stdarch subtree update #150639

usamoi · 2026-01-03T09:37:27Z

Subtree update of stdarch to rust-lang/stdarch@67cdf84.

Created using https://github.com/rust-lang/josh-sync.

…ly use `f16` in the signature

Some test utility functions (e.g., `assert_eq_m128`) have been refactored so they are not unsafe. Many test functions (`test_mm_*`) do not call any unsafe function (besides needing target features) anymore, so they do not need to be `unsafe fn`.

(Partially) Stabilize `stdarch_neon_f16`

Fix some tests so they test the correct function

(Partially) Stabilize AVX512-FP16

x86: remove "unsafe" from tests that do not need it

This updates the rust-version file to 4862272.

Pull recent changes from https://github.com/rust-lang/rust via Josh. Upstream ref: 4862272 Filtered ref: cd67a857259ae6c8e166020f097dd070d6c16fb3 Upstream diff: rust-lang/rust@8401398...4862272 This merge was created using https://github.com/rust-lang/josh-sync.

Clarify documentation around "undefined" bits in intrinsics.

Use LLVM intrinsics for `madd` intrinsics

`repr(packed)` structs do not have a well-defined layout

Change `repr(packed)` struct to `repr(C, packed)`

Rustc pull update

rustbot · 2026-01-03T09:38:36Z

stdarch is developed in its own repository. If possible, consider making this change to rust-lang/stdarch instead.

cc @Amanieu, @folkertdev, @sayantn

usamoi · 2026-01-03T09:39:48Z

r? @sayantn

usamoi · 2026-01-03T09:42:05Z

85f3ba3 (and 5e4168b for passing miri tests in CI if it's needed in beta) should be backported to beta, to fix #150560.

@rustbot label +beta-nominated

rustbot · 2026-01-03T10:50:16Z

The Miri subtree was changed

cc @rust-lang/miri

RalfJung · 2026-01-03T13:19:47Z

We've supported SSE2 and AVX for a while so regressing this would be unfortunate. Ideally, we'd instead partially revert the PR that removed the LLVM intrinsic shims: 8d597aa.

Generally, I find it odd that someone would propose to remove tests without even mentioning this or bringing it up for discussion? The default fix for failing tests should not be to remove the test...

usamoi · 2026-01-03T13:38:27Z

Generally, I find it odd that someone would propose to remove tests without even mentioning this or bringing it up for discussion? The default fix for failing tests should not be to remove the test...

Sorry. I removed that commit and added a commit to partially revert 8d597aa now.

RalfJung · 2026-01-03T15:06:16Z

The Miri part LGTM, thanks!

sayantn · 2026-01-03T18:08:53Z

LGTM too. If I am not mistaken, the beta backport is to be handled in a separate PR, and this should be merged normally, right?

usamoi · 2026-01-03T18:21:41Z

If I am not mistaken, the beta backport is to be handled in a separate PR, and this should be merged normally, right?

Yes, according to https://forge.rust-lang.org/release/backporting.html#beta-backporting-in-rust-langrust.

sayantn · 2026-01-03T18:45:06Z

Ok then, let's get the ball rolling

@bors r+

bors · 2026-01-03T18:45:10Z

📌 Commit 5e4168b has been approved by sayantn

It is now in the queue for this repository.

bors · 2026-01-03T19:31:16Z

⌛ Testing commit 5e4168b with merge 7ecabfa...

bors · 2026-01-03T22:46:28Z

☀️ Test successful - checks-actions
Approved by: sayantn
Pushing 7ecabfa to main...

github-actions · 2026-01-03T22:49:31Z

What is this?

This is an experimental post-merge analysis report that shows differences in test outcomes between the merged PR and its parent PR.

Comparing 1d22b96 (parent) -> 7ecabfa (this PR)

Test differences

Show 2 test diffs

2 doctest diffs were found. These are ignored, as they are noisy.

Test dashboard

Run

cargo run --manifest-path src/ci/citool/Cargo.toml -- \
    test-dashboard 7ecabfaaf1a58172cdd71f7661cf6589ddf7928f --output-dir test-dashboard

And then open test-dashboard/index.html in your browser to see an overview of all executed tests.

