Miri: handling of SNaN inputs in `f*::pow` operations by LorrensP-2158466 · Pull Request #142514

Miri: handling of SNaN inputs in `f*::pow` operations by LorrensP-2158466 · Pull Request #142514 · rust-lang/rust

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Miri: handling of SNaN inputs in `f*::pow` operations

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fixes [miri/#4286](rust-lang/miri#4286) and related to #138062 and [miri/#4208](rust-lang/miri#4208 (comment)).

For the following cases of the powf or powi operations, Miri returns either `1.0` or an arbitrary `NaN`:
- `powf(SNaN, 0.0)`
- `powf(1.0, SNaN)`
- `powi(SNaN, 0)`

Also added a macro in `miri/tests/pass/float.rs` which conveniently checks if both are indeed returned from such an operation.

Made these changes in the rust repo so I could test against stdlib, since these were impacted some time ago and were fixed in #138062. Tested with:
```fish
env MIRIFLAGS=-Zmiri-many-seeds ./x miri --no-fail-fast std core coretests -- f32 f64
```
This was successful. This does take a while, so I recommend using `--no-doc` and separate use of `f32` or `f64`

The pr is somewhat split up into 3 main commits, which implement the cases described above. The first commit also introduces the macro, and the last commit is just a global refactor of some things.

r? `@RalfJung`
try-job: x86_64-gnu-aux

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Jun 29, 2025

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plus various minor tweaks

bors added a commit that referenced this pull request

Jun 30, 2025

Rollup of 14 pull requests

Successful merges:

 - #142429 (`tests/ui`: A New Order [13/N])
 - #142514 (Miri: handling of SNaN inputs in `f*::pow` operations)
 - #143066 (Use let chains in the new solver)
 - #143090 (Workaround for memory unsafety in third party DLLs)
 - #143118 (`tests/ui`: A New Order [15/N])
 - #143159 (Do not freshen `ReError`)
 - #143168 (`tests/ui`: A New Order [16/N])
 - #143176 (fix typos and improve clarity in documentation)
 - #143187 (Add my work email to mailmap)
 - #143190 (Use the `new` method for `BasicBlockData` and `Statement`)
 - #143195 (`tests/ui`: A New Order [17/N])
 - #143196 (Port #[link_section] to the new attribute parsing infrastructure)
 - #143199 (Re-disable `tests/run-make/short-ice` on Windows MSVC again)
 - #143219 (Show auto trait and blanket impls for `!`)

r? `@ghost`
`@rustbot` modify labels: rollup

rust-timer added a commit that referenced this pull request

Jun 30, 2025

Rollup merge of #142514 - LorrensP-2158466:miri-float-nondet-pow, r=RalfJung

Miri: handling of SNaN inputs in `f*::pow` operations

fixes [miri/#4286](rust-lang/miri#4286) and related to #138062 and [miri/#4208](rust-lang/miri#4208 (comment)).

For the following cases of the powf or powi operations, Miri returns either `1.0` or an arbitrary `NaN`:
- `powf(SNaN, 0.0)`
- `powf(1.0, SNaN)`
- `powi(SNaN, 0)`

Also added a macro in `miri/tests/pass/float.rs` which conveniently checks if both are indeed returned from such an operation.

Made these changes in the rust repo so I could test against stdlib, since these were impacted some time ago and were fixed in #138062. Tested with:
```fish
env MIRIFLAGS=-Zmiri-many-seeds ./x miri --no-fail-fast std core coretests -- f32 f64
```
This was successful. This does take a while, so I recommend using `--no-doc` and separate use of `f32` or `f64`

The pr is somewhat split up into 3 main commits, which implement the cases described above. The first commit also introduces the macro, and the last commit is just a global refactor of some things.

r? `@RalfJung`

github-actions bot pushed a commit to rust-lang/miri that referenced this pull request

Jul 1, 2025

Kobzol pushed a commit to Kobzol/stdarch that referenced this pull request

Jul 2, 2025

github-actions bot pushed a commit to rust-lang/rustc-dev-guide that referenced this pull request

Jul 3, 2025

github-actions bot pushed a commit to model-checking/verify-rust-std that referenced this pull request

Jul 4, 2025

GuillaumeGomez added a commit to GuillaumeGomez/rust that referenced this pull request

Jul 20, 2025

…-foreign-items, r=RalfJung

Miri: non-deterministic floating point operations in `foreign_items`

Part of [rust-lang/miri/rust-lang#3555](rust-lang/miri#3555 (comment)), this pr does the `foreign_items` work.

