GCC backend subtree sync by GuillaumeGomez · Pull Request #155978 · rust-lang/rust

GuillaumeGomez · 2026-04-29T21:26:38Z

r? ghost

@Manishearth

…nishearth Clippy subtree update r? @Manishearth 1 week late, due to vacation and some technical issues.

…update_cg_gcc_2026-02-14

It was just a dummy implementation to workarround the fact that thin local lto is the default in rustc. By adding a thin_lto_supported thin local lto can be automatically disabled for cg_gcc, removing the need for this dummy implementation. This makes improvements to the LTO handling on the cg_ssa side a lot easier.

Simplify running tests

This allows us to get rid of box_new entirely

Fix CI

…mpile

…ded in this case

Split `compile` tests from `run` tests

This allows removing the Metadata associated type from BackendTypes.

In Cranelift the regular Type enum can't represent function signatures. Function pointers are represented as plain pointer sized integer.

Previously this was not correctly implemented. Each funclet may need its own terminate block, so this changes the `terminate_block` into a `terminate_blocks` `IndexVec` which can have a terminate_block for each funclet. We key on the first basic block of the funclet -- in particular, this is the start block for the old case of the top level terminate function. Rather than using a catchswitch/catchpad pair, I used a cleanuppad. The reason for the pair is to avoid catching foreign exceptions on MSVC. On wasm, it seems that the catchswitch/catchpad pair is optimized back into a single cleanuppad and a catch_all instruction is emitted which will catch foreign exceptions. Because the new logic is only used on wasm, it seemed better to take the simpler approach seeing as they do the same thing.

In Cranelift a Value can't hold arbitrarily sized values.

Add regression test for rust-lang#298

Update GCC version

rustbot · 2026-04-29T21:31:01Z

⚠️ 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.
There are issue links (such as #123) in the commit messages of the following commits.
Please move them to the PR description, to avoid spamming the issues with references to the commit, and so this bot can automatically canonicalize them to avoid issues with subtree.
- 552fc2f
- daf8bb9
The following commits have merge commits (commits with multiple parents) in your changes. We have a no merge policy so these commits will need to be removed for this pull request to be merged.
- 0be3954
- 1b01acd
- 1c333b6
- 2205317
- 2640671
- 2980d50
- 39e47ae
- 3c3d98f
- 445413c
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- c936fd9
- ceafbd1
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You can start a rebase with the following commands:
```
$ # rebase
$ git pull --rebase https://github.com/rust-lang/rust.git main
$ git push --force-with-lease
```

antoyo

Thanks!

View changes since this review

GuillaumeGomez · 2026-04-29T23:23:38Z

@bors r=antoyo rollup=never p=1

rust-bors · 2026-04-29T23:23:41Z

📌 Commit f3d34dc has been approved by antoyo

It is now in the queue for this repository.

rust-bors · 2026-04-30T07:29:45Z

☀️ Test successful - CI
Approved by: antoyo
Duration: 3h 15m 39s
Pushing 57f772f to main...

github-actions · 2026-04-30T07:32:56Z

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 a021a77 (parent) -> 57f772f (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 57f772f25c5ce2bd870d6f8c3ab318eaee5a3326 --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-aarch64-linux: 1h 43m -> 2h 30m (+45.0%)
x86_64-gnu-llvm-21: 1h 13m -> 1h 39m (+35.1%)
x86_64-gnu-gcc: 1h 6m -> 1h 24m (+28.4%)
x86_64-rust-for-linux: 53m 50s -> 39m 2s (-27.5%)
i686-msvc-1: 3h 7m -> 2h 16m (-27.3%)
i686-gnu-nopt-1: 2h 22m -> 1h 49m (-23.4%)
dist-i686-msvc: 2h 21m -> 1h 48m (-23.2%)
dist-x86_64-apple: 2h 21m -> 1h 50m (-22.1%)
dist-x86_64-msvc-alt: 2h 10m -> 2h 39m (+21.9%)
x86_64-gnu-debug: 2h 1m -> 1h 36m (-20.5%)

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 · 2026-04-30T09:47:17Z

Finished benchmarking commit (57f772f): comparison URL.

Overall result: no relevant changes - no action needed

@rustbot label: -perf-regression

Instruction count

This perf run didn't have relevant results for this metric.

Max RSS (memory usage)

This perf run didn't have relevant results for this metric.

Cycles

This perf run didn't have relevant results for this metric.

Binary size

This perf run didn't have relevant results for this metric.

