Update to LLVM 22 by nikic · Pull Request #150722 · rust-lang/rust

nikic · 2026-01-06T11:26:00Z

View all comments

Scheduled release date: Feb 24
1.94 becomes stable: Mar 5

Changes:

Update to rc2, with one patch to work around our outdated illumos sysroot (rust-lang/llvm-project@41256ab).
Update the host toolchain as well, otherwise we lose cross-language LTO, in particular for jemalloc.
Adjust one loongarch assembly test. The split into r and s variants is based on the suggestion in tests: fix loongarch test for new LLVM 23 codegen #151134.

Depends on:

rustbot · 2026-01-06T11:26:03Z

These commits modify compiler targets.
(See the Target Tier Policy.)

rustbot · 2026-01-06T11:26:05Z

⚠️ Warning ⚠️

Some commits in this PR modify submodules.

If this was not intentional, see I changed a submodule on accident in the rustc dev guide.

nikic · 2026-01-06T11:39:10Z

@bors try @rust-timer queue

Update to LLVM 22

rust-bors · 2026-01-06T14:36:15Z

☀️ Try build successful (CI)
Build commit: dabe9cd (dabe9cd2e5a1630ac5ed5f1b87f891b6dc563025, parent: da476f1942868cdf94ed88b01ea31170cfe95047)

rust-timer · 2026-01-06T15:17:47Z

Finished benchmarking commit (dabe9cd): comparison URL.

Overall result: ❌✅ regressions and improvements - please read the text below

Benchmarking this pull request means it may be perf-sensitive – we'll automatically label it not fit for rolling up. You can override this, but we strongly advise not to, due to possible changes in compiler perf.

Next Steps: If you can justify the regressions found in this try perf run, please do so in sufficient writing along with @rustbot label: +perf-regression-triaged. If not, please fix the regressions and do another perf run. If its results are neutral or positive, the label will be automatically removed.

@bors rollup=never
@rustbot label: -S-waiting-on-perf +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)	0.9%	[0.2%, 8.9%]	228
Regressions ❌ (secondary)	1.4%	[0.2%, 8.0%]	260
Improvements ✅ (primary)	-0.8%	[-1.1%, -0.3%]	6
Improvements ✅ (secondary)	-2.2%	[-8.0%, -0.2%]	28
All ❌✅ (primary)	0.9%	[-1.1%, 8.9%]	234

Max RSS (memory usage)

Results (primary 1.0%, secondary -1.3%)

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

	mean	range	count
Regressions ❌ (primary)	1.0%	[0.8%, 1.3%]	2
Regressions ❌ (secondary)	1.8%	[0.9%, 2.4%]	8
Improvements ✅ (primary)	-	-	0
Improvements ✅ (secondary)	-3.7%	[-4.8%, -2.6%]	10
All ❌✅ (primary)	1.0%	[0.8%, 1.3%]	2

Cycles

Results (primary 3.2%, secondary 2.1%)

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

	mean	range	count
Regressions ❌ (primary)	3.2%	[1.6%, 10.2%]	19
Regressions ❌ (secondary)	3.3%	[1.3%, 7.4%]	38
Improvements ✅ (primary)	-	-	0
Improvements ✅ (secondary)	-4.8%	[-7.5%, -2.5%]	7
All ❌✅ (primary)	3.2%	[1.6%, 10.2%]	19

Binary size

Results (primary -0.6%, secondary -1.1%)

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

	mean	range	count
Regressions ❌ (primary)	0.1%	[0.1%, 0.1%]	4
Regressions ❌ (secondary)	2.6%	[0.1%, 5.1%]	2
Improvements ✅ (primary)	-0.8%	[-1.5%, -0.1%]	14
Improvements ✅ (secondary)	-1.1%	[-3.9%, -0.0%]	93
All ❌✅ (primary)	-0.6%	[-1.5%, 0.1%]	18

Bootstrap: 473.133s -> 480.877s (1.64%)
Artifact size: 390.77 MiB -> 402.18 MiB (2.92%)

rust-bors · 2026-01-06T18:45:25Z

☔ The latest upstream changes made this pull request unmergeable. Please resolve the merge conflicts.

bors · 2026-01-06T19:43:13Z

☔ The latest upstream changes (presumably #150726) made this pull request unmergeable. Please resolve the merge conflicts.

nikic · 2026-01-08T11:49:52Z

Based on helloworld, the perf regressions seem to be related to the allocator somehow. Previously tcache_alloc_small_hard was called 3 times, now it's called 189 times. The total number of allocations is smaller, but the time spent in the allocator is larger.

