Rollup of 6 pull requests
Successful merges:
- #137674 (Enable `f16` for LoongArch)
- #138034 (library: Use `size_of` from the prelude instead of imported)
- #138060 (Revert #138019 after further discussion about how hir-pretty printing should work)
- #138073 (Break critical edges in inline asm before code generation)
- #138107 (`librustdoc`: clippy fixes)
- #138111 (Use `default_field_values` for `rustc_errors::Context`, `rustc_session::config::NextSolverConfig` and `rustc_session::config::ErrorOutputType`)
r? `@ghost`
`@rustbot` modify labels: rollup
library: Use `size_of` from the prelude instead of imported
Use `std::mem::{size_of, size_of_val, align_of, align_of_val}` from the prelude instead of importing or qualifying them.
These functions were added to all preludes in Rust 1.80.
try-job: test-various
try-job: x86_64-gnu
try-job: x86_64-msvc-1
Stabilize const_char_classify, const_sockaddr_setters
FCP for const_char_classify: #132241
FCP for const_sockaddr_setters: #131714Fixes#132241Fixes#131714
Cc ``@rust-lang/wg-const-eval``
Improve the generic MIR in the default `PartialOrd::le` and friends
It looks like I regressed this accidentally in #137197 due to #137901
So this PR does two things:
1. Tweaks the way we're calling `is_some_and` so that it optimizes in the generic MIR (rather than needing to optimize it in every monomorphization) -- the first commit adds a MIR test, so you can see the difference in the second commit.
2. Updates the implementations of `is_le` and friends to be slightly simpler, and parallel how clang does them.
Fix crash in BufReader::peek()
`bufreader_peek` tracking issue: #128405
This fixes a logic error in `Buffer::read_more()` that would make `BufReader::peek()` expose uninitialized data and/or segfault if `read_more()` was called with a partially-full buffer and a non-empty inner reader.
Specialize `OsString::push` and `OsString as From` for UTF-8
When concatenating two WTF-8 strings, surrogate pairs at the boundaries need to be joined. However, since UTF-8 strings cannot contain surrogate halves, this check can be skipped when one string is UTF-8. Specialize `OsString::push` to use a more efficient concatenation in this case.
The WTF-8 version of `OsString` tracks whether it is known to be valid UTF-8 with its `is_known_utf8` field. Specialize `From<AsRef<OsStr>>` so this can be set for UTF-8 string types.
Unfortunately, a specialization for `T: AsRef<str>` conflicts with `T: AsRef<OsStr>`, so stamp out string types with a macro.
r? ``@ChrisDenton``
Override default `Write` methods for cursor-like types
Override the default `io::Write` methods for cursor-like types to provide more efficient versions.
Writes to resizable containers already write everything, so implement `write_all` and `write_all_vectored` in terms of those. For fixed-sized containers, cut out unnecessary error checking and looping for those same methods.
| `impl Write for T` | `vectored` | `all` | `all_vectored` | `fmt` |
| ------------------------------- | ---------- | ----- | -------------- | ------- |
| `&mut [u8]` | Y | Y | new | |
| `Vec<u8>` | Y | Y | new | #137762 |
| `VecDeque<u8>` | Y | Y | new | #137762 |
| `std::io::Cursor<&mut [u8]>` | Y | new | new | |
| `std::io::Cursor<&mut Vec<u8>>` | Y | new | new | #137762 |
| `std::io::Cursor<Vec<u8>>` | Y | new | new | #137762 |
| `std::io::Cursor<Box<[u8]>>` | Y | new | new | |
| `std::io::Cursor<[u8; N]>` | Y | new | new | |
| `core::io::BorrowedCursor<'_>` | new | new | new | |
Tracked in https://github.com/rust-lang/rust/issues/136756.
# Open questions
Is it guaranteed by `Write::write_all` that the maximal write is performed when not everything can be written? Its documentation describes the behavior of the default implementation, which writes until a 0-length write is encountered, thus implying that a maximal write is expected. In contrast, `Read::read_exact` declares that the contents of the buffer are unspecified for short reads. If it were allowed, these cursor-like types could bail on the write altogether if it has insufficient capacity.
