Don't fuse in `MapWindows`
cc https://github.com/rust-lang/rust/issues/87155
Fusing makes the iterator larger, slower, more complicated, and less useful. Users who need fusing behavior can always use `.fuse()`, but there is no way to get non-fusing behavior from the fused version.
@rustbot label A-iterators
simd_fmin/fmax: make semantics and name consistent with scalar intrinsics
This is the SIMD version of https://github.com/rust-lang/rust/pull/153343: change the documented semantics of the SIMD float min/max intrinsics to that of the scalar intrinsics, and also make the name consistent. The overall semantic change this amounts to is that we restrict the non-determinism: the old semantics effectively mean "when one input is an SNaN, the result non-deterministically is a NaN or the other input"; the new semantics say that in this case the other input must be returned. For all other cases, old and new semantics are equivalent. This means all users of these intrinsics that were correct with the old semantics are still correct: the overall set of possible behaviors has become smaller, no new possible behaviors are being added.
In terms of providers of this API:
- Miri, GCC, and cranelift already implement the new semantics, so no changes are needed.
- LLVM is adjusted to use `minimumnum nsz` instead of `minnum`, thus giving us the new semantics.
In terms of consumers of this API:
- Portable SIMD almost certainly wants to match the scalar behavior, so this is strictly a bugfix here.
- Stdarch mostly stopped using the intrinsic, except on nvptx, where arguably the new semantics are closer to what we actually want than the old semantics (https://github.com/rust-lang/stdarch/issues/2056).
Q: Should there be an `f` in the intrinsic name to indicate that it is for floats? E.g., `simd_fminimum_number_nsz`?
Also see https://github.com/rust-lang/rust/issues/153395.
Merge `fabsf16/32/64/128` into `fabs::<F>`
Following [a small conversation on Zulip](https://rust-lang.zulipchat.com/#narrow/channel/131828-t-compiler/topic/Float.20intrinsics/with/521501401) (and because I'd be interested in starting to contribute on Rust), I thought I'd give a try at merging the float intrinsics :)
This PR just merges `fabsf16`, `fabsf32`, `fabsf64`, `fabsf128`, as it felt like an easy first target.
Notes:
- I'm opening the PR for one intrinsic as it's probably easier if the shift is done one intrinsic at a time, but let me know if you'd rather I do several at a time to reduce the number of PRs.
- Currently this PR increases LOCs, despite being an attempt at simplifying the intrinsics/compilers. I believe this increase is a one time thing as I had to define new functions and move some things around, and hopefully future PRs/commits will reduce overall LoCs
- `fabsf32` and `fabsf64` are `#[rustc_intrinsic_const_stable_indirect]`, while `fabsf16` and `fabsf128` aren't; because `f32`/`f64` expect the function to be const, the generic version must be made indirectly stable too. We'd need to check with T-lang this change is ok; the only other intrinsics where there is such a mismatch is `minnum`, `maxnum` and `copysign`.
- I haven't touched libm because I'm not familiar with how it works; any guidance would be welcome!
stabilizes `core::range::RangeFrom`
stabilizes `core::range::RangeFromIter`
add examples for `remainder` method on range iterators
`RangeFromIter::remainder` was not stabilized (see issue 154458)
Make `Ipv6Addr::multicast_scope()` exhaustive
And make `Ipv6MulticastScope` exhaustive, with `repr(u8)` and the proper discriminant values. The variants for the two reserved scopes are gated behind a perma-unstable feature, in order to avoid committing to names for them.
[IETF RFC 4291](https://datatracker.ietf.org/doc/html/rfc4291#section-2.7) and [IETF RFC 7346](https://datatracker.ietf.org/doc/html/rfc7346#section-2) define the list of multicast scopes. The former document says:
> scopes labeled "(unassigned)" are available for administrators to define additional multicast regions.
Tracking issue: https://github.com/rust-lang/rust/issues/27709
@rustbot label A-io
simd_add/sub/mul/neg: document overflow behavior
`simd_neg` had an odd comment about overflow not being UB, without saying what the behavior is instead. Replace that by just saying this uses wrapping arithmetic, and add the same for add/sub/mul. div/rem are already documented to cause UB on div-by-zero and min-div-by-minus-one, and shl/shr cause UB on too large shift amounts.
Also, delete impls on non-Deref types.
Pin doesn't do anything useful for non-Deref types, so PinCoerceUnsized
on such types makes no sense.
This is a breaking change, since stable code can observe the deleted
`PinCoerceUnsized` impls by uselessly coercing between such types
inside a `Pin`.
There is still some strange behavior, such as `Pin<&mut i32>` being
able to coerce to `Pin<&dyn Send>`, but not being able to coerce to
`Pin<&i32>`. However, I don't think it's possible to fix this.
Fixes https://github.com/rust-lang/rust/issues/145081
Defer codegen for the VaList Drop impl to actual uses
This allows compiling libcore with codegen backends that don't actually implement VaList like cg_clif.
And make `Ipv6MulticastScope` exhaustive,
with `repr(u8)` and the proper discriminant values.
The variants for the two reserved scopes
are gated behind a perma-unstable feature,
in order to avoid committing to names for them.
