webrevs.openjdk.org/?repo=jdk&pr=21042&range=02-03
Stats: 11 lines in 7 files changed: 7 ins; 0 del; 4 mod
Patch: https://git.openjdk.org/jdk/pull/21042.diff
Fetch: git fetch https://git.openjdk.org/jdk.git pull/21042/head:pull/21042
PR: https://git.openjdk.org/jdk/pull/21042
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