Revert vita's c_char back to i8
# Description
Hi!
https://github.com/rust-lang/rust/pull/132975 changed the definition of `c_char` from i8 to u8 for most ARM targets. While that would usually be correct, [VITASDK uses signed chars by default](https://github.com/vitasdk/buildscripts/blob/master/patches/gcc/0001-gcc-10.patch#L33-L34). The Clang definitions are incorrect because Clang is not (yet?) supported by the vita commmunity / `VITADSK`, On the Rust side, the pre-compiled libraries the user can link to are all compiled using vita's `gcc` and [we set `TARGET_CC` and `TARGET_CXX`](d564a132cb/src/commands/build.rs (L230)) in `cargo vita` for build scripts using `cc`.
I'm creating it as a draft PR so that we can discuss it and possibly get it approved here, but wait to merge the [libc side](https://github.com/rust-lang/libc/pull/4258) and get a libc version first, as having the definitions out of sync breaks std. As a nightly-only target it can be confusing/frustrating for new users when the latest nightly, which is the default, is broken.
Use `std::mem::{size_of, size_of_val, align_of, align_of_val}` from the
prelude instead of importing or qualifying them.
These functions were added to all preludes in Rust 1.80.
Rollup of 17 pull requests
Successful merges:
- #137827 (Add timestamp to unstable feature usage metrics)
- #138041 (bootstrap and compiletest: Use `size_of_val` from the prelude instead of imported)
- #138046 (trim channel value in `get_closest_merge_commit`)
- #138053 (Increase the max. custom try jobs requested to `20`)
- #138061 (triagebot: add a `compiler_leads` ad-hoc group)
- #138064 (Remove - from xtensa targets cpu names)
- #138075 (Use final path segment for diagnostic)
- #138078 (Reduce the noise of bootstrap changelog warnings in --dry-run mode)
- #138081 (Move `yield` expressions behind their own feature gate)
- #138090 (`librustdoc`: flatten nested ifs)
- #138092 (Re-add `DynSend` and `DynSync` impls for `TyCtxt`)
- #138094 (a small borrowck cleanup)
- #138098 (Stabilize feature `const_copy_from_slice`)
- #138103 (Git ignore citool's target directory)
- #138105 (Fix broken link to Miri intrinsics in documentation)
- #138108 (Mention me (WaffleLapkin) when changes to `rustc_codegen_ssa` occur)
- #138117 ([llvm/PassWrapper] use `size_t` when building arg strings)
r? `@ghost`
`@rustbot` modify labels: rollup
Rollup of 25 pull requests
Successful merges:
- #135733 (Implement `&pin const self` and `&pin mut self` sugars)
- #135895 (Document workings of successors more clearly)
- #136922 (Pattern types: Avoid having to handle an Option for range ends in the type system or the HIR)
- #137303 (Remove `MaybeForgetReturn` suggestion)
- #137327 (Undeprecate env::home_dir)
- #137358 (Match Ergonomics 2024: add context and examples to the unstable book)
- #137534 ([rustdoc] hide item that is not marked as doc(inline) and whose src is doc(hidden))
- #137565 (Try to point of macro expansion from resolver and method errors if it involves macro var)
- #137637 (Check dyn flavor before registering upcast goal on wide pointer cast in MIR typeck)
- #137643 (Add DWARF test case for non-C-like `repr128` enums)
- #137744 (Re-add `Clone`-derive on `Thir`)
- #137758 (fix usage of ty decl macro fragments in attributes)
- #137764 (Ensure that negative auto impls are always applicable)
- #137772 (Fix char count in `Display` for `ByteStr`)
- #137798 (ci: use ubuntu 24 on arm large runner)
- #137802 (miri native-call support: all previously exposed provenance is accessible to the callee)
- #137805 (adjust Layout debug printing to match the internal field name)
- #137808 (Do not require that unsafe fields lack drop glue)
- #137820 (Clarify why InhabitedPredicate::instantiate_opt exists)
- #137825 (Provide more context on resolve error caused from incorrect RTN)
- #137834 (rustc_fluent_macro: use CARGO_CRATE_NAME instead of CARGO_PKG_NAME)
- #137868 (Add minimal platform support documentation for powerpc-unknown-linux-gnuspe)
- #137910 (Improve error message for `AsyncFn` trait failure for RPIT)
- #137920 (interpret/provenance_map: consistently use range_is_empty)
- #138038 (Update `compiler-builtins` to 0.1.151)
r? `@ghost`
`@rustbot` modify labels: rollup
Fix broken link to Miri intrinsics in documentation
This PR updates an outdated link in the library/core/src/intrinsics/mod.rs file. The previous link, pointing to the Miri repository's src/shims/intrinsics directory, has been replaced with the correct one: https://github.com/rust-lang/miri/tree/master/src/intrinsics. This ensures that users can access the appropriate resources for the relevant intrinsic functions.