nikic · 2026-01-08T14:29:53Z

Or maybe the issue is not actually the allocator behavior itself. I suspect that we might have lost LTO on jemalloc and tcache_alloc_small_hard previously got inlined into malloc_default but now no longer is. Possibly updating the host toolchain at the same time so that the versions match will help.

rust-bors · 2026-01-28T05:22:51Z

💔 Test for 917820a failed: CI

ZuseZ4 · 2026-01-28T05:45:47Z

@bors retry

rust-bors · 2026-01-28T11:21:05Z

☀️ Test successful - CI
Approved by: cuviper
Duration: 3h 19m 37s
Pushing 466ea4e to main...

github-actions · 2026-01-28T11:23:40Z

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 e96bb7e (parent) -> 466ea4e (this PR)

Test differences

Show 51 test diffs

Stage 1

[codegen] tests/codegen-llvm/amdgpu-addrspacecast.rs#LLVM21: pass -> ignore (ignored when the LLVM version (22.1.0) is newer than majorversion 21) (J4)
[codegen] tests/codegen-llvm/amdgpu-addrspacecast.rs#LLVM22: ignore (ignored when the LLVM version 21.1.8 is older than 22.0.0) -> pass (J4)
[codegen] tests/codegen-llvm/deduced-param-attrs.rs#LLVM20: ignore (ignored when the LLVM version (21.1.8) is newer than majorversion 20) -> ignore (ignored when the LLVM version (22.1.0) is newer than majorversion 20) (J4)
[codegen] tests/codegen-llvm/enum/enum-discriminant-eq.rs#LLVM20: ignore (ignored when the LLVM version (21.1.8) is newer than majorversion 20) -> ignore (ignored when the LLVM version (22.1.0) is newer than majorversion 20) (J4)
[codegen] tests/codegen-llvm/issues/issue-122600-ptr-discriminant-update.rs#new: ignore (ignored when the LLVM version 21.1.8 is older than 22.0.0) -> pass (J4)
[codegen] tests/codegen-llvm/issues/issue-122600-ptr-discriminant-update.rs#old: pass -> ignore (ignored when the LLVM version (22.1.0) is newer than majorversion 21) (J4)
[codegen] tests/codegen-llvm/simd-intrinsic/simd-intrinsic-generic-gather.rs#LLVM21: pass -> ignore (ignored when the LLVM version (22.1.0) is newer than majorversion 21) (J4)
[codegen] tests/codegen-llvm/simd-intrinsic/simd-intrinsic-generic-gather.rs#LLVM22: ignore (ignored when the LLVM version 21.1.8 is older than 22.0.0) -> pass (J4)
[codegen] tests/codegen-llvm/simd-intrinsic/simd-intrinsic-generic-masked-load.rs#LLVM21: pass -> ignore (ignored when the LLVM version (22.1.0) is newer than majorversion 21) (J4)
[codegen] tests/codegen-llvm/simd-intrinsic/simd-intrinsic-generic-masked-load.rs#LLVM22: ignore (ignored when the LLVM version 21.1.8 is older than 22.0.0) -> pass (J4)
[codegen] tests/codegen-llvm/simd-intrinsic/simd-intrinsic-generic-masked-store.rs#LLVM21: pass -> ignore (ignored when the LLVM version (22.1.0) is newer than majorversion 21) (J4)
[codegen] tests/codegen-llvm/simd-intrinsic/simd-intrinsic-generic-masked-store.rs#LLVM22: ignore (ignored when the LLVM version 21.1.8 is older than 22.0.0) -> pass (J4)
[codegen] tests/codegen-llvm/simd-intrinsic/simd-intrinsic-generic-scatter.rs#LLVM21: pass -> ignore (ignored when the LLVM version (22.1.0) is newer than majorversion 21) (J4)
[codegen] tests/codegen-llvm/simd-intrinsic/simd-intrinsic-generic-scatter.rs#LLVM22: ignore (ignored when the LLVM version 21.1.8 is older than 22.0.0) -> pass (J4)
[codegen] tests/codegen-llvm/vec_pop_push_noop.rs#new: ignore (ignored when the LLVM version 21.1.8 is older than 22.0.0) -> pass (J4)
[codegen] tests/codegen-llvm/vec_pop_push_noop.rs#old: pass -> ignore (ignored when the LLVM version (22.1.0) is newer than majorversion 21) (J4)
[codegen] tests/codegen-llvm/vecdeque_pop_push.rs#new: ignore (ignored when the LLVM version 21.1.8 is older than 22.0.0) -> pass (J4)
[codegen] tests/codegen-llvm/vecdeque_pop_push.rs#old: pass -> ignore (ignored when the LLVM version (22.1.0) is newer than majorversion 21) (J4)
[assembly] tests/assembly-llvm/asm/loongarch-type.rs#loongarch32r: [missing] -> ignore (ignored when the LLVM version 21.1.2 is older than 22.0.0) (J5)
[assembly] tests/assembly-llvm/asm/loongarch-type.rs#loongarch32r: [missing] -> ignore (ignored when the LLVM version 20.1.2 is older than 22.0.0) (J7)
[assembly] tests/assembly-llvm/asm/loongarch-type.rs#loongarch32: pass -> [missing] (J8)
[assembly] tests/assembly-llvm/asm/loongarch-type.rs#loongarch32s: [missing] -> pass (J8)

