rust/tests/codegen, branch try

Rollup merge of #144080 - jieyouxu:realign, r=BoxyUwU

2025-07-21T16:54:28+00:00

Mitigate `#[align]` name resolution ambiguity regression with a rename Mitigates beta regression rust-lang/rust#143834 after a beta backport. ### Background on the beta regression The name resolution regression arises due to rust-lang/rust#142507 adding a new feature-gated built-in attribute named `#[align]`. However, unfortunately even [introducing new feature-gated unstable built-in attributes can break user code](https://www.github.com/rust-lang/rust/issues/134963) such as ```rs macro_rules! align { () => { /* .. */ }; } pub(crate) use align; // `use` here becomes ambiguous ``` ### Mitigation approach This PR renames `#[align]` to `#[rustc_align]` to mitigate the beta regression by: 1. Undoing the introduction of a new built-in attribute with a common name, i.e. `#[align]`. 2. Renaming `#[align]` to `#[rustc_align]`. The renamed attribute being `rustc_align` will not introduce new stable breakages, as attributes beginning with `rustc` are reserved and perma-unstable. This does mean existing nightly code using `fn_align` feature will additionally need to specify `#![feature(rustc_attrs)]`. This PR is very much a short-term mitigation to alleviate time pressure from having to fully fix the current limitation of inevitable name resolution regressions that would arise from adding any built-in attributes. Long-term solutions are discussed in [#t-lang > namespacing macro attrs to reduce conflicts with new adds](https://rust-lang.zulipchat.com/#narrow/channel/213817-t-lang/topic/namespacing.20macro.20attrs.20to.20reduce.20conflicts.20with.20new.20adds/with/529249622). ### Alternative mitigation options [Various mitigation options were considered during the compiler triage meeting](https://github.com/rust-lang/rust/issues/143834#issuecomment-3084415277), and those consideration are partly reproduced here: - Reverting the PR doesn't seem very minimal/trivial, and carries risks of its own. - Rename to a less-common but aim-to-stabilization name is itself not safe nor convenient, because (1) that risks introducing new regressions (i.e. ambiguity against the new name), and (2) lang would have to FCP the new name hastily for the mitigation to land timely and have a chance to be backported. This also makes the path towards stabilization annoying. - Rename the attribute to a rustc attribute, which will be perma-unstable and does not cause new ambiguities in stable code. - This alleviates the time pressure to address *this* regression, or for lang to have to rush an FCP for some new name that can still break user code. - This avoids backing out a whole implementation. ### Review advice This PR is best reviewed commit-by-commit. - Commit 1 adds a test `tests/ui/attributes/fn-align-nameres-ambiguity-143834.rs` which demonstrates the current name resolution regression re. `align`. This test fails against current master. - Commit 2 carries out the renames and test reblesses. Notably, commit 2 will cause `tests/ui/attributes/fn-align-nameres-ambiguity-143834.rs` to change from fail (nameres regression) to pass. This PR, if the approach still seems acceptable, will need a beta-backport to address the beta regression.

Rollup merge of #142097 - ZuseZ4:offload-host1, r=oli-obk

2025-07-21T16:54:24+00:00

gpu offload host code generation r? ghost This will generate most of the host side code to use llvm's offload feature. The first PR will only handle automatic mem-transfers to and from the device. So if a user calls a kernel, we will copy inputs back and forth, but we won't do the actual kernel launch. Before merging, we will use LLVM's Info infrastructure to verify that the memcopies match what openmp offloa generates in C++. `LIBOMPTARGET_INFO=-1 ./my_rust_binary` should print that a memcpy to and later from the device is happening. A follow-up PR will generate the actual device-side kernel which will then do computations on the GPU. A third PR will implement manual host2device and device2host functionality, but the goal is to minimize cases where a user has to overwrite our default handling due to performance issues. I'm trying to get a full MVP out first, so this just recognizes GPU functions based on magic names. The final frontend will obviously move this over to use proper macros, like I'm already doing it for the autodiff work. This work will also be compatible with std::autodiff, so one can differentiate GPU kernels. Tracking: - https://github.com/rust-lang/rust/issues/131513

Ban projecting into SIMD types [MCP838]

2025-07-20T17:22:09+00:00

So many test updates x_x

2025-07-20T17:15:14+00:00

Split repeat-operand codegen test

2025-07-20T03:50:02+00:00

Looks like the output it's looking for can be in different orders, so separate tests will fix that.