Fix char count in `Display` for `ByteStr`
`ByteStr as Display` performs a byte count when a char count is required.
r? ```````````@joshtriplett```````````
Pattern types: Avoid having to handle an Option for range ends in the type system or the HIR
Instead,
1. during hir_ty_lowering, we now generate constants for the min/max when the range doesn't have a start/end specified.
2. in a later commit we generate those constants during ast lowering, simplifying everything further by not having to handle the range end inclusivity anymore in the type system (and thus avoiding any issues of `0..5` being different from `0..=4`
I think it makes all the type system code simpler, and the cost of the extra `ConstKind::Value` processing seems negligible.
r? `@BoxyUwU`
cc `@joshtriplett` `@scottmcm`
Document workings of successors more clearly
This is an attempt to fix#135087 together with https://github.com/rust-lang/rust/pull/135886, but I am not sure if I've succeeded in adding much clarity here, so don't be shy with your comments.
Various coretests improvements
The first commit is not yet strictly necessary as directly testing libcore works though useless work, but will be necessary once https://github.com/rust-lang/rust/pull/136642 migrates the liballoc tests into a separate package. The second commit fixes https://github.com/rust-lang/rust/issues/137478 and ensures that coretests actually gets tested on all CI job. The third commit fixes an error that didn't get caught because coretests doesn't run on the wasm32 CI job.
uefi: Add Service Binding Protocol abstraction
- Some UEFI protocols such as TCP4, TCP6, UDP4, UDP6, etc are managed by service binding protocol.
- A new instance of such protocols is created and destroyed using the corresponding service binding protocol.
- This PR adds abstractions to make using such protocols simpler using Rust Drop trait.
- The reason to add these abstractions in a seperate PR from TCP4 Protocol is to make review easier.
[EFI_SERVICE_BINDING_PROTCOL](https://uefi.org/specs/UEFI/2.11/11_Protocols_UEFI_Driver_Model.html#efi-service-binding-protocol)
cc ````@nicholasbishop````
[illumos] attempt to use posix_spawn to spawn processes
illumos has `posix_spawn`, and the very newest versions also have `_addchdir`, so use that. POSIX standardized this function so I also added a weak symbol lookup for the non `_np` version. (illumos has both.)
This probably also works on Solaris, but I don't have access to an installation to validate this so I decided to focus on illumos instead.
This is a nice ~4x performance improvement for process creation. My go-to as usual is nextest against the clap repo, which acts as a stress test for process creation -- with [this commit]:
```console
$ cargo nextest run -E 'not test(ui_tests) and not test(example_tests)'
before: Summary [ 1.747s] 879 tests run: 879 passed, 2 skipped
after: Summary [ 0.445s] 879 tests run: 879 passed, 2 skipped
```
[this commit]: fde45f9aea
Slightly reformat `std::fs::remove_dir_all` error docs
To make the error cases easier to spot on a quick glance, as I've been bitten by this a couple of times already 💀
cc #137230.
Count char width at most once in `Formatter::pad`
When both width and precision flags are specified, then `Formatter::pad` counts the character width twice. Instead, record the character width when truncating it to the precision, so it does not need to be recomputed. Simplify control flow so the cases are more clear.
Related:
- 6c9e708f4b (`fmt::Formatter::pad`: don't call chars().count() more than one time, 2021-09-01): Reduce counting chars from thrice to twice in worst case
- ede39aeb33 (feat: reinterpret `precision` field for strings, 2016-06-29): Change meaning of precision for strings
- b820748ff5 (Implement formatting arguments for strings and integers, 2013-08-10): Implement `Formatter::pad`
dec2flt: Clean up float parsing modules
This is the first portion of my work adding support for parsing and printing `f16`. Changes in `float.rs` replace the magic constants with expressions and add some use of generics to better support the new float types. Everything else is related to documentation or naming; there are no functional changes in this PR.
This can be reviewed by commit.
Update `compiler-builtins` to 0.1.149
Includes a change to make a subset of math symbols available on all platforms [1], and disables `f16` on aarch64 without neon [2].