Stage 2

[assembly] tests/assembly-llvm/asm/loongarch-type.rs#loongarch32r: [missing] -> pass (J0)
[assembly] tests/assembly-llvm/nvptx-safe-naming.rs#LLVM20: ignore (ignored when the LLVM version (21.1.8) is newer than majorversion 20) -> ignore (ignored when the LLVM version (22.1.0) is newer than majorversion 20) (J0)
[codegen] tests/codegen-llvm/amdgpu-addrspacecast.rs#LLVM21: pass -> ignore (ignored when the LLVM version (22.1.0) is newer than majorversion 21) (J0)
[codegen] tests/codegen-llvm/amdgpu-addrspacecast.rs#LLVM22: ignore (ignored when the LLVM version 21.1.8 is older than 22.0.0) -> pass (J0)
[codegen] tests/codegen-llvm/deduced-param-attrs.rs#LLVM20: ignore (ignored when the LLVM version (21.1.8) is newer than majorversion 20) -> ignore (ignored when the LLVM version (22.1.0) is newer than majorversion 20) (J0)
[codegen] tests/codegen-llvm/enum/enum-discriminant-eq.rs#LLVM20: ignore (ignored when the LLVM version (21.1.8) is newer than majorversion 20) -> ignore (ignored when the LLVM version (22.1.0) is newer than majorversion 20) (J0)
[codegen] tests/codegen-llvm/issues/issue-122600-ptr-discriminant-update.rs#new: ignore (ignored when the LLVM version 21.1.8 is older than 22.0.0) -> pass (J0)
[codegen] tests/codegen-llvm/issues/issue-122600-ptr-discriminant-update.rs#old: pass -> ignore (ignored when the LLVM version (22.1.0) is newer than majorversion 21) (J0)
[codegen] tests/codegen-llvm/simd-intrinsic/simd-intrinsic-generic-gather.rs#LLVM21: pass -> ignore (ignored when the LLVM version (22.1.0) is newer than majorversion 21) (J0)
[codegen] tests/codegen-llvm/simd-intrinsic/simd-intrinsic-generic-gather.rs#LLVM22: ignore (ignored when the LLVM version 21.1.8 is older than 22.0.0) -> pass (J0)
[codegen] tests/codegen-llvm/simd-intrinsic/simd-intrinsic-generic-masked-load.rs#LLVM21: pass -> ignore (ignored when the LLVM version (22.1.0) is newer than majorversion 21) (J0)
[codegen] tests/codegen-llvm/simd-intrinsic/simd-intrinsic-generic-masked-load.rs#LLVM22: ignore (ignored when the LLVM version 21.1.8 is older than 22.0.0) -> pass (J0)
[codegen] tests/codegen-llvm/simd-intrinsic/simd-intrinsic-generic-masked-store.rs#LLVM21: pass -> ignore (ignored when the LLVM version (22.1.0) is newer than majorversion 21) (J0)
[codegen] tests/codegen-llvm/simd-intrinsic/simd-intrinsic-generic-masked-store.rs#LLVM22: ignore (ignored when the LLVM version 21.1.8 is older than 22.0.0) -> pass (J0)
[codegen] tests/codegen-llvm/simd-intrinsic/simd-intrinsic-generic-scatter.rs#LLVM21: pass -> ignore (ignored when the LLVM version (22.1.0) is newer than majorversion 21) (J0)
[codegen] tests/codegen-llvm/simd-intrinsic/simd-intrinsic-generic-scatter.rs#LLVM22: ignore (ignored when the LLVM version 21.1.8 is older than 22.0.0) -> pass (J0)
[codegen] tests/codegen-llvm/vec_pop_push_noop.rs#new: ignore (ignored when the LLVM version 21.1.8 is older than 22.0.0) -> pass (J0)
[codegen] tests/codegen-llvm/vec_pop_push_noop.rs#old: pass -> ignore (ignored when the LLVM version (22.1.0) is newer than majorversion 21) (J0)
[codegen] tests/codegen-llvm/vecdeque_pop_push.rs#new: ignore (ignored when the LLVM version 21.1.8 is older than 22.0.0) -> pass (J0)
[codegen] tests/codegen-llvm/vecdeque_pop_push.rs#old: pass -> ignore (ignored when the LLVM version (22.1.0) is newer than majorversion 21) (J0)
[run-make] tests/run-make/compressed-debuginfo-zstd: pass -> ignore (ignored if LLVM wasn't build with zstd for ELF section compression or LLVM is not the default codegen backend) (J1)
[assembly] tests/assembly-llvm/asm/loongarch-type.rs#loongarch32: pass -> [missing] (J2)
[assembly] tests/assembly-llvm/asm/loongarch-type.rs#loongarch32s: [missing] -> pass (J2)
[assembly] tests/assembly-llvm/asm/loongarch-type.rs#loongarch32r: [missing] -> ignore (ignored when the LLVM version 21.1.2 is older than 22.0.0) (J3)
[assembly] tests/assembly-llvm/asm/loongarch-type.rs#loongarch32r: [missing] -> ignore (ignored when the LLVM version 20.1.8 is older than 22.0.0) (J6)
[assembly] tests/assembly-llvm/asm/loongarch-type.rs#loongarch32r: [missing] -> ignore (ignored when the LLVM version 20.1.2 is older than 22.0.0) (J9)
[ui] tests/ui/sanitizer/kcfi-arity-requires-llvm-21-0-0.rs: ignore (ignored when the LLVM version (21.1.8) is newer than majorversion 20) -> ignore (ignored when the LLVM version (22.1.0) is newer than majorversion 20) (J10)

