Update to LLVM 21 #143684

nikic · 2025-07-09T12:41:26Z

Timeline: LLVM 21.1.0 is scheduled to release on Aug 26th. Rust 1.90 branches on Aug 1st and releases September 18.

Depends on:

r? @ghost

rustbot · 2025-07-09T12:41:31Z

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

nikic · 2025-07-09T12:46:44Z

@bors2 try @rust-timer queue

Update to LLVM 21 r? `@ghost`

rust-bors · 2025-07-09T12:46:48Z

⌛ Trying commit ebb63b9 with merge c3e645b…

To cancel the try build, run the command @bors2 try cancel.

rust-bors · 2025-07-09T14:22:01Z

💔 Test failed

CI ❌

nikic · 2025-07-09T14:30:42Z

Noooo, a crash while profiling with the bolt instrumentation.

    process didn't exit successfully: `/tmp/tmp-multistage/opt-artifacts/rustc-perf/target/debug/rustc-fake --crate-name regex_automata --edition=2021 /cargo/registry/src/index.crates.io-1949cf8c6b5b557f/regex-automata-0.4.9/src/lib.rs --error-format=json --json=diagnostic-rendered-ansi,artifacts,future-incompat --crate-type lib --emit=dep-info,metadata,link -C opt-level=3 -C embed-bitcode=no --cfg 'feature="alloc"' --cfg 'feature="dfa-onepass"' --cfg 'feature="dfa-search"' --cfg 'feature="hybrid"' --cfg 'feature="meta"' --cfg 'feature="nfa"' --cfg 'feature="nfa-backtrack"' --cfg 'feature="nfa-pikevm"' --cfg 'feature="nfa-thompson"' --cfg 'feature="perf"' --cfg 'feature="perf-inline"' --cfg 'feature="perf-literal"' --cfg 'feature="perf-literal-multisubstring"' --cfg 'feature="perf-literal-substring"' --cfg 'feature="std"' --cfg 'feature="syntax"' --cfg 'feature="unicode"' --cfg 'feature="unicode-age"' --cfg 'feature="unicode-bool"' --cfg 'feature="unicode-case"' --cfg 'feature="unicode-gencat"' --cfg 'feature="unicode-perl"' --cfg 'feature="unicode-script"' --cfg 'feature="unicode-segment"' --cfg 'feature="unicode-word-boundary"' --check-cfg 'cfg(docsrs,test)' --check-cfg 'cfg(feature, values("alloc", "default", "dfa", "dfa-build", "dfa-onepass", "dfa-search", "hybrid", "internal-instrument", "internal-instrument-pikevm", "logging", "meta", "nfa", "nfa-backtrack", "nfa-pikevm", "nfa-thompson", "perf", "perf-inline", "perf-literal", "perf-literal-multisubstring", "perf-literal-substring", "std", "syntax", "unicode", "unicode-age", "unicode-bool", "unicode-case", "unicode-gencat", "unicode-perl", "unicode-script", "unicode-segment", "unicode-word-boundary"))' -C metadata=29004f3d2c23a6dc -C extra-filename=-acaa9aabb4aa769d --out-dir /tmp/.tmpSoAMdr/target/release/deps -C linker=clang -C strip=debuginfo -L dependency=/tmp/.tmpSoAMdr/target/release/deps --extern aho_corasick=/tmp/.tmpSoAMdr/target/release/deps/libaho_corasick-f3f82c9a60cf08f9.rmeta --extern memchr=/tmp/.tmpSoAMdr/target/release/deps/libmemchr-e5f42c55eae6f759.rmeta --extern regex_syntax=/tmp/.tmpSoAMdr/target/release/deps/libregex_syntax-7bce46b340cd2bfa.rmeta --cap-lints allow` (signal: 11, SIGSEGV: invalid memory reference)

Kobzol · 2025-07-09T15:31:03Z

Noooo, a crash while profiling with the bolt instrumentation.