[1]: https://github.com/rust-lang/compiler-builtins/pull/763
[2]: https://github.com/rust-lang/compiler-builtins/pull/775
try-job: aarch64-gnu
try-job: aarch64-gnu-debug
try-job: armhf-gnu
try-job: dist-various-1
try-job: dist-various-2
try-job: dist-aarch64-linux
try-job: dist-arm-linux
try-job: dist-armv7-linux
try-job: dist-x86_64-linux
try-job: test-various
Rollup of 12 pull requests
Successful merges:
- #135767 (Future incompatibility warning `unsupported_fn_ptr_calling_conventions`: Also warn in dependencies)
- #137852 (Remove layouting dead code for non-array SIMD types.)
- #137863 (Fix pretty printing of unsafe binders)
- #137882 (do not build additional stage on compiler paths)
- #137894 (Revert "store ScalarPair via memset when one side is undef and the other side can be memset")
- #137902 (Make `ast::TokenKind` more like `lexer::TokenKind`)
- #137921 (Subtree update of `rust-analyzer`)
- #137922 (A few cleanups after the removal of `cfg(not(parallel))`)
- #137939 (fix order on shl impl)
- #137946 (Fix docker run-local docs)
- #137955 (Always allow rustdoc-json tests to contain long lines)
- #137958 (triagebot.toml: Don't label `test/rustdoc-json` as A-rustdoc-search)
r? `@ghost`
`@rustbot` modify labels: rollup
Disable `f16` on Aarch64 without `neon`
LLVM has crashes at some `half` operations when built with assertions enabled if fp-armv8 is not available [1]. Things seem to usually work, but we are reaching LLVM undefined behavior so this needs to be disabled.
[1]: https://github.com/llvm/llvm-project/issues/129394
More precisely document `Global::deallocate()`'s safety.
There is a subtlety which "other conditions must be upheld by the caller" does not capture: `GlobalAlloc`/`alloc::dealloc()` require that the provided layout will be *equal*, not just that it "fits", the layout used to allocate. This is always true here due to how `allocate()`, `grow()`, and `shrink()` are implemented (they never return a larger allocation than requested), but that is a non-local property of the implementation, so it should be documented explicitly.
r? libs
`@rustbot` label A-allocators
Minor internal comments fix for `BufRead::read_line`
Just a little fix that came up while I was reading through this source code, and had to search for a few minutes to find out what was actually *meant* here.
A lot of the magic constants can be turned into expressions. This
reduces some code duplication.
Additionally, add traits to make these operations fully generic. This
will make it easier to support `f16` and `f128`.
The previous commit renamed `Decimal` to `DecimalSeq`. Now, rename the
type that represents a decimal floating point number to be `Decimal`.
Additionally, add some tests for internal behavior.
This module currently contains two decimal types, `Decimal` and
`Number`. These names don't provide a whole lot of insight into what
exactly they are, and `Number` is actually the one that is more like an
expected `Decimal` type.
In accordance with this, rename the existing `Decimal` to `DecimalSeq`.
This highlights that it contains a sequence of decimal digits, rather
than representing a base-10 floating point (decimal) number.
Additionally, add some tests to validate internal behavior.
LLVM has crashes at some `half` operations when built with assertions
enabled if fp-armv8 is not available [1]. Things seem to usually work,
but we are reaching LLVM undefined behavior so this needs to be
disabled.
[1]: https://github.com/llvm/llvm-project/issues/129394
- Some UEFI protocols such as TCP4, TCP6, UDP4, UDP6, etc are managed by
service binding protocol.
- A new instance of such protocols is created and destroyed using the
corresponding service binding protocol.
- This PR adds abstractions to make using such protocols simpler using
Rust Drop trait.
- The reason to add these abstractions in a seperate PR from TCP4
Protocol is to make review easier.
[EFI_SERVICE_BINDING_PROTCOL](https://uefi.org/specs/UEFI/2.11/11_Protocols_UEFI_Driver_Model.html#efi-service-binding-protocol)
Signed-off-by: Ayush Singh <ayush@beagleboard.org>
Fix inaccurate `std::intrinsics::simd` documentation
This addresses two issues:
- the docs on comparison operators (`simd_gt` etc.) said they only work for floating-point vectors, but they work for integer vectors too.