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

Job group index

J0: aarch64-apple, aarch64-gnu, aarch64-msvc-1, arm-android, armhf-gnu, dist-i586-gnu-i586-i686-musl, i686-gnu-1, i686-gnu-nopt-1, i686-msvc-1, test-various, x86_64-gnu, x86_64-gnu-nopt, x86_64-gnu-stable, x86_64-mingw-1, x86_64-msvc-1
J1: x86_64-gnu-nopt
J2: aarch64-apple, aarch64-gnu, aarch64-gnu-llvm-20-1, aarch64-msvc-1, arm-android, armhf-gnu, dist-i586-gnu-i586-i686-musl, i686-gnu-1, i686-gnu-nopt-1, i686-msvc-1, test-various, x86_64-gnu, x86_64-gnu-llvm-20-2, x86_64-gnu-llvm-21-2, x86_64-gnu-nopt, x86_64-gnu-stable, x86_64-mingw-1, x86_64-msvc-1
J3: x86_64-gnu-llvm-21-2
J4: pr-check-2
J5: x86_64-gnu-llvm-21-3
J6: aarch64-gnu-llvm-20-1
J7: x86_64-gnu-llvm-20-3
J8: x86_64-gnu-llvm-20-3, x86_64-gnu-llvm-21-3
J9: x86_64-gnu-llvm-20-2
J10: aarch64-apple, aarch64-gnu, aarch64-msvc-1, arm-android, armhf-gnu, dist-i586-gnu-i586-i686-musl, i686-gnu-1, i686-gnu-nopt-1, i686-msvc-1, test-various, x86_64-gnu, x86_64-gnu-debug, x86_64-gnu-gcc, x86_64-gnu-nopt, x86_64-gnu-stable, x86_64-mingw-1, x86_64-msvc-1

Test dashboard

Run

cargo run --manifest-path src/ci/citool/Cargo.toml -- \
    test-dashboard 466ea4e6c39f8a43727edcc726ca86b499e14d83 --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

pr-check-1: 1701.6s -> 2757.3s (+62.0%)
x86_64-rust-for-linux: 2608.5s -> 4155.2s (+59.3%)
pr-check-2: 2299.3s -> 3415.9s (+48.6%)
x86_64-gnu-tools: 3478.0s -> 4931.2s (+41.8%)
x86_64-gnu-gcc: 3784.3s -> 5209.1s (+37.7%)
x86_64-gnu-miri: 4414.5s -> 5948.0s (+34.7%)
armhf-gnu: 4940.1s -> 6630.2s (+34.2%)
test-various: 7021.9s -> 8888.0s (+26.6%)
dist-arm-linux-musl: 5613.5s -> 6918.5s (+23.2%)
arm-android: 5871.7s -> 7207.8s (+22.8%)

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 · 2026-01-28T12:04:24Z

Finished benchmarking commit (466ea4e): comparison URL.

