Rollup of 11 pull requests by JonathanBrouwer · Pull Request #163970 · rust-lang/rust

JonathanBrouwer · 2026-10-08T06:55:46Z

Successful merges:

codegen: tell LLVM that the discriminant is a power of two #162741 (codegen: tell LLVM that the discriminant is a power of two)
Split PassMode::IndirectUnsized out of PassMode::Indirect #162758 (Split PassMode::IndirectUnsized out of PassMode::Indirect)
Move loop_hint_attrs from Terminator into TerminatorKind::Goto #163931 (Move loop_hint_attrs from Terminator into TerminatorKind::Goto)
autodiff: fix sysroot candidates in libEnzyme not found error #163028 (autodiff: fix sysroot candidates in libEnzyme not found error)
abby DSL: sanity checks on forall where clauses #163257 (abby DSL: sanity checks on forall where clauses)
[rustdoc] Fix more incoherent_impl linking #163841 ([rustdoc] Fix more incoherent_impl linking)
Update Enzyme submodule #163908 (Update Enzyme submodule)
Use BasicBlock::start_location and Location::START #163935 (Use BasicBlock::start_location and Location::START)
disable next-solver with higher-ranked-assumptions #163949 (disable next-solver with higher-ranked-assumptions)
relax_elf_relocations is x86-only #163951 (relax_elf_relocations is x86-only)
Remove needs-triage label from relnotes issues #163968 (Remove needs-triage label from relnotes issues)

This prevents nonsensical combinations like unsized+on_stack and forces all users to explicitly handle the difference between sized and unsized arguments. In a couple of places unsized arguments were handled incorrectly if they would ever manage to reach that code.

This will make it easier to move them in a subsequent commit, since `UnrollAttr` implements `PartialEq`. If, in the future, we add more kinds of loop hints, this can become a small enum wrapping only those attr types.

We should not disable the pattern in MatchBranchSimplification. The two forms exhaustive match and cast are equivalent, but the cast is better represented in MIR: no branches, only one statement. AFAIK, LLVM does not handle multiple disjoint intervals well. As an workaround, the patch emits `assume(ctpop(val) == 1)` to tell LLVM that the discriminant is a power of two.

Only the `Goto` variant uses `loop_hint_attrs`, so other variants shouldn't pay the cost. This shrinks `Terminator` and thus `BasicBlockData` by 8 bytes, and also simplifies many users of `Terminator`. Every byte saved from `BasicBlockData` makes a big difference in max-rss. For aws-sdk-ec2 full check, this saves 34.1 MiB (~0.62% of its peak RSS) Add a `TerminatorKind::goto` helper function for convenient construction with a target and no hints. With that helper available, most of this commit is simple, straightforward, mechanical translations of construction or pattern matching. The only notable changes are: - `compiler/rustc_codegen_ssa/src/mir/block.rs` actually uses the moved hints. - `compiler/rustc_middle/src/mir/mod.rs` updates the size assertions. - `compiler/rustc_mir_build/src/builder/cfg.rs` adds/updates helpers. - `compiler/rustc_mir_build/src/builder/expr/into.rs` has the one place that creates a `Goto` with non-empty hints.

… r=saethlin codegen: tell LLVM that the discriminant is a power of two Fixes rust-lang#162513. We should not disable the pattern in MatchBranchSimplification. The two forms exhaustive match and cast are equivalent, but the cast is better represented in MIR: no branches, only one statement. AFAIK, LLVM does not handle multiple disjoint intervals well. As an workaround, the patch emits `assume(ctpop(val) == 1)` to tell LLVM that the discriminant is a power of two. LLM disclosure: search the codebase and fix grammer.

… r=beetrees Split PassMode::IndirectUnsized out of PassMode::Indirect This prevents nonsensical combinations like unsized+on_stack and forces all users to explicitly handle the difference between sized and unsized arguments. In a couple of places unsized arguments were handled incorrectly if they would ever manage to reach that code.