Bootstrap: 480.95s -> 483.007s (0.43%)
Artifact size: 390.98 MiB -> 391.00 MiB (0.00%)

…29, r=antoyo GCC backend subtree sync r? ghost

…jorn3 Reflect current PR title names for subtree syncs in triagebot no-merges Noticed that the current PR title names for subtree syncs seems to have changed (or at least for some) and is now "Subtree sync" (or it's lower-cased variant). Let's update the triagebot config so the merge commit handler don't for those expected cases. - rust-lang#157533 (comment) - rust-lang#155978 (comment)

Rollup merge of #161367 - Urgau:triagebot-no-merges-upd, r=bjorn3 Reflect current PR title names for subtree syncs in triagebot no-merges Noticed that the current PR title names for subtree syncs seems to have changed (or at least for some) and is now "Subtree sync" (or it's lower-cased variant). Let's update the triagebot config so the merge commit handler don't for those expected cases. - #157533 (comment) - #155978 (comment)

Reflect current PR title names for subtree syncs in triagebot no-merges Noticed that the current PR title names for subtree syncs seems to have changed (or at least for some) and is now "Subtree sync" (or it's lower-cased variant). Let's update the triagebot config so the merge commit handler don't for those expected cases. - rust-lang/rust#157533 (comment) - rust-lang/rust#155978 (comment)

GuillaumeGomez and others added 30 commits February 12, 2026 14:57

Simplify running tests

86fbc24

cg_gcc: remove Clippy expect attribute

520806e

Auto merge of rust-lang#152533 - flip1995:clippy-subtree-update, r=Ma…

3c3d98f

…nishearth Clippy subtree update r? @Manishearth 1 week late, due to vacation and some technical issues.

Merge commit '70ae207ff5dcd67931c0e67cb62ebceec75a7436' into subtree-…

d8d041d

…update_cg_gcc_2026-02-14

Fix libgccjit version

e96a4e2

Correctly split between release and debug lang tests run

813ddbf

Merge pull request rust-lang#845 from GuillaumeGomez/simplify-tests

0be3954

Simplify running tests

add write_box_via_move intrinsic and use it for vec!

d02e45a

This allows us to get rid of box_new entirely

Remove ModuleBuffer ThinBuffer duplication

dc3e9cc

Simplify function signatures of serialize_module and prepare_thin

b1ab6bc

Remove last remaining ModuleBuffer/ThinBuffer duplication

0aa7ba6

Fix CI

0ca7071

Merge pull request rust-lang#855 from rust-lang/fix/ci

2640671

Fix CI

Allow to have compile-only tests

ea89e82

Move intrinsics tests into tests/compile since they only need to co…

615476a

…mpile

Move more code between the run_binary condition since it's only nee…

ec14a11

…ded in this case

Ignore compile/simd-ffi.rs test on m68k target

01cda7d

Improve code readability of tests/lang_tests.rs

2bb1a43

Merge pull request rust-lang#846 from GuillaumeGomez/compile-only

dc273bf

Split `compile` tests from `run` tests

Merge typeid_metadata into type_checked_load

383bd74

This allows removing the Metadata associated type from BackendTypes.

Reorder associated types in BackendTypes to be a bit more logical

755b5b0

allow clippy::collapsible_match in cg_gcc

9604a5f

Add regression test for <rust-lang/rustc_codegen_gcc#298>

2818318

Introduce FunctionSignature associated type for BackendTypes

977712b

In Cranelift the regular Type enum can't represent function signatures. Function pointers are represented as plain pointer sized integer.

Merge const_data_from_alloc into static_addr_of

1827789

In Cranelift a Value can't hold arbitrarily sized values.

Merge pull request rust-lang#847 from GuillaumeGomez/log-test

bc4a848

Add regression test for rust-lang#298

Update GCC version

f99b85c

Merge pull request rust-lang#856 from rust-lang/update-gcc

66d6f7b

Update GCC version

rustbot added has-merge-commits PR has merge commits, merge with caution. S-waiting-on-author Status: This is awaiting some action (such as code changes or more information) from the author. labels Apr 29, 2026

Update GCC submodule

04c5d1e

antoyo approved these changes Apr 29, 2026

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Fix tidy errors in cg_gcc

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rust-bors Bot added merged-by-bors This PR was explicitly merged by bors. and removed S-waiting-on-bors Status: Waiting on bors to run and complete tests. Bors will change the label on completion. labels Apr 30, 2026

rust-bors Bot merged commit 57f772f into rust-lang:main Apr 30, 2026
12 checks passed

rustbot added this to the 1.97.0 milestone Apr 30, 2026

rust-bors Bot mentioned this pull request Apr 30, 2026

Support using const pointers in asm const operand #138618

Merged

antoyo mentioned this pull request Apr 30, 2026

Mangle personality symbol #148413

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GuillaumeGomez deleted the subtree-update_cg_gcc_2026-04-29 branch April 30, 2026 13:30

rust-bors Bot pushed a commit that referenced this pull request Jul 24, 2026

Auto merge of #155978 - GuillaumeGomez:subtree-update_cg_gcc_2026-04-…

efbbd33

…29, r=antoyo GCC backend subtree sync r? ghost

Urgau mentioned this pull request Aug 19, 2026

Reflect current PR title names for subtree syncs in triagebot no-merges #161367

Merged

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GCC backend subtree sync - #155978

GCC backend subtree sync#155978
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Overall result: no relevant changes - no action needed

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