Tracking Issue for `#![feature(const_float_methods)]` #130843

eduardosm · 2024-09-25T17:03:50Z

Feature gate: #![feature(const_float_methods)]

This is a tracking issue for making const some methods of floating point types.

Public API

// in `core`
impl <float> {
    pub const fn recip(self) -> Self;
    pub const fn to_degrees(self) -> Self;
    pub const fn to_radians(self) -> Self;
    pub const fn max(self, other: Self) -> Self;
    pub const fn min(self, other: Self) -> Self;
    pub const fn clamp(self, min: Self, max: Self) -> Self;
    pub const fn abs(self) -> Self;
    pub const fn signum(self) -> Self;
    pub const fn copysign(self, sign: Self) -> Self;
}

Steps / History

Implementation: Make some float methods unstable const fn #130568
Final comment period (FCP)¹
Stabilization PR

Unresolved Questions

None yet.

https://std-dev-guide.rust-lang.org/feature-lifecycle/stabilization.html ↩

The text was updated successfully, but these errors were encountered:

…alfJung,tgross35 Make some float methods unstable `const fn` Some float methods are now `const fn` under the `const_float_methods` feature gate. I also made some unstable methods `const fn`, keeping their constness under their respective feature gate. In order to support `min`, `max`, `abs` and `copysign`, the implementation of some intrinsics had to be moved from Miri to rustc_const_eval (cc `@RalfJung).` Tracking issue: rust-lang#130843 ```rust impl <float> { // #[feature(const_float_methods)] pub const fn recip(self) -> Self; pub const fn to_degrees(self) -> Self; pub const fn to_radians(self) -> Self; pub const fn max(self, other: Self) -> Self; pub const fn min(self, other: Self) -> Self; pub const fn clamp(self, min: Self, max: Self) -> Self; pub const fn abs(self) -> Self; pub const fn signum(self) -> Self; pub const fn copysign(self, sign: Self) -> Self; // #[feature(float_minimum_maximum)] pub const fn maximum(self, other: Self) -> Self; pub const fn minimum(self, other: Self) -> Self; // Only f16/f128 (f32/f64 already const) pub const fn is_sign_positive(self) -> bool; pub const fn is_sign_negative(self) -> bool; pub const fn next_up(self) -> Self; pub const fn next_down(self) -> Self; } ``` r? libs-api

…alfJung,tgross35 Make some float methods unstable `const fn` Some float methods are now `const fn` under the `const_float_methods` feature gate. I also made some unstable methods `const fn`, keeping their constness under their respective feature gate. In order to support `min`, `max`, `abs` and `copysign`, the implementation of some intrinsics had to be moved from Miri to rustc_const_eval (cc ``@RalfJung).`` Tracking issue: rust-lang#130843 ```rust impl <float> { // #[feature(const_float_methods)] pub const fn recip(self) -> Self; pub const fn to_degrees(self) -> Self; pub const fn to_radians(self) -> Self; pub const fn max(self, other: Self) -> Self; pub const fn min(self, other: Self) -> Self; pub const fn clamp(self, min: Self, max: Self) -> Self; pub const fn abs(self) -> Self; pub const fn signum(self) -> Self; pub const fn copysign(self, sign: Self) -> Self; // #[feature(float_minimum_maximum)] pub const fn maximum(self, other: Self) -> Self; pub const fn minimum(self, other: Self) -> Self; // Only f16/f128 (f32/f64 already const) pub const fn is_sign_positive(self) -> bool; pub const fn is_sign_negative(self) -> bool; pub const fn next_up(self) -> Self; pub const fn next_down(self) -> Self; } ``` r? libs-api