    process didn't exit successfully: `/tmp/tmp-multistage/opt-artifacts/rustc-perf/target/debug/rustc-fake --crate-name regex_automata --edition=2021 /cargo/registry/src/index.crates.io-1949cf8c6b5b557f/regex-automata-0.4.9/src/lib.rs --error-format=json --json=diagnostic-rendered-ansi,artifacts,future-incompat --crate-type lib --emit=dep-info,metadata,link -C opt-level=3 -C embed-bitcode=no --cfg 'feature="alloc"' --cfg 'feature="dfa-onepass"' --cfg 'feature="dfa-search"' --cfg 'feature="hybrid"' --cfg 'feature="meta"' --cfg 'feature="nfa"' --cfg 'feature="nfa-backtrack"' --cfg 'feature="nfa-pikevm"' --cfg 'feature="nfa-thompson"' --cfg 'feature="perf"' --cfg 'feature="perf-inline"' --cfg 'feature="perf-literal"' --cfg 'feature="perf-literal-multisubstring"' --cfg 'feature="perf-literal-substring"' --cfg 'feature="std"' --cfg 'feature="syntax"' --cfg 'feature="unicode"' --cfg 'feature="unicode-age"' --cfg 'feature="unicode-bool"' --cfg 'feature="unicode-case"' --cfg 'feature="unicode-gencat"' --cfg 'feature="unicode-perl"' --cfg 'feature="unicode-script"' --cfg 'feature="unicode-segment"' --cfg 'feature="unicode-word-boundary"' --check-cfg 'cfg(docsrs,test)' --check-cfg 'cfg(feature, values("alloc", "default", "dfa", "dfa-build", "dfa-onepass", "dfa-search", "hybrid", "internal-instrument", "internal-instrument-pikevm", "logging", "meta", "nfa", "nfa-backtrack", "nfa-pikevm", "nfa-thompson", "perf", "perf-inline", "perf-literal", "perf-literal-multisubstring", "perf-literal-substring", "std", "syntax", "unicode", "unicode-age", "unicode-bool", "unicode-case", "unicode-gencat", "unicode-perl", "unicode-script", "unicode-segment", "unicode-word-boundary"))' -C metadata=29004f3d2c23a6dc -C extra-filename=-acaa9aabb4aa769d --out-dir /tmp/.tmpSoAMdr/target/release/deps -C linker=clang -C strip=debuginfo -L dependency=/tmp/.tmpSoAMdr/target/release/deps --extern aho_corasick=/tmp/.tmpSoAMdr/target/release/deps/libaho_corasick-f3f82c9a60cf08f9.rmeta --extern memchr=/tmp/.tmpSoAMdr/target/release/deps/libmemchr-e5f42c55eae6f759.rmeta --extern regex_syntax=/tmp/.tmpSoAMdr/target/release/deps/libregex_syntax-7bce46b340cd2bfa.rmeta --cap-lints allow` (signal: 11, SIGSEGV: invalid memory reference)

Oh no, the day has finally come 😆

nikic · 2025-07-09T16:44:32Z

llvm/llvm-project#147781 for pr-check-1 assertion failure.

bors · 2025-07-10T05:52:36Z

☔ The latest upstream changes (presumably #143703) made this pull request unmergeable. Please resolve the merge conflicts.

nikic · 2025-07-10T10:33:49Z

llvm/llvm-project#147935 for armhf-gnu test failure.

nikic · 2025-07-10T12:56:26Z

llvm/llvm-project#139443 for musl build failure.

nikic · 2025-07-11T10:54:39Z

llvm/llvm-project#148207 for x86_64-gnu-nopt assertion failure.

rustbot · 2025-07-14T08:32:07Z

⚠️ Warning ⚠️

Some commits in this PR modify submodules.

nikic · 2025-07-14T12:17:33Z

llvm/llvm-project#148607 for the brand new x86_64-gnu-miri build failure...

bors · 2025-07-14T13:25:21Z

☔ The latest upstream changes (presumably #143873) made this pull request unmergeable. Please resolve the merge conflicts.

nikic · 2025-07-15T16:44:46Z

@bors2 try

I was unable to reproduce the bolt issue locally. Fingers crossed that I just hit a bad commit or something.

Update to LLVM 21 Depends on: * [x] llvm/llvm-project#147781 * [x] llvm/llvm-project#147935 * [x] llvm/llvm-project#139443 * [x] llvm/llvm-project#148207 * [x] llvm/llvm-project#148607 r? `@ghost`

rust-bors · 2025-07-15T16:44:51Z

⌛ Trying commit b0b9a3c with merge cd80bb6…

To cancel the try build, run the command @bors2 try cancel.

