x86 soft-float feature: mark it as forbidden rather than unstable by RalfJung · Pull Request #151317 · rust-lang/rust

RalfJung · 2026-01-18T16:20:19Z

I am not sure why I made it "unstable" in f755f4c; I think at the time "forbidden" did not work for some reason.

Making it "forbidden" instead has no significant effect on -Ctarget-feature use, it just changes the warning. It does have the effect that one cannot query this using cfg(target_feature) on nightly any more, but that seems fine to me. It only ever worked as an accidental side-effect of f755f4c anyway.

r? @workingjubilee

rustbot · 2026-01-18T16:20:23Z

workingjubilee is currently at their maximum review capacity.
They may take a while to respond.

workingjubilee · 2026-01-20T21:46:22Z

yesteryear's Ralf said:

Making this "forbidden" just leads to duplicate warnings so there's little point in doing that.

This makes riscv's forced-atomics the only remaining "forbidden" feature.

RalfJung · 2026-01-20T21:51:28Z

🤔

Hm, there is also the cfg part that I apparently missed back then.

workingjubilee · 2026-01-20T21:51:58Z

It does have the effect that one cannot query this using cfg(target_feature) on nightly any more, but that seems fine to me. It only ever worked as an accidental side-effect of f755f4c anyway.

I don't mind breaking this, but that's a subtle change that nothing currently detects. Could we have a test?

workingjubilee · 2026-01-20T21:59:18Z

I'm getting high "yeah this is roughly what we want" vibes from the way Jubilee was talking in that PR, so I think I definitely evaluated the diff, and was thinking about target.rustc_abi, but I probably wasn't deeply interrogating it to "beyond this, what might we also want?" Even if I did, I probably would have only filed followup issues.

So Ralf Junger could have just been subtly wrong (or right in a way that quickly changed) and Jubilee Younger could have just been kinda vibing on that point since it didn't seem terribly important. As I noted previously, it's affecting nightly-only stuff, so everyone bought the ticket on the ride they're going to get taken on if they depended on this detail, especially given it was previously Forbidden.

workingjubilee · 2026-01-20T22:03:27Z

Ohhh, maybe the "duplicate warnings" was for both setting "+soft-float" at all and mismatch with rustc_abi? That was definitely a thing that was possible, but was effectively a transient state (people should have fixed the mismatch by now) and I think we got a bit stricter on what we accept in the target.json when we moved to a Serde-based deserialization. So now I think we can assume people have both configured or not-configured as appropriate, and so just shrug and be double-noisy.

RalfJung · 2026-01-21T12:39:09Z

Fair point, I will add a test.

Ohhh, maybe the "duplicate warnings" was for both setting "+soft-float" at all and mismatch with rustc_abi? That was definitely a thing that was possible, but was effectively a transient state (people should have fixed the mismatch by now) and I think we got a bit stricter on what we accept in the target.json when we moved to a Serde-based deserialization. So now I think we can assume people have both configured or not-configured as appropriate, and so just shrug and be double-noisy.

"Forbidden" still allows the feature to be set in target specs, so I don't think it was this.

workingjubilee · 2026-01-24T22:09:46Z

cool. Let's hope we at least figure out what we were thinking about when we wind up revisiting this for some reason in 2027. :^)

@bors r+ rollup

rust-bors · 2026-01-24T22:09:49Z

📌 Commit fdc7cfd has been approved by workingjubilee

It is now in the queue for this repository.

@workingjubilee

…jubilee x86 soft-float feature: mark it as forbidden rather than unstable I am not sure why I made it "unstable" in rust-lang@f755f4c; I think at the time "forbidden" did not work for some reason. Making it "forbidden" instead has no significant effect on `-Ctarget-feature` use, it just changes the warning. It *does* have the effect that one cannot query this using `cfg(target_feature)` on nightly any more, but that seems fine to me. It only ever worked as an accidental side-effect of f755f4c anyway. r? @workingjubilee

…uwer Rollup of 11 pull requests Successful merges: - #145393 (Add codegen test for removing trailing zeroes from `NonZero`) - #148764 (ptr_aligment_type: add more APIs) - #149869 (std: avoid tearing `dbg!` prints) - #150065 (add CSE optimization tests for iterating over slice) - #150842 (Fix(lib/win/thread): Ensure `Sleep`'s usage passes over the requested duration under Win7) - #151505 (Various refactors to the proc_macro bridge) - #151560 (relnotes: fix 1.93's `as_mut_array` methods) - #151611 (Improve is_ascii performance on x86_64 with explicit SSE2 intrinsics) - #151317 (x86 soft-float feature: mark it as forbidden rather than unstable) - #151577 (Rename `DepKindStruct` to `DepKindVTable`) - #151620 (Fix 'the the' typo in library/core/src/array/iter.rs)

Rollup of 10 pull requests Successful merges: - #145393 (Add codegen test for removing trailing zeroes from `NonZero`) - #148764 (ptr_aligment_type: add more APIs) - #149869 (std: avoid tearing `dbg!` prints) - #150065 (add CSE optimization tests for iterating over slice) - #150842 (Fix(lib/win/thread): Ensure `Sleep`'s usage passes over the requested duration under Win7) - #151505 (Various refactors to the proc_macro bridge) - #151560 (relnotes: fix 1.93's `as_mut_array` methods) - #151317 (x86 soft-float feature: mark it as forbidden rather than unstable) - #151577 (Rename `DepKindStruct` to `DepKindVTable`) - #151620 (Fix 'the the' typo in library/core/src/array/iter.rs)