…n-goto, r=saethlin Move `loop_hint_attrs` from `Terminator` into `TerminatorKind::Goto` Only the `Goto` variant uses `loop_hint_attrs`, so other variants shouldn't pay the cost. This shrinks `Terminator` and thus `BasicBlockData` by 8 bytes, and also simplifies many users of `Terminator`. Every byte saved from `BasicBlockData` makes a big difference in max-rss. For aws-sdk-ec2 full check, this saves 34.1 MiB (~0.62% of its peak RSS) Add a `TerminatorKind::goto` helper function for convenient construction with a target and no hints. With that helper available, most of this commit is simple, straightforward, mechanical translations of construction or pattern matching. The only notable changes are: - `compiler/rustc_codegen_ssa/src/mir/block.rs` actually uses the moved hints. - `compiler/rustc_middle/src/mir/mod.rs` updates the size assertions. - `compiler/rustc_mir_build/src/builder/cfg.rs` adds/updates helpers. - `compiler/rustc_mir_build/src/builder/expr/into.rs` has the one place that creates a `Goto` with non-empty hints. --- I have several more potential improvements to basic block sizes, but this one was an easy starting point.

@ZuseZ4

…useZ4 autodiff: fix sysroot candidates in libEnzyme not found error fix: rust-lang#160335 (comment) Before ```shell RUSTFLAGS="-Zautodiff=Enable" cargo +enzyme run info: `cargo` is unavailable for the active toolchain info: falling back to "/home/gh-sgasho/.rustup/toolchains/nightly-x86_64-unknown-linux-gnu/bin/cargo" error: failed to run `rustc` to learn about target-specific information Caused by: process didn't exit successfully: `/home/gh-sgasho/.rustup/toolchains/enzyme/bin/rustc - --crate-name ___ --print=file-names -Zautodiff=Enable --crate-type bin --crate-type rlib --crate-type dylib --crate-type cdylib --crate-type staticlib --crate-type proc-macro --print=split-debuginfo --print=crate-name --print=cfg -Wwarnings` (exit status: 1) --- stderr error: autodiff backend not found in the sysroot: failed to find a `libEnzyme-23` folder in the sysroot candidates: * /home/gh-sgasho/rust-worktrees/enzyme-wrapper-cleanup/build/x86_64-unknown-linux-gnu/stage1/lib | = note: it will be distributed via rustup in the future ``` After: points out the right candidate dir ```shell RUSTFLAGS="-Zautodiff=Enable" cargo +enzyme run --release info: `cargo` is unavailable for the active toolchain info: falling back to "/home/gh-sgasho/.rustup/toolchains/nightly-x86_64-unknown-linux-gnu/bin/cargo" error: failed to run `rustc` to learn about target-specific information Caused by: process didn't exit successfully: `/home/gh-sgasho/.rustup/toolchains/enzyme/bin/rustc - --crate-name ___ --print=file-names -Zautodiff=Enable --crate-type bin --crate-type rlib --crate-type dylib --crate-type cdylib --crate-type staticlib --crate-type proc-macro --print=split-debuginfo --print=crate-name --print=cfg -Wwarnings` (exit status: 1) --- stderr error: autodiff backend not found in the sysroot: failed to find a `libEnzyme-23.so` in the sysroot candidates: * /home/gh-sgasho/rust-worktrees/enzyme-wrapper-cleanup/build/x86_64-unknown-linux-gnu/stage1/lib/rustlib/x86_64-unknown-linux-gnu/lib | = note: it will be distributed via rustup in the future ``` I also verified that sample autodiff code ran successfully using local build, without breaking anything. r? @ZuseZ4

@BoxyUwU

…r=BoxyUwU,bit-aloo abby DSL: sanity checks on forall where clauses fixes rust-lang/project-assumptions-on-binders#43 took the opportunity to clean up a bit too, so the diff is a bit bigger than it strictly needs to be this PR enforces that the LHS of forall where clauses must be a placeholder (or toplevel param), an alias, or a lifetime also, after review, this PR now enforces that all implied bounds in where clauses are also explicitly present as well, enforcing that there's no sneaky bounds going on r? @BoxyUwU