…alfJung,tgross35 Make some float methods unstable `const fn` Some float methods are now `const fn` under the `const_float_methods` feature gate. I also made some unstable methods `const fn`, keeping their constness under their respective feature gate. In order to support `min`, `max`, `abs` and `copysign`, the implementation of some intrinsics had to be moved from Miri to rustc_const_eval (cc ```@RalfJung).``` Tracking issue: rust-lang#130843 ```rust impl <float> { // #[feature(const_float_methods)] pub const fn recip(self) -> Self; pub const fn to_degrees(self) -> Self; pub const fn to_radians(self) -> Self; pub const fn max(self, other: Self) -> Self; pub const fn min(self, other: Self) -> Self; pub const fn clamp(self, min: Self, max: Self) -> Self; pub const fn abs(self) -> Self; pub const fn signum(self) -> Self; pub const fn copysign(self, sign: Self) -> Self; // #[feature(float_minimum_maximum)] pub const fn maximum(self, other: Self) -> Self; pub const fn minimum(self, other: Self) -> Self; // Only f16/f128 (f32/f64 already const) pub const fn is_sign_positive(self) -> bool; pub const fn is_sign_negative(self) -> bool; pub const fn next_up(self) -> Self; pub const fn next_down(self) -> Self; } ``` r? libs-api

Make some float methods unstable `const fn` Some float methods are now `const fn` under the `const_float_methods` feature gate. I also made some unstable methods `const fn`, keeping their constness under their respective feature gate. In order to support `min`, `max`, `abs` and `copysign`, the implementation of some intrinsics had to be moved from Miri to rustc_const_eval (cc `@RalfJung).` Tracking issue: rust-lang#130843 ```rust impl <float> { // #[feature(const_float_methods)] pub const fn recip(self) -> Self; pub const fn to_degrees(self) -> Self; pub const fn to_radians(self) -> Self; pub const fn max(self, other: Self) -> Self; pub const fn min(self, other: Self) -> Self; pub const fn clamp(self, min: Self, max: Self) -> Self; pub const fn abs(self) -> Self; pub const fn signum(self) -> Self; pub const fn copysign(self, sign: Self) -> Self; // #[feature(float_minimum_maximum)] pub const fn maximum(self, other: Self) -> Self; pub const fn minimum(self, other: Self) -> Self; // Only f16/f128 (f32/f64 already const) pub const fn is_sign_positive(self) -> bool; pub const fn is_sign_negative(self) -> bool; pub const fn next_up(self) -> Self; pub const fn next_down(self) -> Self; } ``` r? libs-api try-job: dist-s390x-linux

…alfJung,tgross35 Make some float methods unstable `const fn` Some float methods are now `const fn` under the `const_float_methods` feature gate. I also made some unstable methods `const fn`, keeping their constness under their respective feature gate. In order to support `min`, `max`, `abs` and `copysign`, the implementation of some intrinsics had to be moved from Miri to rustc_const_eval (cc `@RalfJung).` Tracking issue: rust-lang#130843 ```rust impl <float> { // #[feature(const_float_methods)] pub const fn recip(self) -> Self; pub const fn to_degrees(self) -> Self; pub const fn to_radians(self) -> Self; pub const fn max(self, other: Self) -> Self; pub const fn min(self, other: Self) -> Self; pub const fn clamp(self, min: Self, max: Self) -> Self; pub const fn abs(self) -> Self; pub const fn signum(self) -> Self; pub const fn copysign(self, sign: Self) -> Self; // #[feature(float_minimum_maximum)] pub const fn maximum(self, other: Self) -> Self; pub const fn minimum(self, other: Self) -> Self; // Only f16/f128 (f32/f64 already const) pub const fn is_sign_positive(self) -> bool; pub const fn is_sign_negative(self) -> bool; pub const fn next_up(self) -> Self; pub const fn next_down(self) -> Self; } ``` r? libs-api try-job: dist-s390x-linux