Some things have changed since rust-lang#138062 and rust-lang#142514. I moved the "helpers" used for creating fixed outputs and clamping operations to their defined ranges to `helpers.rs`. These are now also extended to handle the floating-point operations in `foreign_items`. Tests in `miri/tests/float.rs` were changed/added.

Failing tests in `std` were extracted, run under miri with `-Zmiri-many-seeds=0..1000` and changed accordingly. Double checked with `-Zmiri-many-seeds`.

I noticed that the C standard doesn't specify the output ranges for all of its mathematical operations; it just specifies them as:
```
Returns
The sinh functions return sinh x.
```
So I used [Wolfram|Alpha](https://www.wolframalpha.com/).

GuillaumeGomez added a commit to GuillaumeGomez/rust that referenced this pull request

Jul 20, 2025

…-foreign-items, r=RalfJung

Miri: non-deterministic floating point operations in `foreign_items`

Part of [rust-lang/miri/rust-lang#3555](rust-lang/miri#3555 (comment)), this pr does the `foreign_items` work.

Some things have changed since rust-lang#138062 and rust-lang#142514. I moved the "helpers" used for creating fixed outputs and clamping operations to their defined ranges to `helpers.rs`. These are now also extended to handle the floating-point operations in `foreign_items`. Tests in `miri/tests/float.rs` were changed/added.

Failing tests in `std` were extracted, run under miri with `-Zmiri-many-seeds=0..1000` and changed accordingly. Double checked with `-Zmiri-many-seeds`.

I noticed that the C standard doesn't specify the output ranges for all of its mathematical operations; it just specifies them as:
```
Returns
The sinh functions return sinh x.
```
So I used [Wolfram|Alpha](https://www.wolframalpha.com/).

matthiaskrgr added a commit to matthiaskrgr/rust that referenced this pull request

Jul 22, 2025

…-foreign-items, r=RalfJung

Miri: non-deterministic floating point operations in `foreign_items`

Part of [rust-lang/miri/rust-lang#3555](rust-lang/miri#3555 (comment)), this pr does the `foreign_items` work.

Some things have changed since rust-lang#138062 and rust-lang#142514. I moved the "helpers" used for creating fixed outputs and clamping operations to their defined ranges to `math.rs`. These are now also extended to handle the floating-point operations in `foreign_items`. Tests in `miri/tests/float.rs` were changed/added.

Failing tests in `std` were extracted, run under miri with `-Zmiri-many-seeds=0..1000` and changed accordingly. Double checked with `-Zmiri-many-seeds`.

I noticed that the C standard doesn't specify the output ranges for all of its mathematical operations; it just specifies them as:
```
Returns
The sinh functions return sinh x.
```
So I used [Wolfram|Alpha](https://www.wolframalpha.com/).

matthiaskrgr added a commit to matthiaskrgr/rust that referenced this pull request

Jul 22, 2025

…-foreign-items, r=RalfJung

Miri: non-deterministic floating point operations in `foreign_items`

Part of [rust-lang/miri/rust-lang#3555](rust-lang/miri#3555 (comment)), this pr does the `foreign_items` work.

Some things have changed since rust-lang#138062 and rust-lang#142514. I moved the "helpers" used for creating fixed outputs and clamping operations to their defined ranges to `math.rs`. These are now also extended to handle the floating-point operations in `foreign_items`. Tests in `miri/tests/float.rs` were changed/added.

Failing tests in `std` were extracted, run under miri with `-Zmiri-many-seeds=0..1000` and changed accordingly. Double checked with `-Zmiri-many-seeds`.

I noticed that the C standard doesn't specify the output ranges for all of its mathematical operations; it just specifies them as:
```
Returns
The sinh functions return sinh x.
```
So I used [Wolfram|Alpha](https://www.wolframalpha.com/).