@Urgau

…Urgau [rustdoc] Fix more `incoherent_impl` linking Hopefully last fix for rust-lang#162808. We force the correct crate to be linked when generating the external location based on the `DefId` crate. I'm actually surprised it wasn't an issue before. Oh well. r? @Urgau

@wsmoses

…r=ZuseZ4 Update Enzyme submodule r? ZuseZ4 cc @wsmoses @bors try jobs=dist-x86_64-linux,optional-test-x86_64-gnu-autodiff

Use BasicBlock::start_location and Location::START Construct special MIR locations concisely.

@lqd

…t, r=lqd disable next-solver with higher-ranked-assumptions that's nicer than needing to update all the `[assumptions]` ui tests I think r? @lqd or @BoxyUwU

@bjorn3

…wesleywiser relax_elf_relocations is x86-only The flag ends up here https://github.com/rust-lang/rust/blob/8d1a76430406c877b35d0b627e7f796dcf0dfeca/compiler/rustc_llvm/llvm-wrapper/PassWrapper.cpp#L393 The LLVM name for this, `X86RelaxRelocations`, makes me believe that this is x86-only. So let's at least document that on our side as well. Cc @bjorn3 @nikic

Remove needs-triage label from relnotes issues Context: [#t-release > &rust-lang#96;relnotes-needs-review&rust-lang#96; tag?](https://rust-lang.zulipchat.com/#narrow/channel/241545-t-release/topic/.60relnotes-needs-review.60.20tag.3F/with/627107555) r? jieyouxu

JonathanBrouwer · 2026-10-08T06:56:14Z

@bors r+ p=5 force

Trying commonly failed jobs
@bors try jobs=dist-various-1,test-various,test-x86_64-gnu-aux,test-x86_64-msvc-1,test-aarch64-apple-1,test-aarch64-apple-2,test-x86_64-mingw-1,test-i686-msvc,test-armhf-gnu,test-x86_64-gnu-llvm-22-3

rust-bors · 2026-10-08T06:56:17Z

📌 Commit 61789a5 has been approved by JonathanBrouwer

It is now in the queue for this repository.

Rollup of 11 pull requests try-job: dist-various-1 try-job: test-various try-job: test-x86_64-gnu-aux try-job: test-x86_64-msvc-1 try-job: test-aarch64-apple-1 try-job: test-aarch64-apple-2 try-job: test-x86_64-mingw-1 try-job: test-i686-msvc try-job: test-armhf-gnu try-job: test-x86_64-gnu-llvm-22-3

rust-log-analyzer · 2026-10-08T07:48:24Z

The job test-i686-msvc failed! Check out the build log: (web) (plain enhanced) (plain)

Click to see the possible cause of the failure (guessed by this bot)

compile::Assemble { target_compiler: Compiler { stage: 2, host: x86_64-pc-windows-msvc, forced_compiler: false } } at src\bootstrap\src\core\build_steps\test.rs:2025
compile::Assemble { target_compiler: Compiler { stage: 1, host: x86_64-pc-windows-msvc, forced_compiler: false } } at src\bootstrap\src\core\build_steps\compile.rs:2290
compile::CraneliftCodegenBackend { compilers: RustcPrivateCompilers { build_compiler: Compiler { stage: 0, host: x86_64-pc-windows-msvc, forced_compiler: false }, target_compiler: Compiler { stage: 1, host: x86_64-pc-windows-msvc, forced_compiler: false } } } at src\bootstrap\src\core\build_steps\compile.rs:2422
Build completed unsuccessfully in 0:33:16
make: *** [Makefile:115: ci-msvc-py] Error 1
  local time: Thu Oct  8 07:37:40 CUT 2026
  network time: Thu, 08 Oct 2026 07:37:41 GMT
##[error]Process completed with exit code 2.
##[group]Run echo "disk usage:"
echo "disk usage:"

rust-bors · 2026-10-08T09:53:14Z

💔 Test for 4ca31b8 failed: CI. Failed job:

try - test-i686-msvc (web logs, enhanced plaintext logs)

rust-log-analyzer · 2026-10-08T09:53:18Z

The job test-i686-msvc failed! Check out the build log: (web) (plain enhanced) (plain)