@workingjubilee

Rollup merge of #151317 - RalfJung:x86-soft-float, r=workingjubilee x86 soft-float feature: mark it as forbidden rather than unstable I am not sure why I made it "unstable" in f755f4c; I think at the time "forbidden" did not work for some reason. Making it "forbidden" instead has no significant effect on `-Ctarget-feature` use, it just changes the warning. It *does* have the effect that one cannot query this using `cfg(target_feature)` on nightly any more, but that seems fine to me. It only ever worked as an accidental side-effect of f755f4c anyway. r? @workingjubilee

Rollup of 10 pull requests Successful merges: - rust-lang/rust#145393 (Add codegen test for removing trailing zeroes from `NonZero`) - rust-lang/rust#148764 (ptr_aligment_type: add more APIs) - rust-lang/rust#149869 (std: avoid tearing `dbg!` prints) - rust-lang/rust#150065 (add CSE optimization tests for iterating over slice) - rust-lang/rust#150842 (Fix(lib/win/thread): Ensure `Sleep`'s usage passes over the requested duration under Win7) - rust-lang/rust#151505 (Various refactors to the proc_macro bridge) - rust-lang/rust#151560 (relnotes: fix 1.93's `as_mut_array` methods) - rust-lang/rust#151317 (x86 soft-float feature: mark it as forbidden rather than unstable) - rust-lang/rust#151577 (Rename `DepKindStruct` to `DepKindVTable`) - rust-lang/rust#151620 (Fix 'the the' typo in library/core/src/array/iter.rs)

rustbot assigned workingjubilee Jan 18, 2026

rustbot added S-waiting-on-review Status: Awaiting review from the assignee but also interested parties. T-compiler Relevant to the compiler team, which will review and decide on the PR/issue. labels Jan 18, 2026

RalfJung force-pushed the x86-soft-float branch from 4fd7c23 to c7f6b3f Compare January 21, 2026 12:47

This comment has been minimized.

Sign in to view

x86 soft-float feature: mark it as forbidden rather than unstable

fdc7cfd

RalfJung force-pushed the x86-soft-float branch from c7f6b3f to fdc7cfd Compare January 21, 2026 14:04

rust-bors bot added S-waiting-on-bors Status: Waiting on bors to run and complete tests. Bors will change the label on completion. and removed S-waiting-on-review Status: Awaiting review from the assignee but also interested parties. labels Jan 24, 2026

JonathanBrouwer mentioned this pull request Jan 25, 2026

Rollup of 11 pull requests #151627

Closed

matthiaskrgr mentioned this pull request Jan 25, 2026

Rollup of 10 pull requests #151634

Merged

rust-bors bot merged commit 17ba7f2 into rust-lang:main Jan 25, 2026
11 checks passed

rustbot added this to the 1.95.0 milestone Jan 25, 2026

RalfJung deleted the x86-soft-float branch January 28, 2026 16:05

Provide feedback

Saved searches

Use saved searches to filter your results more quickly

Uh oh!

x86 soft-float feature: mark it as forbidden rather than unstable#151317

x86 soft-float feature: mark it as forbidden rather than unstable#151317
rust-bors[bot] merged 1 commit intorust-lang:mainfrom
RalfJung:x86-soft-float

RalfJung commented Jan 18, 2026

Uh oh!

rustbot commented Jan 18, 2026

Uh oh!

workingjubilee commented Jan 20, 2026

Uh oh!

RalfJung commented Jan 20, 2026

Uh oh!

workingjubilee commented Jan 20, 2026

Uh oh!

workingjubilee commented Jan 20, 2026

Uh oh!

workingjubilee commented Jan 20, 2026 •

edited

Loading

Uh oh!

RalfJung commented Jan 21, 2026

Uh oh!

This comment has been minimized.

workingjubilee commented Jan 24, 2026

Uh oh!

rust-bors bot commented Jan 24, 2026

Uh oh!

Uh oh!

Reviewers

Assignees

Labels

Projects

Milestone

Development

Uh oh!

4 participants

Uh oh!

Conversation

RalfJung commented Jan 18, 2026

Uh oh!

rustbot commented Jan 18, 2026

Uh oh!

workingjubilee commented Jan 20, 2026

Uh oh!

RalfJung commented Jan 20, 2026

Uh oh!

workingjubilee commented Jan 20, 2026

Uh oh!

workingjubilee commented Jan 20, 2026

Uh oh!

workingjubilee commented Jan 20, 2026 • edited Loading Uh oh! There was an error while loading. Please reload this page.

Uh oh!

Uh oh!

RalfJung commented Jan 21, 2026

Uh oh!

This comment has been minimized.

workingjubilee commented Jan 24, 2026

Uh oh!

rust-bors bot commented Jan 24, 2026

Uh oh!

Uh oh!

Reviewers

Assignees

Labels

Projects

Milestone

Development

Uh oh!

4 participants

workingjubilee commented Jan 20, 2026 •

edited

Loading