- the docs on various functions that use a mask did not document that the mask must be a signed integer vector. Unsigned integer vectors would cause invalid behavior when the mask vector is widened (unsigned integers would use zero extension, producing incorrect results).
r? ``@workingjubilee``
Use correct error message casing for `io::const_error`s
Error messages are supposed to start with lowercase letters, but a lot of `io::const_error` messages did not. This fixes them to start with a lowercase letter.
I did consider adding a const check for this to the macro, but some of them start with proper nouns that make sense to uppercase them.
See https://doc.rust-lang.org/1.85.0/std/error/trait.Error.html
Buffer::read_more() is supposed to refill the buffer without discarding
its contents, which are in the range `pos .. filled`.
It mistakenly borrows the range `pos ..`, fills that, and then
increments `filled` by the amount read. This overwrites the buffer's
existing contents and sets `filled` to a too-large value that either
exposes uninitialized bytes or walks off the end of the buffer entirely.
This patch makes it correctly fill only the unfilled portion of the
buffer, which should maintain all the type invariants and fix the test
failure introduced in commit b1196717fc.
This patch makes BufReader::peek()'s doctest call read_more() to refill
the buffer before the inner reader hits EOF. This exposes a bug in
read_more() that causes an out-of-bounds slice access and segfault.
The WTF-8 version of `OsString` tracks whether it is known to be valid
UTF-8 with its `is_known_utf8` field. Specialize `From<AsRef<OsStr>>` so
this can be set for UTF-8 string types.
When concatenating two WTF-8 strings, surrogate pairs at the boundaries
need to be joined. However, since UTF-8 strings cannot contain surrogate
halves, this check can be skipped when one string is UTF-8. Specialize
`OsString::push` to use a more efficient concatenation in this case.
Unfortunately, a specialization for `T: AsRef<str>` conflicts with
`T: AsRef<OsStr>`, so stamp out string types with a macro.
Error messages are supposed to start with lowercase letters, but a lot
of `io::const_error` messages did not. This fixes them to start with a
lowercase letter.
I did consider adding a const check for this to the macro, but some of
them start with proper nouns that make sense to uppercase them.
See https://doc.rust-lang.org/1.85.0/std/error/trait.Error.html
Fix Windows `Command` search path bug
Currently `Command::new` on Windows works differently depending on whether any environment variable is set. For example,
```rust
// Searches for "myapp" in the application and system paths first (aka Windows native behaviour).
Command::new("myapp").spawn();
// Search for "myapp" in `PATH` first
Command::new("myapp").env("a", "b").spawn();
```
This is a bug because the search path should only change if `PATH` is changed for the child (i.e. `.env("PATH", "...")`).
This was discussed in a libs-api meeting where the exact semantics of `Command::new` was not decided but there seemed to be broad agreement that this particular thing is just a bug that can be fixed.
r? libs-api
import `simd_` intrinsics
In most cases, we can import the simd intrinsics rather than redeclare them. Apparently, most of these tests were written before `std::intrinsics::simd` existed.
There are a couple of exceptions where we can't yet import:
- the intrinsics are not declared as `const fn` in the standard library, causing issues in the `const-eval` tests
- the `simd_shuffle_generic` function is not exposed from `std::intrinsics`
- the `simd_fpow` and `simd_fpowi` functions are not exposed from `std::intrinsics` (removed in https://github.com/rust-lang/rust/pull/137595)
- some tests use `no_core`, and therefore cannot use `std::intrinsics`
r? ```@RalfJung```
cc ```@workingjubilee``` do you have context on why some intrinsics are not exposed?
Update some comparison codegen tests now that they pass in LLVM20
Fixes#106107
Needed one tweak to the default `PartialOrd::le` to get the test to pass. Everything but the derived 2-field `le` test passes even without the change to the defaults in the trait.
When both width and precision flags are specified, then the character
width is counted twice. Instead, record the character width when
truncating it to the precision, so it does not need to be recomputed.
Simplify control flow so the cases are more clear.
Return unexpected termination error instead of panicing in `Thread::join`
There is a time window during which the OS can terminate a thread before stdlib can retreive its `Packet`. Currently the `Thread::join` panics with no message in such an event, which makes debugging difficult; fixes#124466.