Rollup merge of rust-lang#130568 - eduardosm:const-float-methods, r=RalfJung,tgross35 Make some float methods unstable `const fn` Some float methods are now `const fn` under the `const_float_methods` feature gate. I also made some unstable methods `const fn`, keeping their constness under their respective feature gate. In order to support `min`, `max`, `abs` and `copysign`, the implementation of some intrinsics had to be moved from Miri to rustc_const_eval (cc `@RalfJung).` Tracking issue: rust-lang#130843 ```rust impl <float> { // #[feature(const_float_methods)] pub const fn recip(self) -> Self; pub const fn to_degrees(self) -> Self; pub const fn to_radians(self) -> Self; pub const fn max(self, other: Self) -> Self; pub const fn min(self, other: Self) -> Self; pub const fn clamp(self, min: Self, max: Self) -> Self; pub const fn abs(self) -> Self; pub const fn signum(self) -> Self; pub const fn copysign(self, sign: Self) -> Self; // #[feature(float_minimum_maximum)] pub const fn maximum(self, other: Self) -> Self; pub const fn minimum(self, other: Self) -> Self; // Only f16/f128 (f32/f64 already const) pub const fn is_sign_positive(self) -> bool; pub const fn is_sign_negative(self) -> bool; pub const fn next_up(self) -> Self; pub const fn next_down(self) -> Self; } ``` r? libs-api try-job: dist-s390x-linux

…gross35 Make some float methods unstable `const fn` Some float methods are now `const fn` under the `const_float_methods` feature gate. I also made some unstable methods `const fn`, keeping their constness under their respective feature gate. In order to support `min`, `max`, `abs` and `copysign`, the implementation of some intrinsics had to be moved from Miri to rustc_const_eval (cc `@RalfJung).` Tracking issue: rust-lang/rust#130843 ```rust impl <float> { // #[feature(const_float_methods)] pub const fn recip(self) -> Self; pub const fn to_degrees(self) -> Self; pub const fn to_radians(self) -> Self; pub const fn max(self, other: Self) -> Self; pub const fn min(self, other: Self) -> Self; pub const fn clamp(self, min: Self, max: Self) -> Self; pub const fn abs(self) -> Self; pub const fn signum(self) -> Self; pub const fn copysign(self, sign: Self) -> Self; // #[feature(float_minimum_maximum)] pub const fn maximum(self, other: Self) -> Self; pub const fn minimum(self, other: Self) -> Self; // Only f16/f128 (f32/f64 already const) pub const fn is_sign_positive(self) -> bool; pub const fn is_sign_negative(self) -> bool; pub const fn next_up(self) -> Self; pub const fn next_down(self) -> Self; } ``` r? libs-api try-job: dist-s390x-linux

RalfJung · 2024-11-12T06:55:53Z

@rust-lang/libs-api @rust-lang/wg-const-eval these all have fairly simple implementations, fully in libcore, without relying on any complicated libm or runtime support. Most have been stable since 1.0, the most recent one is clamp which is stable since 1.50. So I think we can proceed with const-stabilizing them.

@rust-lang/lang @rust-lang/wg-const-eval this does involve exposing some intrinsics via stable const fn: abs and copysign. Those are both non-arithmetic operations, which means they are defined directly on the bit representation of floats, and could easily be implemented with from_bits/to_bits. Their const-eval interpretation has been used in Miri for years.

traviscross · 2024-11-12T07:11:52Z

@rfcbot fcp merge

rfcbot · 2024-11-12T07:11:54Z

nikomatsakis · 2024-11-13T16:09:52Z

@rfcbot reviewed

rfcbot · 2024-11-13T16:10:09Z

🔔 This is now entering its final comment period, as per the review above. 🔔

rfcbot · 2024-11-23T16:10:36Z

The final comment period, with a disposition to merge, as per the review above, is now complete.

As the automated representative of the governance process, I would like to thank the author for their work and everyone else who contributed.

This will be merged soon.

