feat: update stdarch submodule for intrinsics on ARM
Submodule update for stdarch library
10 commits in c0257c1660e78c80ad1b9136fcc5555b14da5b4c..df3618d9f35165f4bc548114e511c49c29e1fd9b
2024-04-22 01:24:03 +0200 to 2024-05-14 15:52:07 +0200
- feat: stabilization for stdarch_aarch64_crc32
- Add vec_insert and vec_extract
- Remove libc dependency on Windows by using Win32 to get env vars
- Add vec_orc
- Simplify vec_andc implementation
- Silence unexpected-cfgs
- Add vec_mul
- Remove `#![feature(inline_const)]`
- Add `#[cfg_attr(miri, ignore)]` to tests of intrinsics that cannot be supported by Miri
- Implement ARM `__ssat` and `__usat` functions
r? Amanieu
Re-add `From<f16> for f64`
This impl was originally added in #122470 before being removed in #123830 due to #123831. However, the issue only affects `f32` (which currently only has one `From<{float}>` impl, `From<f32>`) as `f64` already has two `From<{float}>` impls (`From<f32>` and `From<f64>`) and is also the float literal fallback type anyway. Therefore it is safe to re-add `From<f16> for f64`.
This PR also updates the FIXME link to point to the open issue #123831 rather than the closed issue #123824.
Tracking issue: #116909
`@rustbot` label +F-f16_and_f128 +T-libs-api
Refactor examples and enhance documentation in result.rs
- Replaced `map` with `map_err` in the error handling example for correctness
- Reordered example code to improve readability and logical flow
- Added assertions to examples to demonstrate expected outcomes
Invert comparison in `uN::checked_sub`
After #124114, LLVM no longer combines the comparison and subtraction in `uN::checked_sub` when either operand is a constant (demo: https://rust.godbolt.org/z/MaeoYbsP1). The difference is more pronounced when the expression is slightly more complex (https://rust.godbolt.org/z/4rPavsYdc).
This is due to the use of `>=` here:
ee97564e3a/library/core/src/num/uint_macros.rs (L581-L593)
For constant `C`, LLVM eagerly converts `a >= C` into `a > C - 1`, but the backend can only combine `a < C` with `a - C`, not `C - 1 < a` and `a - C`: e586556e37/llvm/lib/CodeGen/CodeGenPrepare.cpp (L1697-L1742)
This PR[^1] simply inverts the `>=` into `<` to restore the LLVM magic, and somewhat align this with the implementation of `uN::overflowing_sub` from #103299.
When the result is stored as an `Option` (rather than being branched/cmoved on), the discriminant is `self >= rhs`. This PR doesn't affect the codegen (and relevant tests) of that since LLVM will negate `self < rhs` to `self >= rhs` when necessary.
[^1]: Note to `self`: My very first contribution to publicly-used code. Hopefully like what I should learn to always be, tiny and humble.
This is likely never intended and potentially a security vulnerability
if it happens.
I'd guess that it's mostly literal strings that are passed to this
function in practice, so I'm guessing this doesn't break anyone.
CC #125060
Update reference safety requirements
Per https://github.com/rust-lang/rust/pull/116677#issuecomment-1945495786, the language as written promises too much. This PR relaxes the language to be consistent with current semantics. If and when #117945 is implemented, we can revert to the old language.
While we're here, we also require that references be non-null.
cc ``@RalfJung``
std::alloc: use posix_memalign instead of memalign on solarish
`memalign` on Solarish requires the alignment to be at least the size of a pointer, which we did not honor. `posix_memalign` also requires that, but that code path already takes care of this requirement.
close GH-124787
Relax allocator requirements on some Rc/Arc APIs.
Split out from #119761
* Remove `A: Clone` bound from `Rc::assume_init`(s), `Rc::downcast`, and `Rc::downcast_unchecked` (`Arc` methods were already relaxed by #120445)
* Make `From<Rc<[T; N]>> for Rc<[T]>` allocator-aware (`Arc`'s already is).
* Remove `A: Clone` from `Rc/Arc::unwrap_or_clone`
Internal changes:
* Made `Arc::internal_into_inner_with_allocator` method into `Arc::into_inner_with_allocator` associated fn.
* Add private `Rc::into_inner_with_allocator` (to match Arc), so other fns don't have to juggle `ManuallyDrop`.
Document proper usage of `fmt::Error` and `fmt()`'s `Result`.
I've seen several newcomers wonder why `fmt::Error` doesn't have any error detail information, or propose to return it in response to an error condition found inside a `impl fmt::Display for MyType`.
That is incorrect, per [a lone paragraph of the `fmt` module's documentation](https://doc.rust-lang.org/1.78.0/std/fmt/index.html#formatting-traits). However, users looking to implement a formatting trait won't necessarily look there. Therefore, let's add the critical information (that formatting per se is infallible) to all the involved items: every `fmt()` method, and `fmt::Error`.
This PR is not intended to make any novel claims about `fmt`; only to repeat an existing one in places where it will be more visible.
Fix typo in ManuallyDrop's documentation
```diff
- /// A wrapper to inhibit compiler from automatically calling `T`’s destructor.
+ /// A wrapper to inhibit the compiler from automatically calling `T`’s destructor.
```
Remove feature from documentation examples
Add rustc_const_stable attribute to stabilized functions
Update intra-doc link for `u8::is_ascii_whitespace` on `&[u8]` functions