Overall result: ❌✅ regressions and improvements - please read the text below

Our benchmarks found a performance regression caused by this PR.
This might be an actual regression, but it can also be just noise.

Next Steps:

If the regression was expected or you think it can be justified,
please write a comment with sufficient written justification, and add
@rustbot label: +perf-regression-triaged to it, to mark the regression as triaged.
If you think that you know of a way to resolve the regression, try to create
a new PR with a fix for the regression.
If you do not understand the regression or you think that it is just noise,
you can ask the @rust-lang/wg-compiler-performance working group for help (members of this group
were already notified of this PR).

@rustbot label: +perf-regression
cc @rust-lang/wg-compiler-performance

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)	3.2%	[0.9%, 7.4%]	3
Regressions ❌ (secondary)	2.3%	[0.4%, 6.0%]	3
Improvements ✅ (primary)	-0.7%	[-2.8%, -0.2%]	238
Improvements ✅ (secondary)	-0.9%	[-10.1%, -0.1%]	299
All ❌✅ (primary)	-0.6%	[-2.8%, 7.4%]	241

Max RSS (memory usage)

Results (primary 0.7%, secondary -1.3%)

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

	mean	range	count
Regressions ❌ (primary)	2.9%	[1.4%, 5.4%]	3
Regressions ❌ (secondary)	1.9%	[0.6%, 3.2%]	6
Improvements ✅ (primary)	-2.7%	[-4.0%, -1.3%]	2
Improvements ✅ (secondary)	-3.2%	[-5.0%, -0.6%]	10
All ❌✅ (primary)	0.7%	[-4.0%, 5.4%]	5

Cycles

Results (primary 2.8%, secondary 1.4%)

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

	mean	range	count
Regressions ❌ (primary)	3.7%	[2.0%, 8.5%]	6
Regressions ❌ (secondary)	3.9%	[2.1%, 7.2%]	10
Improvements ✅ (primary)	-3.0%	[-3.0%, -3.0%]	1
Improvements ✅ (secondary)	-4.7%	[-7.0%, -2.0%]	4
All ❌✅ (primary)	2.8%	[-3.0%, 8.5%]	7

Binary size

Results (primary -0.3%, secondary -1.0%)

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

	mean	range	count
Regressions ❌ (primary)	0.1%	[0.1%, 0.1%]	4
Regressions ❌ (secondary)	2.6%	[0.1%, 5.1%]	2
Improvements ✅ (primary)	-0.4%	[-1.4%, -0.1%]	49
Improvements ✅ (secondary)	-1.1%	[-3.8%, -0.0%]	97
All ❌✅ (primary)	-0.3%	[-1.4%, 0.1%]	53

Bootstrap: 470.891s -> 476.499s (1.19%)
Artifact size: 383.44 MiB -> 397.91 MiB (3.77%)

petrochenkov · 2026-01-28T19:39:02Z

Looks like this is causing some segfaults in LoopDeletionPass - #151790.

nnethercote · 2026-01-28T23:03:25Z

About the perf results: the icount results look great, but LLVM updates are big enough that looking at the cycle counts and wall-times is reasonable -- more so than typical PRs that make very small changes. In this case the cycle count and wall-time results are a little bit in the red. We saw a similar thing with the LLVM 21 update. This is different to the previous few LLVM updates before 21 where we saw uniform improvements across icounts/cycles/wall-time.

I'm not sure what to make of this, and it's not going to stop us from updating to LLVM 22. But it seems worth mentioning.

tamird · 2026-01-29T14:55:14Z

@@ -5,7 +5,7 @@ set -ex
 source shared.sh

 # Try to keep the LLVM version here in sync with src/ci/scripts/install-clang.sh


Should this comment be updated? That script is on LLVM 20 and the update cadence seems to be intentionally different.

Yes, we should drop this comment, people are regularly confused by it.

Well we should still try to keep those two close :)

The problem is that this comment, as phrased, doesn't help the reader. What does it mean to try? What are the reasons that these things would drift? Is this one expected to lead or trail? Why?

the8472 · 2026-02-01T11:26:34Z

About the perf results: the icount results look great, but LLVM updates are big enough that looking at the cycle counts and wall-times is reasonable -- more so than typical PRs that make very small changes. In this case the cycle count and wall-time results are a little bit in the red.

Eyeballing the summary charts it only raises above the noise in opt-builds.

cranelift-codegen-0.119.0 opt incr-full wall-time +18% looks very real, the change persists. It's mostly additional time spent in LTO.
Looking at the codegen schedule wall-time was already dominated by the largest codegen-unit before and that one now takes significantly longer.