Click to see the possible cause of the failure (guessed by this bot)

compile::Assemble { target_compiler: Compiler { stage: 2, host: x86_64-pc-windows-msvc, forced_compiler: false } } at src\bootstrap\src\core\build_steps\test.rs:2025
compile::Assemble { target_compiler: Compiler { stage: 1, host: x86_64-pc-windows-msvc, forced_compiler: false } } at src\bootstrap\src\core\build_steps\compile.rs:2290
compile::CraneliftCodegenBackend { compilers: RustcPrivateCompilers { build_compiler: Compiler { stage: 0, host: x86_64-pc-windows-msvc, forced_compiler: false }, target_compiler: Compiler { stage: 1, host: x86_64-pc-windows-msvc, forced_compiler: false } } } at src\bootstrap\src\core\build_steps\compile.rs:2422
Build completed unsuccessfully in 0:33:16
make: *** [Makefile:115: ci-msvc-py] Error 1
  local time: Thu Oct  8 07:37:40 CUT 2026
  network time: Thu, 08 Oct 2026 07:37:41 GMT
##[error]Process completed with exit code 2.
##[group]Run echo "disk usage:"
echo "disk usage:"

rust-bors · 2026-10-08T10:24:30Z

☀️ Test successful - CI
Approved by: JonathanBrouwer
Duration: 2h 58m 18s
Pushing fc2324d to main...

github-actions · 2026-10-08T10:27:45Z

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 42cfc04 (parent) -> fc2324d (this PR)

Test differences

Show 85 test diffs

Stage 1

[codegen] tests/codegen-llvm/enum/enum-discriminant-power-of-two.rs: [missing] -> pass (J2)
[ui] tests/ui/async-await/witness-auto-trait/higher-ranked-auto-trait-1.rs#assumptions_next: [missing] -> pass (J3)
[rustdoc-html] tests/rustdoc-html/jump-to-def/link-to-alloc.rs: [missing] -> pass (J5)
[ui (polonius)] tests/ui/async-await/witness-auto-trait/higher-ranked-auto-trait-1.rs#assumptions_next: [missing] -> pass (J6)

Stage 2

[rustdoc-html] tests/rustdoc-html/jump-to-def/link-to-alloc.rs: [missing] -> pass (J0)
[codegen] tests/codegen-llvm/enum/enum-discriminant-power-of-two.rs: [missing] -> pass (J1)
[ui] tests/ui/async-await/witness-auto-trait/higher-ranked-auto-trait-1.rs#assumptions_next: [missing] -> pass (J4)

Additionally, 78 doctest diffs were found. These are ignored, as they are noisy.

Job group index

Test dashboard

Run

cargo run --manifest-path src/ci/citool/Cargo.toml -- \
    test-dashboard fc2324d0546aa6782c45b76247266a0c37db0b8a --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

test-x86_64-gnu-stdlib-semver-check: 7m 58s -> 15m 20s (+92.5%)
test-x86_64-rust-for-linux: 33m 25s -> 1h 1m (+82.7%)
test-i686-gnu-nopt-1: 1h 21m -> 2h 22m (+75.3%)
test-x86_64-msvc-ext3: 1h 9m -> 1h 56m (+66.6%)
dist-arm-linux-musl: 1h 6m -> 1h 51m (+66.0%)
test-x86_64-gnu-stable: 1h 36m -> 2h 38m (+64.1%)
dist-riscv64-linux-musl: 58m 5s -> 1h 33m (+60.8%)
optional-test-x86_64-gnu-autodiff: 37m 39s -> 58m 17s (+54.8%)
test-pr-check-1: 25m 12s -> 39m (+54.8%)
dist-x86_64-solaris: 1h 11m -> 1h 48m (+51.0%)