Kobzol · 2025-07-16T16:26:20Z

~~This entire city must be~~ Purged.

rust-bors · 2025-07-16T17:06:18Z

☀️ Try build successful (CI)
Build commit: f4ce95e (f4ce95eedb14d3c068f7e3f04c61dd62257688a1, parent: f21fbac535ab2c3bc50db20547f4d48477357103)

nikic · 2025-07-16T17:12:04Z

@bors2 try jobs=x86_64-mingw-1,x86_64-mingw-2,dist-i686-mingw,dist-x86_64-mingw,aarch64-msvc-1,aarch64-msvc-2,dist-aarch64-msvc

rust-bors · 2025-07-16T17:12:09Z

⌛ Trying commit 5beee45 with merge ea49c99…

To cancel the try build, run the command @bors2 try cancel.

Update to LLVM 21 Depends on: * [x] llvm/llvm-project#147781 * [x] llvm/llvm-project#147935 * [x] llvm/llvm-project#139443 * [x] llvm/llvm-project#148207 * [x] llvm/llvm-project#148607 * [ ] llvm/llvm-project#149046 * [ ] llvm/llvm-project#149097 r? `@ghost` try-job: x86_64-mingw-1 try-job: x86_64-mingw-2 try-job: dist-i686-mingw try-job: dist-x86_64-mingw try-job: aarch64-msvc-1 try-job: aarch64-msvc-2 try-job: dist-aarch64-msvc

rust-bors · 2025-07-16T21:36:08Z

☀️ Try build successful (CI)
Build commit: ea49c99 (ea49c99ab4204207c1555639677f941e3db7d9f4, parent: 1c6de215099bbe33668de762f9591187f6c25eef)

The presence of `@add-core-stubs` indicates that this was already intended.

nikic · 2025-07-17T07:46:27Z

@bors2 try jobs=x86_64-msvc-1,x86_64-msvc-2,i686-msvc-1,i686-msvc-2,x86_64-msvc-ext1,x86_64-msvc-ext2,x86_64-msvc-ext3,dist-x86_64-msvc,dist-i686-msvc,dist-x86_64-msvc-alt

Update to LLVM 21 Depends on: * [x] llvm/llvm-project#147781 * [x] llvm/llvm-project#147935 * [x] llvm/llvm-project#139443 * [x] llvm/llvm-project#148207 * [x] llvm/llvm-project#148607 * [x] llvm/llvm-project#149046 * [ ] llvm/llvm-project#149097 r? `@ghost` try-job: x86_64-msvc-1 try-job: x86_64-msvc-2 try-job: i686-msvc-1 try-job: i686-msvc-2 try-job: x86_64-msvc-ext1 try-job: x86_64-msvc-ext2 try-job: x86_64-msvc-ext3 try-job: dist-x86_64-msvc try-job: dist-i686-msvc try-job: dist-x86_64-msvc-alt

rust-bors · 2025-07-17T07:46:31Z

⌛ Trying commit cd31920 with merge 84911f9…

To cancel the try build, run the command @bors2 try cancel.

rust-bors · 2025-07-17T11:27:25Z

💔 Test failed

CI ❌

nikic · 2025-07-17T12:17:59Z

Looks like x86_64-msvc-1 ran out of disk space :(

In the hope that this may fix the bolt issue.

nikic · 2025-07-17T12:28:23Z

@bors2 try

Testing whether updating the host toolchain fixes the bolt issue, though I don't have high hopes...

rust-bors · 2025-07-17T12:28:28Z

⌛ Trying commit ab7d9df with merge 3ad929f…

To cancel the try build, run the command @bors2 try cancel.