Pkgsrc changes: * Update version & checksums, and adapt to new libc crate included. Upstream changes relative to 1.94.1: Version 1.95 (2026-04-16) ========================== Language -------- - [Stabilize `if let` guards on match arms] (rust-lang/rust#141295) - [`irrefutable_let_patterns` lint no longer lints on let chains] (rust-lang/rust#146832) - [Support importing path-segment keywords with renaming] (rust-lang/rust#146972) - [Stabilize inline assembly for PowerPC and PowerPC64] (rust-lang/rust#147996) - [const-eval: be more consistent in the behavior of padding during typed copies] (rust-lang/rust#148967) - [Const blocks are no longer evaluated to determine if expressions involving fallible operations can implicitly be constant-promoted.] (rust-lang/rust#150557). Expressions whose ability to implicitly be promoted would depend on the result of a const block are no longer implicitly promoted. - [Make operational semantics of pattern matching independent of crate and module] (rust-lang/rust#150681) Compiler -------- - [Stabilize `--remap-path-scope` for controlling the scoping of how paths get remapped in the resulting binary] (rust-lang/rust#147611) Platform Support ---------------- - [Promote `powerpc64-unknown-linux-musl` to Tier 2 with host tools] (rust-lang/rust#149962) - [Promote `aarch64-apple-tvos` to Tier 2] (rust-lang/rust#152021) - [Promote `aarch64-apple-tvos-sim` to Tier 2] (rust-lang/rust#152021) - [Promote `aarch64-apple-watchos` to Tier 2] (rust-lang/rust#152021) - [Promote `aarch64-apple-watchos-sim` to Tier 2] (rust-lang/rust#152021) - [Promote `aarch64-apple-visionos` to Tier 2] (rust-lang/rust#152021) - [Promote `aarch64-apple-visionos-sim` to Tier 2] (rust-lang/rust#152021) Refer to Rust's [platform support page][platform-support-doc] for more information on Rust's tiered platform support. https://doc.rust-lang.org/rustc/platform-support.html Libraries --------- - [`thread::scope`: document how join interacts with TLS destructors] (rust-lang/rust#149482) - [Speed up `str::contains` on aarch64 targets with `neon` target feature enabled by default] (rust-lang/rust#152176) Stabilized APIs --------------- - [`MaybeUninit<[T; N]>: From<[MaybeUninit<T>; N]>`] (https://doc.rust-lang.org/stable/std/mem/union.MaybeUninit.html#impl-From%3CMaybeUninit%3C%5BT;+N%5D%3E%3E-for-%5BMaybeUninit%3CT%3E;+N%5D) - [`MaybeUninit<[T; N]>: AsRef<[MaybeUninit<T>; N]>`] (https://doc.rust-lang.org/stable/std/mem/union.MaybeUninit.html#impl-AsRef%3C%5BMaybeUninit%3CT%3E;+N%5D%3E-for-MaybeUninit%3C%5BT;+N%5D%3E) - [`MaybeUninit<[T; N]>: AsRef<[MaybeUninit<T>]>`] (https://doc.rust-lang.org/stable/std/mem/union.MaybeUninit.html#impl-AsRef%3C%5BMaybeUninit%3CT%3E%5D%3E-for-MaybeUninit%3C%5BT;+N%5D%3E) - [`MaybeUninit<[T; N]>: AsMut<[MaybeUninit<T>; N]>`] (https://doc.rust-lang.org/beta/std/mem/union.MaybeUninit.html#impl-AsMut%3C%5BMaybeUninit%3CT%3E;+N%5D%3E-for-MaybeUninit%3C%5BT;+N%5D%3E) - [`MaybeUninit<[T; N]>: AsMut<[MaybeUninit<T>]>`] (https://doc.rust-lang.org/stable/std/mem/union.MaybeUninit.html#impl-AsMut%3C%5BMaybeUninit%3CT%3E%5D%3E-for-MaybeUninit%3C%5BT;+N%5D%3E) - [`[MaybeUninit<T>; N]: From<MaybeUninit<[T; N]>>`] (https://doc.rust-lang.org/stable/std/mem/union.MaybeUninit.html#impl-From%3C%5BMaybeUninit%3CT%3E;+N%5D%3E-for-MaybeUninit%3C%5BT;+N%5D%3E) - [`Cell<[T; N]>: AsRef<[Cell<T>; N]>`] (https://doc.rust-lang.org/stable/std/cell/struct.Cell.html#impl-AsRef%3C%5BCell%3CT%3E;+N%5D%3E-for-Cell%3C%5BT;+N%5D%3E) - [`Cell<[T; N]>: AsRef<[Cell<T>]>`] (https://doc.rust-lang.org/stable/std/cell/struct.Cell.html#impl-AsRef%3C%5BCell%3CT%3E%5D%3E-for-Cell%3C%5BT;+N%5D%3E) - [`Cell<[T]>: AsRef<[Cell<T>]>`] (https://doc.rust-lang.org/stable/std/cell/struct.Cell.html#impl-AsRef%3C%5BCell%3CT%3E%5D%3E-for-Cell%3C%5BT%5D%3E) - [`bool: TryFrom<{integer}>`] (https://doc.rust-lang.org/stable/std/primitive.bool.html#impl-TryFrom%3Cu128%3E-for-bool) - [`AtomicPtr::update`] (https://doc.rust-lang.org/stable/std/sync/atomic/struct.AtomicPtr.html#method.update) - [`AtomicPtr::try_update`] (https://doc.rust-lang.org/stable/std/sync/atomic/struct.AtomicPtr.html#method.try_update) - [`AtomicBool::update`] (https://doc.rust-lang.org/stable/std/sync/atomic/struct.AtomicBool.html#method.update) - [`AtomicBool::try_update`] (https://doc.rust-lang.org/stable/std/sync/atomic/struct.AtomicBool.html#method.try_update) - [`AtomicIn::update`] (https://doc.rust-lang.org/stable/std/sync/atomic/struct.AtomicIsize.html#method.update) - [`AtomicIn::try_update`] (https://doc.rust-lang.org/stable/std/sync/atomic/struct.AtomicIsize.html#method.try_update) - [`AtomicUn::update`] (https://doc.rust-lang.org/stable/std/sync/atomic/struct.AtomicUsize.html#method.update) - [`AtomicUn::try_update`] (https://doc.rust-lang.org/stable/std/sync/atomic/struct.AtomicUsize.html#method.try_update) - [`cfg_select!