Rollup of 7 pull requests#154773
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rust-bors[bot] merged 26 commits intorust-lang:mainfrom Apr 4, 2026
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As requested by @lcnr
Instead of just using regular struct lowering for these types, which results in an incorrect ABI (e.g. returning indirectly), use `BackendRepr::ScalableVector` which will lower to the correct type and be passed in registers. This also enables some simplifications for generating alloca of scalable vectors and greater re-use of `scalable_vector_parts`. A LLVM codegen test demonstrating the changed IR this generates is included in the next commit alongside some intrinsics that make these tuples usable.
Clang changed to representing tuples of scalable vectors as
structs rather than as wide vectors (that is, scalable vector types
where the `N` part of the `<vscale x N x ty>` type was multiplied by
the number of vectors). rustc mirrored this in the initial implementation
of scalable vectors.
Earlier versions of our patches used the wide vector representation and
our intrinsic patches used the legacy
`llvm.aarch64.sve.tuple.{create,get,set}{2,3,4}` intrinsics for creating
these tuples/getting/setting the vectors, which were only supported
due to LLVM's `AutoUpgrade` pass converting these intrinsics into
`llvm.vector.insert`. `AutoUpgrade` only supports these legacy intrinsics
with the wide vector representation.
With the current struct representation, Clang has special handling in
codegen for generating `insertvalue`/`extractvalue` instructions for
these operations, which must be replicated by rustc's codegen for our
intrinsics to use. This patch implements new intrinsics in
`core::intrinsics::scalable` (mirroring the structure of
`core::intrinsics::simd`) which rustc lowers to the appropriate
`insertvalue`/`extractvalue` instructions.
Generate debuginfo for scalable vectors, following the structure that Clang generates for scalable vectors.
Abstract over the existing `simd_cast` intrinsic to implement a new `sve_cast` intrinsic - this is better than allowing scalable vectors to be used with all of the generic `simd_*` intrinsics.
various fixes for scalable vectors
These are a handful of patches fixing bugs with the current `#[rustc_scalable_vector]` infrastructure so that we can upstream the intrinsics to stdarch:
1. Instead of just using regular struct lowering for tuples of scalable vectors, which results in an incorrect ABI (e.g. returning indirectly), we change to using `BackendRepr::ScalableVector` which will lower to the correct type and be passed in registers.
2. Clang changed from representing tuples of scalable vectors as structs rather than as wide vectors (that is, scalable vector types where the `N` part of the `<vscale x N x ty>` type was multiplied by the number of vectors). rustc mirrored this in the initial implementation of scalable vectors that didn't land.
When our early patches used the wide vector representation, our intrinsic patches used the legacy `llvm.aarch64.sve.tuple.{create,get,set}{2,3,4}` intrinsics for creating these tuples/getting/setting the vectors, which were only supported due to LLVM's `AutoUpgrade` pass converting these intrinsics into `llvm.vector.insert`. `AutoUpgrade` only supports these legacy intrinsics with the wide vector representation.
With the current struct representation, Clang has special handling in codegen for generating `insertvalue`/`extractvalue` instructions for these operations, which must be replicated by rustc's codegen for our intrinsics to use.
We add a new `core::intrinsics::scalable` module (never intended to be stable, just used by the stdarch intrinsics, gated by `core_intrinsics`) and add new intrinsics which rustc lowers to the appropriate `insertvalue`/`extractvalue` instructions.
3. Add generation of debuginfo for scalable vectors, following the DWARF that Clang generates.
4. Some intrinsics need something like `simd_cast`, which will work for scalable vectors too, so this implements a new `sve_cast` intrinsic that uses the same internals as `simd_cast`. This seemed better than permitting scalable vectors to be used with the `simd_*` intrinsics more generally as I can't guarantee this would work for all of them.
This is a relatively large patch but most of it is tests, and each commit should be relatively standalone. It's a little bit easier to upstream them together to avoid needing to stack them. It's possible that some more compiler fixes will be forthcoming but it's looking like this might be all at the moment.
Depends on rust-lang#153653
r? @workingjubilee (discussed on Zulip)
…d_privacy-gate, r=BoxyUwU Add `min_adt_const_params` gate Add `min_adt_const_params` feature gate to disallow `ConstParamTy_` impl for types which fields visibility mismatches with struct itself r? BoxyUwU
…te-field-deref-fresh, r=estebank Improve shadowed private field diagnostics Fixes rust-lang#149546 I tried to extend the diagnostic to more scenarios, like method call, type mismatch errors. r? @estebank
…Brouwer Remove rustc_on_unimplemented's append_const_msg This does nothing because it is unreachable within the compiler. It also doesn't seem that useful since all the traits it was on are `const` now. Will make pr to rustc-dev-guide docs later.
…le-impls, r=TaKO8Ki Remove an unused `StableHash` impl. r? @TaKO8Ki
…278, r=jackh726 Add tests for three ICEs that have already been fixed Closes rust-lang#113870. Closes rust-lang#114056. Closes rust-lang#118278.
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Auto build was cancelled. Cancelled workflows: The next pull request likely to be tested is #154773. |
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Rollup of 7 pull requests Successful merges: - #153286 (various fixes for scalable vectors) - #153592 (Add `min_adt_const_params` gate) - #154675 (Improve shadowed private field diagnostics) - #154653 (Remove rustc_on_unimplemented's append_const_msg) - #154743 (Remove an unused `StableHash` impl.) - #154752 (Add comment to borrow-checker) - #154764 (Add tests for three ICEs that have already been fixed)
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💔 Test for 4e174c4 failed: CI. Failed job:
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📌 Perf builds for each rolled up PR:
previous master: 2972b5e59f In the case of a perf regression, run the following command for each PR you suspect might be the cause: |
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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 2972b5e (parent) -> 981cf69 (this PR) Test differencesShow 390 test diffsStage 1
Stage 2
Additionally, 339 doctest diffs were found. These are ignored, as they are noisy. Job group index
Test dashboardRun cargo run --manifest-path src/ci/citool/Cargo.toml -- \
test-dashboard 981cf69479ded5e2de0cf9e16111c19d65be0369 --output-dir test-dashboardAnd then open Job duration changes
How to interpret the job duration changes?Job durations can vary a lot, based on the actual runner instance |
This was referenced Apr 4, 2026
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Finished benchmarking commit (981cf69): comparison URL. Overall result: ❌✅ regressions and improvements - no action needed@rustbot label: -perf-regression Instruction countOur most reliable metric. Used to determine the overall result above. However, even this metric can be noisy.
Max RSS (memory usage)Results (primary -0.0%, secondary -1.8%)A less reliable metric. May be of interest, but not used to determine the overall result above.
CyclesResults (secondary 4.4%)A less reliable metric. May be of interest, but not used to determine the overall result above.
Binary sizeResults (primary 0.0%, secondary 0.0%)A less reliable metric. May be of interest, but not used to determine the overall result above.
Bootstrap: 489.759s -> 485.459s (-0.88%) |
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Successful merges:
min_adt_const_paramsgate #153592 (Addmin_adt_const_paramsgate)StableHashimpl. #154743 (Remove an unusedStableHashimpl.)r? @ghost
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