Job duration changes

dist-riscv64-linux: 4969.9s -> 6053.6s (+21.8%)
x86_64-msvc-1: 8293.5s -> 9440.8s (+13.8%)
x86_64-msvc-2: 9126.9s -> 8066.6s (-11.6%)
aarch64-msvc-2: 5710.0s -> 6316.4s (+10.6%)
i686-gnu-1: 6840.6s -> 7514.4s (+9.9%)
aarch64-msvc-1: 7433.3s -> 6759.4s (-9.1%)
dist-apple-various: 3543.6s -> 3843.0s (+8.4%)
x86_64-gnu: 8215.2s -> 7543.0s (-8.2%)
dist-x86_64-solaris: 5068.5s -> 5439.0s (+7.3%)
tidy: 168.2s -> 156.1s (-7.1%)

How to interpret the job duration changes?

Job durations can vary a lot, based on the actual runner instance
that executed the job, system noise, invalidated caches, etc. The table above is provided
mostly for t-infra members, for simpler debugging of potential CI slow-downs.

rust-timer · 2026-01-03T23:28:01Z

Finished benchmarking commit (7ecabfa): comparison URL.

Overall result: ❌ regressions - no action needed

@rustbot label: -perf-regression

Instruction count

Our most reliable metric. Used to determine the overall result above. However, even this metric can be noisy.

	mean	range	count
Regressions ❌ (primary)	-	-	0
Regressions ❌ (secondary)	0.1%	[0.1%, 0.2%]	2
Improvements ✅ (primary)	-	-	0
Improvements ✅ (secondary)	-	-	0
All ❌✅ (primary)	-	-	0

Max RSS (memory usage)

Results (primary 1.8%, secondary 6.1%)

A less reliable metric. May be of interest, but not used to determine the overall result above.

	mean	range	count
Regressions ❌ (primary)	1.8%	[1.8%, 1.8%]	1
Regressions ❌ (secondary)	6.1%	[6.1%, 6.1%]	1
Improvements ✅ (primary)	-	-	0
Improvements ✅ (secondary)	-	-	0
All ❌✅ (primary)	1.8%	[1.8%, 1.8%]	1

Cycles

Results (secondary 2.3%)

A less reliable metric. May be of interest, but not used to determine the overall result above.

	mean	range	count
Regressions ❌ (primary)	-	-	0
Regressions ❌ (secondary)	2.3%	[2.3%, 2.3%]	1
Improvements ✅ (primary)	-	-	0
Improvements ✅ (secondary)	-	-	0
All ❌✅ (primary)	-	-	0

Binary size

Results (primary -0.0%, secondary -0.1%)

A less reliable metric. May be of interest, but not used to determine the overall result above.

	mean	range	count
Regressions ❌ (primary)	-	-	0
Regressions ❌ (secondary)	-	-	0
Improvements ✅ (primary)	-0.0%	[-0.0%, -0.0%]	15
Improvements ✅ (secondary)	-0.1%	[-0.1%, -0.0%]	5
All ❌✅ (primary)	-0.0%	[-0.0%, -0.0%]	15

Bootstrap: 473.382s -> 475.226s (0.39%)
Artifact size: 390.84 MiB -> 390.78 MiB (-0.02%)

[beta] backports - Revert "Rollup merge of #149147 - chenyukang:yukang-fix-unused_assignments-macro-gen-147648, r=JonathanBrouwer" #149657 - Don't lint on interior mutable `const` item coming from derefs #150166 - stdarch subtree update #150639 (partial) r? cuviper

[beta] backports - Revert "Rollup merge of #149147 - chenyukang:yukang-fix-unused_assignments-macro-gen-147648, r=JonathanBrouwer" #149657 - Don't lint on interior mutable `const` item coming from derefs #150166 - stdarch subtree update #150639 (partial) - Update bors configuration #150308 - Update bors e-mail lookup #150783 - Make verify-channel.sh script compatible with new bors #150759 r? cuviper

sayantn and others added 17 commits December 4, 2025 22:10

(Partially) Stabilize AVX512-FP16, except for functions that explicit…

109e097

…ly use `f16` in the signature

(partially) stablize stdarch_neon_f16

e9b75fa

Merge pull request rust-lang#1922 from usamoi/stdarch_neon_f16_stablize

9bd9244

(Partially) Stabilize `stdarch_neon_f16`

Fix some tests so they test the correct function

8d66e58

Merge pull request rust-lang#1983 from eduardosm/tests

cb3952a

Fix some tests so they test the correct function

Merge pull request rust-lang#1905 from sayantn/stabilize-avx512fp16

e116716

(Partially) Stabilize AVX512-FP16

Merge pull request rust-lang#1981 from eduardosm/unsafe-tests

56a8bfa

x86: remove "unsafe" from tests that do not need it

Prepare for merging from rust-lang/rust

6ba984f

This updates the rust-version file to 4862272.