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 · 2026-10-08T11:13:49Z

Finished benchmarking commit (fc2324d): 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%, 0.1%]	5
Improvements ✅ (primary)	-	-	0
Improvements ✅ (secondary)	-	-	0
All ❌✅ (primary)	-	-	0

Max RSS (memory usage)

Results (primary 0.3%, secondary -2.0%)

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

	mean	range	count
Regressions ❌ (primary)	1.3%	[1.2%, 1.4%]	2
Regressions ❌ (secondary)	-	-	0
Improvements ✅ (primary)	-0.7%	[-0.8%, -0.6%]	2
Improvements ✅ (secondary)	-2.0%	[-2.6%, -1.3%]	3
All ❌✅ (primary)	0.3%	[-0.8%, 1.4%]	4

Cycles

Results (secondary 2.7%)

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)	8.5%	[6.5%, 10.5%]	2
Improvements ✅ (primary)	-	-	0
Improvements ✅ (secondary)	-3.1%	[-4.2%, -2.0%]	2
All ❌✅ (primary)	-	-	0

Binary size

Results (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
Improvements ✅ (secondary)	-0.1%	[-0.1%, -0.1%]	1
All ❌✅ (primary)	-	-	0

Bootstrap: 489.959s -> 484.956s (-1.02%)
Artifact size: 408.60 MiB -> 406.45 MiB (-0.53%)

rust-bors · 2026-10-08T11:30:40Z

📌 Perf builds for each rolled up PR:

PR#	Message	Perf Build Sha
#162741	codegen: tell LLVM that the discriminant is a power of two	`a341e0ee37271a55935153891f2ac232210f70a5` (link)
#162758	Split PassMode::IndirectUnsized out of PassMode::Indirect	`780d9a7aa7ea14ed924768ce9d9e048b87b06498` (link)
#163931	Move `loop_hint_attrs` from `Terminator` into `TerminatorKi…	`34bacc1820a9d57d9a47555594f8290513e504dc` (link)
#163028	autodiff: fix sysroot candidates in libEnzyme not found err…	`72e3e2dab6ea803f96612c5ea841fc8dad702e04` (link)
#163257	abby DSL: sanity checks on forall where clauses	`4a241c2964ff6bfe4930c6780017fe44894e08fc` (link)
#163841	[rustdoc] Fix more `incoherent_impl` linking	`079459306ebc064542bf6d8440bd7bd23ce8f295` (link)
#163908	Update Enzyme submodule	`49a365027c7e7620d91ab383bac593366a650feb` (link)
#163935	Use BasicBlock::start_location and Location::START	`64635941417d7b84a8055e8706e89ec9b1520f26` (link)
#163949	disable next-solver with higher-ranked-assumptions	`6b1a8f8e95003a13c9b8a5690d02e543f95084ab` (link)
#163951	relax_elf_relocations is x86-only	`0b098eb0b0a5c1783be03e2a66bd9c295583a005` (link)
#163968	Remove needs-triage label from relnotes issues	`1005da9e91c0b0a708b72728291b67a31dca06f5` (link)

parent commit: 42cfc04dea

In the case of a perf regression, run the following command with the SHAs of each PR you suspect might be the cause: @rust-timer triage $SHA $SHA $SHA..., or run @rust-timer triage all to benchmark all rollup members.

sgasho and others added 24 commits September 19, 2026 16:43

autodiff: fix sysroot candidates in libEnzyme not found error

38d5ee3

Fix more incoherent_impl linking

4ba952a

Update Enzyme submodule

9a6d547

Store loop hints as UnrollAttr rather than AttributeKind

48156cc

This will make it easier to move them in a subsequent commit, since `UnrollAttr` implements `PartialEq`. If, in the future, we add more kinds of loop hints, this can become a small enum wrapping only those attr types.