Update to LLVM 21 Depends on: * [x] llvm/llvm-project#147781 * [x] llvm/llvm-project#147935 * [x] llvm/llvm-project#139443 * [x] llvm/llvm-project#148207 * [x] llvm/llvm-project#148607 * [x] llvm/llvm-project#149046 * [ ] llvm/llvm-project#149097 r? `@ghost`

rust-bors · 2025-07-17T15:59:11Z

☀️ Try build successful (CI)
Build commit: 3ad929f (3ad929f623d4cda65ae0e0dcdb154816042509ea, parent: 8c12d76304fcceaeaad0d67209e5727e94f5f2b8)

Kobzol · 2025-07-17T16:03:15Z

Since it went through, we might as well:

@rust-timer build 3ad929f

rust-timer · 2025-07-17T17:59:07Z

Finished benchmarking commit (3ad929f): 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)	0.6%	[0.5%, 0.7%]	2
Regressions ❌ (secondary)	2.1%	[2.0%, 2.2%]	3
Improvements ✅ (primary)	-1.3%	[-23.4%, -0.2%]	254
Improvements ✅ (secondary)	-2.6%	[-19.3%, -0.2%]	290
All ❌✅ (primary)	-1.3%	[-23.4%, 0.7%]	256

Max RSS (memory usage)

Results (primary -2.6%, secondary 2.6%)

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

	mean	range	count
Regressions ❌ (primary)	2.6%	[1.2%, 4.6%]	4
Regressions ❌ (secondary)	4.0%	[0.9%, 7.6%]	13
Improvements ✅ (primary)	-4.2%	[-7.6%, -1.3%]	13
Improvements ✅ (secondary)	-3.8%	[-5.4%, -1.7%]	3
All ❌✅ (primary)	-2.6%	[-7.6%, 4.6%]	17

Cycles

Results (primary 0.3%, secondary -3.8%)

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

	mean	range	count
Regressions ❌ (primary)	1.9%	[1.9%, 1.9%]	1
Regressions ❌ (secondary)	-	-	0
Improvements ✅ (primary)	-1.3%	[-1.3%, -1.3%]	1
Improvements ✅ (secondary)	-3.8%	[-12.4%, -1.7%]	36
All ❌✅ (primary)	0.3%	[-1.3%, 1.9%]	2

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)	0.1%	[0.0%, 0.2%]	30
Regressions ❌ (secondary)	0.1%	[0.0%, 0.2%]	14
Improvements ✅ (primary)	-0.2%	[-0.4%, -0.0%]	20
Improvements ✅ (secondary)	-0.2%	[-1.0%, -0.1%]	41
All ❌✅ (primary)	-0.0%	[-0.4%, 0.2%]	50

Bootstrap: 463.461s -> 459.088s (-0.94%)
Artifact size: 374.76 MiB -> 374.77 MiB (0.00%)

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rust-bors bot added a commit that referenced this pull request Jul 9, 2025

Auto merge of #143684 - nikic:llvm-21, r=<try>

c3e645b

Update to LLVM 21 r? `@ghost`

rustbot added the S-waiting-on-perf Status: Waiting on a perf run to be completed. label Jul 9, 2025

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nikic force-pushed the llvm-21 branch from ebb63b9 to 0d6d6b0 Compare July 9, 2025 13:33

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nikic force-pushed the llvm-21 branch from 0d6d6b0 to 4ce4c54 Compare July 10, 2025 14:42

nikic force-pushed the llvm-21 branch from f913490 to 94ca2b6 Compare July 14, 2025 08:37

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nikic force-pushed the llvm-21 branch from 94ca2b6 to b0b9a3c Compare July 15, 2025 08:14

nikic added 4 commits July 17, 2025 09:41

Update to LLVM 21

ddc57e5

Update AMDGPU data layout

39eb20c

Pass wasm exception model to TargetOptions

114a707

Make emit-arity-indicator.rs a no_core test

cd31920

The presence of `@add-core-stubs` indicates that this was already intended.

nikic force-pushed the llvm-21 branch from 5beee45 to cd31920 Compare July 17, 2025 07:41

Try updating host toolchain

ab7d9df

In the hope that this may fix the bolt issue.

rustbot added 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 Jul 17, 2025

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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 Jul 17, 2025

This was referenced Jul 18, 2025

Fixes for LLVM 21 #144116

Open

Update dist-x86_64-linux host toolchain to LLVM 21 #144117

Closed

Update to LLVM 21 #143684

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Update to LLVM 21 #143684

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rust-timer commented Jul 17, 2025

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

Instruction count

Max RSS (memory usage)

Cycles

Binary size

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