Clarify documentation around "undefined" bits in intrinsics.

c571336

Merge pull request rust-lang#1986 from veluca93/main

da57c64

Clarify documentation around "undefined" bits in intrinsics.

Use LLVM intrinsics for madd intrinsics

344fc51

Merge pull request rust-lang#1985 from usamoi/vpmaddwd

85f3ba3

Use LLVM intrinsics for `madd` intrinsics

Change repr(packed) struct to repr(C, packed)

f41fa64

`repr(packed)` structs do not have a well-defined layout

Merge pull request rust-lang#1988 from eduardosm/packed-struct

c914627

Change `repr(packed)` struct to `repr(C, packed)`

Merge pull request rust-lang#1984 from rust-lang/rustc-pull

7434dd6

Rustc pull update

rustbot added S-waiting-on-author Status: This is awaiting some action (such as code changes or more information) from the author. T-libs Relevant to the library team, which will review and decide on the PR/issue. labels Jan 3, 2026

usamoi marked this pull request as ready for review January 3, 2026 09:38

rustbot added S-waiting-on-review Status: Awaiting review from the assignee but also interested parties. and removed S-waiting-on-author Status: This is awaiting some action (such as code changes or more information) from the author. labels Jan 3, 2026

rustbot assigned sayantn Jan 3, 2026

rustbot added the beta-nominated Nominated for backporting to the compiler in the beta channel. label Jan 3, 2026

This comment has been minimized.

Sign in to view

partially revert rust-lang@8d597aa

5e4168b

usamoi force-pushed the stdarch branch from d04ebf2 to 5e4168b Compare January 3, 2026 13:37

bors 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 Jan 3, 2026

bors added the merged-by-bors This PR was explicitly merged by bors. label Jan 3, 2026

bors merged commit 7ecabfa into rust-lang:main Jan 3, 2026
12 checks passed

rustbot added this to the 1.94.0 milestone Jan 3, 2026

Amanieu added the beta-accepted Accepted for backporting to the compiler in the beta channel. label Jan 6, 2026

usamoi deleted the stdarch branch January 7, 2026 12:59

usamoi mentioned this pull request Jan 7, 2026

Use LLVM intrinsics for madd intrinsics rust-lang/stdarch#1985

Merged

cuviper mentioned this pull request Jan 9, 2026

[beta] backports #150848

Merged

cuviper modified the milestones: 1.94.0, 1.93.0 Jan 9, 2026

cuviper removed the beta-nominated Nominated for backporting to the compiler in the beta channel. label Jan 9, 2026

Uh oh!

stdarch subtree update #150639

stdarch subtree update #150639

Uh oh!

Conversation

usamoi commented Jan 3, 2026

Uh oh!

rustbot commented Jan 3, 2026

Uh oh!

usamoi commented Jan 3, 2026

Uh oh!

usamoi commented Jan 3, 2026 • edited Loading Uh oh! There was an error while loading. Please reload this page.

Uh oh!

Uh oh!

This comment has been minimized.

rustbot commented Jan 3, 2026

Uh oh!

RalfJung commented Jan 3, 2026 • edited Loading Uh oh! There was an error while loading. Please reload this page.

Uh oh!

Uh oh!

usamoi commented Jan 3, 2026

Uh oh!

RalfJung commented Jan 3, 2026

Uh oh!

sayantn commented Jan 3, 2026 • edited Loading Uh oh! There was an error while loading. Please reload this page.

Uh oh!

Uh oh!

usamoi commented Jan 3, 2026

Uh oh!

sayantn commented Jan 3, 2026

Uh oh!

bors commented Jan 3, 2026

Uh oh!

bors commented Jan 3, 2026

Uh oh!

bors commented Jan 3, 2026

Uh oh!

Uh oh!

github-actions bot commented Jan 3, 2026

Test differences

Job duration changes

Uh oh!

rust-timer commented Jan 3, 2026

Overall result: ❌ regressions - no action needed

Instruction count

Max RSS (memory usage)

Cycles

Binary size

Uh oh!

Reviewers

Assignees

Labels

Projects

Milestone

Development

Uh oh!

12 participants

usamoi commented Jan 3, 2026 •

edited

Loading

RalfJung commented Jan 3, 2026 •

edited

Loading

sayantn commented Jan 3, 2026 •

edited

Loading