Use BasicBlock::start_location and Location::START

6545abe

Update Enzyme submodule again

0d7fdb5

relax_elf_relocations is x86-only

6396944

disable next-solver with higher-ranked-assumptions

7870b60

Remove needs-triage label from relnotes PRs

47b4d94

abby: ensure forall where clause lhs is alias, placeholder, or lifetime

caa9037

Rollup merge of rust-lang#163908 - ZuseZ4:update-enzyme-oct-06-2026, …

febebe3

…r=ZuseZ4 Update Enzyme submodule r? ZuseZ4 cc @wsmoses @bors try jobs=dist-x86_64-linux,optional-test-x86_64-gnu-autodiff

Rollup merge of rust-lang#163935 - tmiasko:start-location, r=beetrees

6b354e2

Use BasicBlock::start_location and Location::START Construct special MIR locations concisely.

Rollup merge of rust-lang#163949 - lcnr:higher-ranked-assumptions-yee…

a0e7eb5

…t, r=lqd disable next-solver with higher-ranked-assumptions that's nicer than needing to update all the `[assumptions]` ui tests I think r? @lqd or @BoxyUwU

rust-bors Bot added the rollup A PR which is a rollup label Oct 8, 2026

rustbot added the T-rustdoc-frontend Relevant to the rustdoc-frontend team, which will review and decide on the web UI/UX output. label Oct 8, 2026

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 Oct 8, 2026

This comment has been minimized.

Sign in to view

rust-bors Bot added the S-waiting-on-author Status: This is awaiting some action (such as code changes or more information) from the author. label Oct 8, 2026

rust-bors Bot added the merged-by-bors This PR was explicitly merged by bors. label Oct 8, 2026

rust-bors Bot removed the S-waiting-on-bors Status: Waiting on bors to run and complete tests. Bors will change the label on completion. label Oct 8, 2026

rust-bors Bot merged commit fc2324d into rust-lang:main Oct 8, 2026
15 of 16 checks passed

rustbot removed the S-waiting-on-author Status: This is awaiting some action (such as code changes or more information) from the author. label Oct 8, 2026

rustbot added this to the 1.101.0 milestone Oct 8, 2026

Navigation Menu

Repository navigation

Rollup of 11 pull requests - #163970

Rollup of 11 pull requests#163970
rust-bors[bot] merged 24 commits into
rust-lang:mainfrom
JonathanBrouwer:rollup-ntScez1

JonathanBrouwer commented Oct 8, 2026

Uh oh!

JonathanBrouwer commented Oct 8, 2026

Uh oh!

rust-bors Bot commented Oct 8, 2026

Uh oh!

This comment has been minimized.

This comment has been minimized.

rust-log-analyzer commented Oct 8, 2026

Uh oh!

rust-bors Bot commented Oct 8, 2026

Uh oh!

rust-log-analyzer commented Oct 8, 2026

Uh oh!

rust-bors Bot commented Oct 8, 2026

Uh oh!

Uh oh!

github-actions Bot commented Oct 8, 2026

Stage 1

Stage 2

Uh oh!

rust-timer commented Oct 8, 2026

Uh oh!

rust-bors Bot commented Oct 8, 2026

Uh oh!

Reviewers

Assignees

Labels

Projects

Milestone

Development

Uh oh!

15 participants

Conversation

JonathanBrouwer commented Oct 8, 2026

Uh oh!

JonathanBrouwer commented Oct 8, 2026

Uh oh!

rust-bors Bot commented Oct 8, 2026

Uh oh!

This comment has been minimized.

This comment has been minimized.

rust-log-analyzer commented Oct 8, 2026

Uh oh!

rust-bors Bot commented Oct 8, 2026

Uh oh!

rust-log-analyzer commented Oct 8, 2026

Uh oh!

rust-bors Bot commented Oct 8, 2026

Uh oh!

Uh oh!

github-actions Bot commented Oct 8, 2026

Test differences

Stage 1

Stage 2

Job duration changes

Uh oh!

rust-timer commented Oct 8, 2026

Overall result: ❌ regressions - no action needed

Instruction count

Max RSS (memory usage)

Cycles

Binary size

Uh oh!

rust-bors Bot commented Oct 8, 2026

Uh oh!

Reviewers

Assignees

Labels

Projects

Milestone

Development

Uh oh!

15 participants