Add UTF-8 validation fast paths in `Wtf8Buf`
This adds two more fast paths for UTF-8 validation in `Wtf8Buf`, making use of the `is_known_utf8` flag added in https://github.com/rust-lang/rust/pull/96869 (Optimize `Wtf8Buf::into_string` for the case where it contains UTF-8).
r? `@ChrisDenton`
There is a subtlety which "other conditions must be upheld by the caller"
does not capture: `GlobalAlloc`/`alloc::dealloc()` require that the
provided layout will be *equal*, not just that it "fits", the layout
used to allocate. This is always true here due to how `allocate()`,
`grow()`, and `shrink()` are implemented (they never return a larger
allocation than requested), but that is a non-local property of the
implementation, so it should be documented explicitly.
Rollup of 8 pull requests
Successful merges:
- #137370 (adjust_abi: make fallback logic for ABIs a bit easier to read)
- #137444 (Improve behavior of `IF_LET_RESCOPE` around temporaries and place expressions)
- #137464 (Fix invalid suggestion from type error for derive macro)
- #137539 ( Add rustdoc-gui regression test for #137082 )
- #137576 (Don't doc-comment BTreeMap<K, SetValZST, A>)
- #137595 (remove `simd_fpow` and `simd_fpowi`)
- #137600 (type_ir: remove redundant part of comment)
- #137602 (feature: fix typo in attribute description)
r? `@ghost`
`@rustbot` modify labels: rollup
Don't doc-comment BTreeMap<K, SetValZST, A>
This otherwise shows up in documentation as an empty impl block (worse, at the *top* of the docs above the public impls).
remove `#[rustc_intrinsic_must_be_overridde]`
In https://github.com/rust-lang/rust/pull/135031, we gained support for just leaving away the body. Now that the bootstrap compiler got bumped, stop using the old style and remove support for it.
r? `@oli-obk`
There are a few more mentions of this attribute in RA code that I didn't touch; Cc `@rust-lang/rust-analyzer`
remove some unnecessary rustc_const_unstable
If the function is anyway unstable, it doesn't need to be `rustc_const_unstable`.
`copy_from_slice` turns out to not do anything const-unstable itself, we just haven't stably committed to it being available in const yet. See [here](https://rustc-dev-guide.rust-lang.org/stability.html?highlight=rustc_const_stable_indirect) for more details on the `rustc_const_stable_indirect` attribute.
Implement `read_buf` for zkVM stdin
For the zkVM, even when a guest buffer is uninitialized, from the host's perspective it is just a normal piece of memory which was initialized before letting the guest write into it. This makes `sys_read` safe to use with an uninitialized buffer. See https://github.com/risc0/risc0/issues/2853.
cc `@bobbobbio,` `@flaub`
r? `@Noratrieb`
Tracked in https://github.com/rust-lang/rust/issues/136756
Update `String::from_raw_parts` safety requirements
These have become out of sync with `Vec::from_raw_part`'s safety requirements, and are likely to diverge again. I think it's safest to just point at `Vec`'s requirements.
https://github.com/rust-lang/rust/issues/119206#issuecomment-2180116680
Windows: use existing wrappers in `File::open_native`
Just a small improvement I've noticed - prevents accidents regarding `SetFileInformationByHandle` parameters.
Probably ``@ChrisDenton`` since we talked about it on discord :)
Unstable `gen_future` Feature Tracking
This PR removes the reference to the closed tracking issue **#50547** for the `gen_future` feature. Since `gen_future` is an internal feature used in async block desugaring, it does not require a public tracking issue.
#### Changes:
- Replaced `issue = "50547"` with `issue = "none"` in **library/core/src/future/mod.rs**.
- Ensures that it is correctly identified as an internal feature.
#### Rationale:
With this change, the Unstable Book will now state:
> *"This feature has no tracking issue and is therefore likely internal to the compiler, not being intended for general use."*
Closes **#76249**. 🚀🦀
Fixed issue with usage of generics and moved feature gate to crate root
Removed const tag
Fixed alphabetical ordering of feature gate, added same to doctest
Removed crate-level declaration of feature gate control_flow_into_value
Used const_precise_live_drops to constify into_value without issue of a drop
intrinsics: unify rint, roundeven, nearbyint in a single round_ties_even intrinsic
LLVM has three intrinsics here that all do the same thing (when used in the default FP environment). There's no reason Rust needs to copy that historically-grown mess -- let's just have one intrinsic and leave it up to the LLVM backend to decide how to lower that.
Suggested by `@hanna-kruppe` in https://github.com/rust-lang/rust/issues/136459; Cc `@tgross35`
try-job: test-various
