On Sun, 6 Oct 2024 08:32:20 GMT, Quan Anh Mai <qa...@openjdk.org> wrote:
>> 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_byt... > > Quan Anh Mai has updated the pull request with a new target base due to a > merge or a rebase. The pull request now contains one commit: > > [vectorapi] Refactor VectorShuffle implementation src/hotspot/cpu/x86/x86.ad line 2172: > 2170: > 2171: // Return true if Vector::rearrange needs preparation of the shuffle > argument > 2172: bool Matcher::vector_needs_load_shuffle(BasicType elem_bt, int vlen) { I think the name needs to be more expressive. If I read it alone, then I would think that it is about all kinds of vectors ... and it is confusing because what is a "load shuffle"? Are we shuffling loads or loading shuffles? src/hotspot/share/opto/vectornode.hpp line 1618: > 1616: public: > 1617: VectorLoadShuffleNode(Node* in, const TypeVect* vt) > 1618: : VectorNode(in, vt) {} Can you add a comment above "class VectorLoadShuffleNode" to say what its semantics are? ------------- PR Review Comment: https://git.openjdk.org/jdk/pull/21042#discussion_r1801531980 PR Review Comment: https://git.openjdk.org/jdk/pull/21042#discussion_r1801536233