[IETF RFC 4291](https://datatracker.ietf.org/doc/html/rfc4291#section-2.7)
and [IETF RFC 7346](https://datatracker.ietf.org/doc/html/rfc7346#section-2)
define the list of multicast scopes.
The former document says:
> scopes labeled "(unassigned)" are available for administrators
> to define additional multicast regions.
Add APIs for dealing with titlecase
ACP: https://github.com/rust-lang/libs-team/issues/354
Tracking issue: https://github.com/rust-lang/rust/issues/153892
r? libs-api
@rustbot label T-libs -T-libs-api A-unicode
~~The last commit has some insta-stable `PartialEq` impls, therefore: @rustbot label -needs-fcp
Alternatively, I could split those out into a follow-up PR.~~ (Edit: will do in follow-up)
Lifted intersperse and intersperse_with Fused transformation and updated documentation + tests
This PR once again builds on top of rust-lang/rust#152855. From the discussion in rust-lang/rust#152855, libs team came to the conclusion that `intersperse`/`intersperse_with` shouldn't transform the given iterator to a fused iterator always and a separator should be emitted between `Some(_)` items for non fused iterators (particularly just right before the subsequent `Some(_)`).
On top of the change Zakarumych added in the PR, I lifted the `FusedIterator` trait and transformation of the inner `iter` for `Intersperse`/`IntersperseWith`, so that we can display this behavior. I've adjusted the documentation and tests accordingly to reflect this change as well.
r? @jhpratt
refactor RangeFromIter overflow-checks impl
Crates with different overflow-checks settings accessing the same RangeFromIter resulted in incorrect values being yielded
Fixesrust-lang/rust#154124
r? @tgross35
We've already stabilized float operations in const,
which means we've already accepted that a `const fn`
might behave differently in consteval vs at run time.
don't suggest non-deriveable traits for unions
Fixesrust-lang/rust#137587
Before, the compiler suggested adding `#[derive(Debug)]` (other traits too) for unions,
which is misleading because some traits can't be automatically derived.
Only traits that are still suggested are Copy and Clone.
I noticed the error label changed after removing the suggestion. I hope this isn't a big deal, but let me know if that's an issue.
original example:
```rs
union Union {
member: usize,
}
impl PartialEq<u8> for Union {
fn eq(&self, rhs: &u8) -> bool {
unsafe { self.member == (*rhs).into() }
}
}
fn main() {
assert_eq!(Union { member: 0 }, 0);
}
```
before:
```
error[E0277]: `Union` doesn't implement `Debug`
--> src\main.rs:13:5
|
13 | assert_eq!(Union { member: 0 }, 0);
| ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^ the trait `Debug` is not implemented for `Union`
|
= note: add `#[derive(Debug)]` to `Union` or manually `impl Debug for Union`
= note: this error originates in the macro `assert_eq` (in Nightly builds, run with -Z macro-backtrace for more info)
help: consider annotating `Union` with `#[derive(Debug)]`
|
2 + #[derive(Debug)]
3 | union Union {
|
```
after (the message doesn't suggest adding #[derive(Debug)] to unions)
```
error[E0277]: `Union` doesn't implement `Debug`
--> src\main.rs:13:5
|
13 | assert_eq!(Union { member: 0 }, 0);
| ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^ unsatisfied trait bound
|
help: the trait `Debug` is not implemented for `Union`
--> src\main.rs:2:1
|
2 | union Union {
| ^^^^^^^^^^^
= note: manually `impl Debug for Union`
```
two smaller feature cleanups
Remove an unneeded feature gate for a private macro and sort the used features correctly by whether they are language or library features.
Derive Macro Eq: link to more detailed documentation
Match the other derive macros in the module (Ord, PartialEq, PartialOrd) by linking to the section in the trait documentation about how the derive macro works.
Split the `dec2flt::RawFloat` trait for easier reuse
`RawFloat` is an internal trait with quite a few useful float properties. It currently resides in the `dec2flt` module but is also used in parsing, and would be nice to reuse other places. Unfortunately it cannot be implemented on `f128` because of limitations with how the parsing API is implemented (mantissa must fit into a u64).
To make the trait easier to work with, split it into the following:
* `Float`: Anything that is reasonably applicable to all floating point types.
* `FloatExt`: Items that should be part of `Float` but don't work for all float types. This will eventually be merged back into `Float` once it can be implemented on f128.
* `Lemire`: Items that are specific to the Lemire dec2flt algorithm.
These traits are then moved to places that make sense.
Builds on top of https://github.com/rust-lang/rust/pull/151900
Optimize 128-bit integer formatting
The compiler is unaware of the restricted range of the input, so it is unable to optimize out the final division and modulus. By doing this manually, we get a nontrivial performance gain.
r? @dtolnay
(copied from https://github.com/dtolnay/itoa/pull/68)
Add missing `track_caller` to overflowing trait methods
Fixesrust-lang/rust#152599 by adding `#[track_caller]` to arithmetic trait methods (`Neg`, `Shl`, `ShlAssign`, `Shr` and `ShrAssign`) so overflow panics report the correct call site instead of the trait definition.
bors