f*::NAN: guarantee that this is a quiet NaN #139483
Merged
Conversation
This file contains hidden or bidirectional Unicode text that may be interpreted or compiled differently than what appears below. To review, open the file in an editor that reveals hidden Unicode characters.
Learn more about bidirectional Unicode characters
rustbot
added
S-waiting-on-review
RalfJung
added
the
I-libs-api-nominated
m-ou-se
added
T-libs-api
|
@rfcbot merge |
|
Team member @m-ou-se has proposed to merge this. The next step is review by the rest of the tagged team members: No concerns currently listed. Once a majority of reviewers approve (and at most 2 approvals are outstanding), this will enter its final comment period. If you spot a major issue that hasn't been raised at any point in this process, please speak up! See this document for info about what commands tagged team members can give me. |
rfcbot
added
proposed-final-comment-period
tbu-
reviewed
Apr 7, 2025
|
The Miri subtree was changed cc @rust-lang/miri |
rfcbot
added
final-comment-period
|
🔔 This is now entering its final comment period, as per the review above. 🔔 |
|
Is it worth considering the alternative of making no guarantees about |
|
I think adding a |
rfcbot
added
finished-final-comment-period
|
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. |
tgross35
approved these changes
Apr 17, 2025
|
r? tgross35 |
bors
added
the
S-waiting-on-bors
bors
added a commit
to rust-lang-ci/rust
that referenced
this pull request
Apr 17, 2025
…iaskrgr Rollup of 8 pull requests Successful merges: - rust-lang#139351 (Autodiff batching2) - rust-lang#139483 (f*::NAN: guarantee that this is a quiet NaN) - rust-lang#139498 (Ignore zero-sized types in wasm future-compat warning) - rust-lang#139967 (Introduce and use specialized `//@ ignore-auxiliary` for test support files instead of using `//@ ignore-test`) - rust-lang#139969 (update libc) - rust-lang#139971 (Make C string merging test work on MIPS) - rust-lang#139974 (Change `InterpCx::instantiate*` function visibility to pub) - rust-lang#139977 (Fix drop handling in `hint::select_unpredictable`) r? `@ghost` `@rustbot` modify labels: rollup
rust-timer
added a commit
to rust-lang-ci/rust
that referenced
this pull request
Apr 18, 2025
Rollup merge of rust-lang#139483 - RalfJung:nan, r=tgross35 f*::NAN: guarantee that this is a quiet NaN I think we should guarantee that this is a quiet NaN. This then implies that programs not using `f*::from_bits` (or unsafe type conversions) are guaranteed to only work with quiet NaNs. It would be awkward if people start to write `0.0 / 0.0` instead of using the constant just because they want to get a guaranteed-quiet NaN. This is a `@rust-lang/libs-api` change. The definition of this constant currently is `0.0 / 0.0`, which is already guaranteed to be a quiet NaN. So all this does is forward that guarantee to our users.
|
I didn't think of this until just now but we should add a test ensuring the top mantissa bit is set |
github-actions bot
pushed a commit
to model-checking/verify-rust-std
that referenced
this pull request
Apr 19, 2025
f*::NAN: guarantee that this is a quiet NaN I think we should guarantee that this is a quiet NaN. This then implies that programs not using `f*::from_bits` (or unsafe type conversions) are guaranteed to only work with quiet NaNs. It would be awkward if people start to write `0.0 / 0.0` instead of using the constant just because they want to get a guaranteed-quiet NaN. This is a `@rust-lang/libs-api` change. The definition of this constant currently is `0.0 / 0.0`, which is already guaranteed to be a quiet NaN. So all this does is forward that guarantee to our users.
|
@tgross35 what's the best way to get the top mantissa bit for our various float types? |
|
I think |
ChrisDenton
added a commit
to ChrisDenton/rust
that referenced
this pull request
Apr 22, 2025
test_nan: ensure the NAN contant is quiet Follow-up to rust-lang#139483 r? `@tgross35`
ChrisDenton
added a commit
to ChrisDenton/rust
that referenced
this pull request
Apr 22, 2025
test_nan: ensure the NAN contant is quiet Follow-up to rust-lang#139483 r? ``@tgross35``
rust-timer
added a commit
to rust-lang-ci/rust
that referenced
this pull request
Apr 23, 2025
Rollup merge of rust-lang#140149 - RalfJung:test_nan, r=tgross35 test_nan: ensure the NAN contant is quiet Follow-up to rust-lang#139483 r? ``@tgross35``
github-actions bot
pushed a commit
to rust-lang/miri
that referenced
this pull request
Apr 23, 2025
test_nan: ensure the NAN contant is quiet Follow-up to rust-lang/rust#139483 r? ``@tgross35``
Sign up for free
to join this conversation on GitHub.
Already have an account?
Sign in to comment
Add this suggestion to a batch that can be applied as a single commit.
This suggestion is invalid because no changes were made to the code.
Suggestions cannot be applied while the pull request is closed.
Suggestions cannot be applied while viewing a subset of changes.
Only one suggestion per line can be applied in a batch.
Add this suggestion to a batch that can be applied as a single commit.
Applying suggestions on deleted lines is not supported.
You must change the existing code in this line in order to create a valid suggestion.
Outdated suggestions cannot be applied.
This suggestion has been applied or marked resolved.
Suggestions cannot be applied from pending reviews.
Suggestions cannot be applied on multi-line comments.
Suggestions cannot be applied while the pull request is queued to merge.
Suggestion cannot be applied right now. Please check back later.
I think we should guarantee that this is a quiet NaN. This then implies that programs not using
f*::from_bits(or unsafe type conversions) are guaranteed to only work with quiet NaNs. It would be awkward if people start to write0.0 / 0.0instead of using the constant just because they want to get a guaranteed-quiet NaN.This is a @rust-lang/libs-api change. The definition of this constant currently is
0.0 / 0.0, which is already guaranteed to be a quiet NaN. So all this does is forward that guarantee to our users.