Allow `Rvalue::Repeat` to return true in `rvalue_creates_operand` too

2025-07-20T03:50:02+00:00

The conversation in 143502 made be realize how easy this is to handle, since the only possibilty is ZSTs -- everything else ends up with the destination being `LocalKind::Memory` and thus doesn't call `codegen_rvalue_operand` at all. This gets us perilously close to a world where `rvalue_creates_operand` only ever returns true. I'll try out such a world next :)

Auto merge of #143784 - scottmcm:enums-again-new-ex2, r=dianqk

2025-07-19T08:03:40+00:00

Simplify discriminant codegen for niche-encoded variants which don't wrap across an integer boundary Inspired by rust-lang/rust#139729, this attempts to be a much-simpler and more-localized change while still making a difference. (Specifically, this does not try to solve the problem with select-sinking, leaving that to be fixed by https://github.com/llvm/llvm-project/issues/134024 -- once it gets released -- instead of in rustc's codegen.) What this *does* improve is checking for the variant in a 3+ variant enum when that variant is the type providing the niche. Something like `if let Foo::WithBool(_) = ...` previously compiled to `ugt(add(x, -2), 2)`, which is non-trivial to think about because it's depending on the unsigned wrapping to shift the 0/1 up above 2. With this PR it compiles to just `ult(x, 2)`, which is probably what you'd have written yourself if you were doing it by hand to look for "is this byte a bool?". That's done by leaving most of the codegen alone, but adding a couple new special cases to the `is_niche` check. The default looks at the relative discriminant, but in the common cases where there's no wraparound involved, we can just check the original value, rather than the offsetted one. The first commit just adds some tests, so the best way to see the effect of this change is to look at the second commit and how it updates the test expectations.

add gpu offload codegen host side test

2025-07-18T23:30:46+00:00

Mitigate `#[align]` name resolution ambiguity regression with a rename

2025-07-18T17:42:30+00:00

From `#[align]` -> `#[rustc_align]`. Attributes starting with `rustc` are always perma-unstable and feature-gated by `feature(rustc_attrs)`. See regression RUST-143834. For the underlying problem where even introducing new feature-gated unstable built-in attributes can break user code such as ```rs macro_rules! align { () => { /* .. */ }; } pub(crate) use align; // `use` here becomes ambiguous ``` refer to RUST-134963. Since the `#[align]` attribute is still feature-gated by `feature(fn_align)`, we can rename it as a mitigation. Note that `#[rustc_align]` will obviously mean that current unstable user code using `feature(fn_aling)` will need additionally `feature(rustc_attrs)`, but this is a short-term mitigation to buy time, and is expected to be changed to a better name with less collision potential. See where mitigation options were considered.

Rollup merge of #143293 - folkertdev:naked-function-kcfi, r=compiler-errors

2025-07-18T02:27:51+00:00

fix `-Zsanitizer=kcfi` on `#[naked]` functions fixes https://github.com/rust-lang/rust/issues/143266 With `-Zsanitizer=kcfi`, indirect calls happen via generated intermediate shim that forwards the call. The generated shim preserves the attributes of the original, including `#[unsafe(naked)]`. The shim is not a naked function though, and violates its invariants (like having a body that consists of a single `naked_asm!` call). My fix here is to match on the `InstanceKind`, and only use `codegen_naked_asm` when the instance is not a `ReifyShim`. That does beg the question whether there are other `InstanceKind`s that could come up. As far as I can tell the answer is no: calling via `dyn` seems to work find, and `#[track_caller]` is disallowed in combination with `#[naked]`. r? codegen ````@rustbot```` label +A-naked cc ````@maurer```` ````@rcvalle````