`] (https://doc.rust-lang.org/stable/std/macro.cfg_select.html) - [`mod core::range`] (https://doc.rust-lang.org/stable/core/range/index.html) - [`core::range::RangeInclusive`] (https://doc.rust-lang.org/stable/core/range/struct.RangeInclusive.html) - [`core::range::RangeInclusiveIter`] (https://doc.rust-lang.org/stable/core/range/struct.RangeInclusiveIter.html) - [`core::hint::cold_path`] (https://doc.rust-lang.org/stable/core/hint/fn.cold_path.html) - [`<*const T>::as_ref_unchecked`] (https://doc.rust-lang.org/stable/std/primitive.pointer.html#method.as_ref_unchecked) - [`<*mut T>::as_ref_unchecked`] (https://doc.rust-lang.org/stable/std/primitive.pointer.html#method.as_ref_unchecked-1) - [`<*mut T>::as_mut_unchecked`] (https://doc.rust-lang.org/stable/std/primitive.pointer.html#method.as_mut_unchecked) These previously stable APIs are now stable in const contexts: - [`fmt::from_fn`] (https://doc.rust-lang.org/stable/std/fmt/fn.from_fn.html) - [`ControlFlow::is_break`] (https://doc.rust-lang.org/stable/core/ops/enum.ControlFlow.html#method.is_break) - [`ControlFlow::is_continue`] (https://doc.rust-lang.org/stable/core/ops/enum.ControlFlow.html#method.is_continue) Cargo ----- - [docs(report): enhance man pages for `cargo report *`] (rust-lang/cargo#16430) Rustdoc ----- - [In search results, rank unstable items lower] (rust-lang/rust#149460) - [Add new "hide deprecated items" setting in rustdoc] (rust-lang/rust#151091) Compatibility Notes ------------------- - [Array coercions may now result in less inference constraints than before] (rust-lang/rust#140283) - Importing `$crate` without renaming, i.e. `use $crate::{self};`, is now no longer permitted due to stricter error checking for `self` imports. - [const-eval: be more consistent in the behavior of padding during typed copies.] (rust-lang/rust#148967) In very rare cases, this may cause compilation errors due to bytes from parts of a pointer ending up in the padding bytes of a `const` or `static`. - [A future-incompatibility warning lint `ambiguous_glob_imported_traits` is now reported when using an ambiguously glob imported trait] (rust-lang/rust#149058) - [Check lifetime bounds of types mentioning only type parameters] (rust-lang/rust#149389) - [Report more visibility-related ambiguous import errors] (rust-lang/rust#149596) - [Deprecate `Eq::assert_receiver_is_total_eq` and emit future compatibility warnings on manual impls] (rust-lang/rust#149978) - [powerpc64: Use the ELF ABI version set in target spec instead of guessing] (rust-lang/rust#150468) (fixes the ELF ABI used by the OpenBSD target) - Matching on a `#[non_exhaustive]` enum [now reads the discriminant, even if the enum has only one variant] (rust-lang/rust#150681). This can cause closures to capture values that they previously wouldn't. - `mut ref` and `mut ref mut` patterns, part of the unstable [Match Ergonomics 2024 RFC] (rust-lang/rust#123076), were accidentally allowed on stable within struct pattern field shorthand. These patterns are now correctly feature-gated as unstable in this position. - [Add future-compatibility warning for derive helper attributes which conflict with built-in attributes] (rust-lang/rust#151152) - [JSON target specs] (https://doc.rust-lang.org/rustc/targets/custom.html) have been destabilized and now require `-Z unstable-options` to use. Previously, they could not be used without the standard library, which has no stable build mechanism. In preparation for the `build-std` project adding that support, JSON target specs are being proactively gated to ensure they remain unstable even if `build-std` is stabilized. Cargo now includes the `-Z json-target-spec` CLI flag to automatically pass `-Z unstable-options` to the compiler when needed. See [#150151] (rust-lang/rust#150151), [#151534] (rust-lang/rust#150151), and [rust-lang/cargo#16557] (rust-lang/cargo#16557). - [The arguments of `#[feature]` attributes on invalid targets are now checked] (rust-lang/rust#153764) Internal Changes ---------------- These changes do not affect any public interfaces of Rust, but they represent significant improvements to the performance or internals of rustc and related tools. - [Update to LLVM 22](rust-lang/rust#150722)

