Add codegen test for SLP vectorization #151958

chahar-ritik · 2026-02-01T16:22:19Z

This PR adds a codegen regression test for #142519. A regression in LLVM to fail to auto-vectorize, leading to significant performance loss.

The SLP vectorizer correctly groups the 4-byte operations into <4 x i8> vectors.

The loop state is maintained in SIMD registers (phi <4 x i8>).

The test remains robust across architectures (AArch64 vs x86_64) by allowing flexible store types (i32 or <4 x i8>).

rustbot · 2026-02-01T16:22:24Z

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nikic · 2026-02-01T16:34:55Z

This should probably be only-x86_64 (it's presumably not going to produce vectors ops on targets without vector support).

chahar-ritik · 2026-02-01T16:47:04Z

Thanks for the guidance, @nikic I'm a new contributor, so I appreciate the help with the test directives. I've updated the test to only-x86_64

jieyouxu

One nit

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jieyouxu · 2026-02-02T00:53:41Z

tests/codegen-llvm/slp-vectorization-mul3.rs

@@ -0,0 +1,25 @@
+//@ only-x86_64


Suggestion: please leave a backlink to #142519, e.g.

//! Regression test for #142519.

jieyouxu · 2026-02-02T00:54:23Z

@rustbot author

rustbot · 2026-02-02T00:54:27Z

Reminder, once the PR becomes ready for a review, use @rustbot ready.

jieyouxu

Thanks

@bors r+ rollup squash

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rust-bors · 2026-02-02T02:25:56Z

📌 Commit c64f9a0 has been approved by jieyouxu

It is now in the queue for this repository.

…-test, r=jieyouxu Add codegen test for SLP vectorization close: rust-lang#142519 This PR adds a codegen regression test for rust-lang#142519. A regression in LLVM to fail to auto-vectorize, leading to significant performance loss. The SLP vectorizer correctly groups the 4-byte operations into <4 x i8> vectors. The loop state is maintained in SIMD registers (phi <4 x i8>). The test remains robust across architectures (AArch64 vs x86_64) by allowing flexible store types (i32 or <4 x i8>).

Rollup of 5 pull requests Successful merges: - #151825 (more float constants) - #151958 (Add codegen test for SLP vectorization) - #151974 (Update documentation for `Result::ok()`) - #151978 (Query cleanups) - #151979 (Fix uninitialized UEFI globals in tests)

jhpratt · 2026-02-02T08:26:23Z

@bors r-

#151984 (comment)

rust-bors · 2026-02-02T08:26:29Z

Commit c64f9a0 has been unapproved.

This PR was contained in a rollup (#151984), which was also unapproved.

nikic · 2026-02-02T09:53:06Z

tests/codegen-llvm/slp-vectorization-mul3.rs

Missing min-llvm-version.

chahar-ritik · 2026-02-02T10:16:10Z

@rustbot ready

tests/codegen-llvm/slp-vectorization-mul3.rs

Co-authored-by: Nikita Popov <github@npopov.com>

jieyouxu · 2026-02-02T14:44:33Z

@bors r+ squash

rust-bors · 2026-02-02T14:44:35Z

📌 Commit 8476e89 has been approved by jieyouxu

It is now in the queue for this repository.

…-test, r=jieyouxu Add codegen test for SLP vectorization close: rust-lang#142519 This PR adds a codegen regression test for rust-lang#142519. A regression in LLVM to fail to auto-vectorize, leading to significant performance loss. The SLP vectorizer correctly groups the 4-byte operations into <4 x i8> vectors. The loop state is maintained in SIMD registers (phi <4 x i8>). The test remains robust across architectures (AArch64 vs x86_64) by allowing flexible store types (i32 or <4 x i8>).

…uwer Rollup of 4 pull requests Successful merges: - #151958 (Add codegen test for SLP vectorization) - #151974 (Update documentation for `Result::ok()`) - #151975 (Work around rustfmt giving up on a large expression) - #151999 (attribute parsing: pass recovery mode to Parser.)