Rollup merge of rust-lang#133389 - eduardosm:stabilize-const_float_methods, r=RalfJung Stabilize `const_float_methods` Tracking issue: rust-lang#130843 Relnotes: rust-lang#133383 Stabilized const API: ```rust // in `core` impl f32/f64 { pub const fn recip(self) -> Self; pub const fn to_degrees(self) -> Self; pub const fn to_radians(self) -> Self; pub const fn max(self, other: Self) -> Self; pub const fn min(self, other: Self) -> Self; pub const fn clamp(self, min: Self, max: Self) -> Self; pub const fn abs(self) -> Self; pub const fn signum(self) -> Self; pub const fn copysign(self, sign: Self) -> Self; } ``` Closes rust-lang#130843 r? libs-api cc `@RalfJung` -- I think the way const-stability attributes work have change a bit since the last time a wrote a const-stabilization PR, please make sure I got them right.

eduardosm added C-tracking-issue Category: An issue tracking the progress of sth. like the implementation of an RFC T-libs-api Relevant to the library API team, which will review and decide on the PR/issue. labels Sep 25, 2024

eduardosm mentioned this issue Sep 25, 2024

Make some float methods unstable const fn #130568

Merged

rfcbot added proposed-final-comment-period Proposed to merge/close by relevant subteam, see T-<team> label. Will enter FCP once signed off. disposition-merge This issue / PR is in PFCP or FCP with a disposition to merge it. labels Nov 12, 2024

m-ou-se removed the I-libs-api-nominated Nominated for discussion during a libs-api team meeting. label Nov 12, 2024

rfcbot added final-comment-period In the final comment period and will be merged soon unless new substantive objections are raised. and removed proposed-final-comment-period Proposed to merge/close by relevant subteam, see T-<team> label. Will enter FCP once signed off. labels Nov 13, 2024

traviscross removed the I-lang-nominated Nominated for discussion during a lang team meeting. label Nov 13, 2024

tgross35 mentioned this issue Nov 13, 2024

float types: move copysign, abs, signum to libcore #131304

Merged

rfcbot added finished-final-comment-period The final comment period is finished for this PR / Issue. and removed final-comment-period In the final comment period and will be merged soon unless new substantive objections are raised. labels Nov 23, 2024

rfcbot added the to-announce Announce this issue on triage meeting label Nov 23, 2024

rustbot mentioned this issue Nov 23, 2024

Tracking issue for release notes of #130843: Tracking Issue for #![feature(const_float_methods)] #133383

Open

3 tasks

eduardosm mentioned this issue Nov 23, 2024

Stabilize const_float_methods #133389

Merged

bors closed this as completed in 220251e Nov 24, 2024

Provide feedback

Saved searches

Use saved searches to filter your results more quickly

Tracking Issue for `#![feature(const_float_methods)]` #130843

Tracking Issue for `#![feature(const_float_methods)]` #130843

eduardosm commented Sep 25, 2024 •

edited by RalfJung

Loading

RalfJung commented Nov 12, 2024

traviscross commented Nov 12, 2024

rfcbot commented Nov 12, 2024 •

edited

Loading

nikomatsakis commented Nov 13, 2024

rfcbot commented Nov 13, 2024

rfcbot commented Nov 23, 2024

Tracking Issue for #![feature(const_float_methods)] #130843

Tracking Issue for #![feature(const_float_methods)] #130843

Comments

eduardosm commented Sep 25, 2024 • edited by RalfJung Loading

Public API

Steps / History

Unresolved Questions

Footnotes

RalfJung commented Nov 12, 2024

traviscross commented Nov 12, 2024

rfcbot commented Nov 12, 2024 • edited Loading

nikomatsakis commented Nov 13, 2024

rfcbot commented Nov 13, 2024

rfcbot commented Nov 23, 2024

Tracking Issue for `#![feature(const_float_methods)]` #130843

Tracking Issue for `#![feature(const_float_methods)]` #130843

eduardosm commented Sep 25, 2024 •

edited by RalfJung

Loading

rfcbot commented Nov 12, 2024 •

edited

Loading