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rust-bors bot added a commit that referenced this pull request Jan 6, 2026

Auto merge of #150722 - nikic:llvm-22, r=<try>

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Update to LLVM 22

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rustbot added perf-regression Performance regression. and removed S-waiting-on-perf Status: Waiting on a perf run to be completed. labels Jan 6, 2026

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Kobzol mentioned this pull request Jan 6, 2026

Only require try permissions for marking a PR as rollup rust-lang/bors#553

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nikic force-pushed the llvm-22 branch from b0ff5bb to 78019a6 Compare January 6, 2026 15:46

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nikic force-pushed the llvm-22 branch from 78019a6 to aafd9df Compare January 8, 2026 15:01

rustbot added A-CI Area: Our Github Actions CI A-testsuite Area: The testsuite used to check the correctness of rustc T-infra Relevant to the infrastructure team, which will review and decide on the PR/issue. labels Jan 8, 2026

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rust-bors bot merged commit 466ea4e into rust-lang:main Jan 28, 2026
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rust-bors bot mentioned this pull request Jan 28, 2026

feat(build): centralize LLVM_VERSION #142786

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tamird mentioned this pull request Jan 29, 2026

ci: install autopoint for aya integration tests aya-rs/bpf-linker#340

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roblabla mentioned this pull request Jan 29, 2026

SIGSEGV during stage1 compilation of proc_macro for i686-win7-windows-msvc #151832

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eggyal mentioned this pull request Feb 4, 2026

panic_bounds_check isn't optimized away in impl fmt::Display for integers (regression between 1.92 and 1.93) #152061

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smoelius mentioned this pull request Feb 7, 2026

Pin to nightly-2026-01-28 rust-fuzz/afl.rs#698

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theemathas mentioned this pull request Mar 14, 2026

1.95 beta regression: "displacement ... is not within [-2147483648, 2147483647]" #153852

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mati865 mentioned this pull request Mar 15, 2026

Significant compilation time regression starting in v1.95.0-nightly (bevy) #153910

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jyn514 mentioned this pull request Mar 16, 2026

Updated dates rust-lang/rustc-dev-guide#2796

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Draft release notes for 1.95 #154711

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BoxyUwU added the relnotes Marks issues that should be documented in the release notes of the next release. label Apr 11, 2026

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Tracking issue for release notes of #150722: Update to LLVM 22 #155158

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blackms mentioned this pull request Apr 14, 2026

Use unchecked indexing in integer _fmt_inner to keep bounds checks elided #155289

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xtqqczze mentioned this pull request Apr 16, 2026

clippy: fix rust 1.95 lints uutils/coreutils#11861

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		@@ -5,7 +5,7 @@ set -ex
		source shared.sh

		# Try to keep the LLVM version here in sync with src/ci/scripts/install-clang.sh

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Overall result: ❌✅ regressions and improvements - please read the text below

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Overall result: ❌✅ regressions and improvements - please read the text below

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nikic commented Jan 6, 2026 •

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