Rollup of 11 pull requests Successful merges: - #151378 (Codegen tests for Arm Cortex-R82) - #151936 (Move the `fingerprint_style` special case into `DepKindVTable` creation) - #152018 (Move bigint helper tracking issues) - #151958 (Add codegen test for SLP vectorization) - #151974 (Update documentation for `Result::ok()`) - #151975 (Work around rustfmt giving up on a large expression) - #151990 (Fix missing unused_variables lint when using a match guard) - #151995 (stabilize ptr_as_ref_unchecked) - #151999 (attribute parsing: pass recovery mode to Parser.) - #152009 (Port rustc_preserve_ub_checks to attr parser) - #152022 (rustc-dev-guide subtree update) Failed merges: - #151968 (Remove `HasDepContext` by merging it into `QueryContext`)

Rollup merge of #151958 - chahar-ritik:add-slp-vectorization-test, r=jieyouxu Add codegen test for SLP vectorization close: #142519 This PR adds a codegen regression test for #142519. A regression in LLVM to fail to auto-vectorize, leading to significant performance loss. The SLP vectorizer correctly groups the 4-byte operations into <4 x i8> vectors. The loop state is maintained in SIMD registers (phi <4 x i8>). The test remains robust across architectures (AArch64 vs x86_64) by allowing flexible store types (i32 or <4 x i8>).

Rollup of 11 pull requests Successful merges: - rust-lang/rust#151378 (Codegen tests for Arm Cortex-R82) - rust-lang/rust#151936 (Move the `fingerprint_style` special case into `DepKindVTable` creation) - rust-lang/rust#152018 (Move bigint helper tracking issues) - rust-lang/rust#151958 (Add codegen test for SLP vectorization) - rust-lang/rust#151974 (Update documentation for `Result::ok()`) - rust-lang/rust#151975 (Work around rustfmt giving up on a large expression) - rust-lang/rust#151990 (Fix missing unused_variables lint when using a match guard) - rust-lang/rust#151995 (stabilize ptr_as_ref_unchecked) - rust-lang/rust#151999 (attribute parsing: pass recovery mode to Parser.) - rust-lang/rust#152009 (Port rustc_preserve_ub_checks to attr parser) - rust-lang/rust#152022 (rustc-dev-guide subtree update) Failed merges: - rust-lang/rust#151968 (Remove `HasDepContext` by merging it into `QueryContext`)

Add codegen test for SLP vectorization

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rustbot assigned jieyouxu Feb 1, 2026

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chahar-ritik added 2 commits February 1, 2026 22:09

fix: remove trailing newline for tidy

0a60bd6

Restrict test to x86_64 per reviewer feedback

1c396d2

jieyouxu reviewed Feb 2, 2026

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Add backlink to issue

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jhpratt mentioned this pull request Feb 2, 2026

Rollup of 5 pull requests #151984

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tests/codegen-llvm/slp-vectorization-mul3.rs

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Missing min-llvm-version.

chahar-ritik added 2 commits February 2, 2026 15:38

Fix SLP vectorization test CHECK patterns

95ac567

fix: add min-llvm-version

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fix: remove space for tidy and only for x86_64

6176945

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tests/codegen-llvm/slp-vectorization-mul3.rs Outdated Show resolved Hide resolved

Update min-llvm-version: 22

8476e89

Co-authored-by: Nikita Popov <github@npopov.com>

chahar-ritik requested a review from jieyouxu February 2, 2026 13:43

rust-bors bot added S-waiting-on-bors Status: Waiting on bors to run and complete tests. Bors will change the label on completion. and removed S-waiting-on-review Status: Awaiting review from the assignee but also interested parties. labels Feb 2, 2026

JonathanBrouwer mentioned this pull request Feb 2, 2026

Rollup of 4 pull requests #152002

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jhpratt mentioned this pull request Feb 3, 2026

Rollup of 11 pull requests #152025

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rust-bors bot merged commit e2c5b89 into rust-lang:main Feb 3, 2026
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rustbot added this to the 1.95.0 milestone Feb 3, 2026

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Add codegen test for SLP vectorization #151958

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