…-nondet, r=RalfJung

Enable Non-determinism of float operations in Miri and change std tests

Links to [rust-lang#4208](rust-lang/miri#4208) and [rust-lang#3555](rust-lang/miri#3555) in Miri.

Non-determinism of floating point operations was disabled in rust-lang#137594 because it breaks the tests and doc-tests in core/coretests and std. This PR enables some of them.

This pr includes the following changes:

- Enables the float non-determinism but with a lower relative error of 4ULP instead of 16ULP
- These operations now have a fixed output based on the C23 standard, except the pow operations, this is tracked in [rust-lang#4286](rust-lang/miri#4286 (comment))
- Changes tests that made incorrect assumptions about the operations, not to make that assumption anymore (from `assert_eq!` to `assert_approx_eq!`.
- Changed the doctests of the stdlib of these operations to compare against fixed constants instead of `f*::EPSILON`, which now succeed with Miri and `-Zmiri-many-seeds`
- Added a constant `APPROX_DELTA` in `std/tests/floats/f32.rs` which is used for approximation tests, but with a different value when run in Miri. This is to make these tests succeed.
- Added tests in the float tests of Miri to test the C23 behaviour.

Fixes rust-lang/miri#4208

…-nondet, r=RalfJung

Enable Non-determinism of float operations in Miri and change std tests

Links to [rust-lang#4208](rust-lang/miri#4208) and [rust-lang#3555](rust-lang/miri#3555) in Miri.

Non-determinism of floating point operations was disabled in rust-lang#137594 because it breaks the tests and doc-tests in core/coretests and std. This PR enables some of them.

This pr includes the following changes:

- Enables the float non-determinism but with a lower relative error of 4ULP instead of 16ULP
- These operations now have a fixed output based on the C23 standard, except the pow operations, this is tracked in [rust-lang#4286](rust-lang/miri#4286 (comment))
- Changes tests that made incorrect assumptions about the operations, not to make that assumption anymore (from `assert_eq!` to `assert_approx_eq!`.
- Changed the doctests of the stdlib of these operations to compare against fixed constants instead of `f*::EPSILON`, which now succeed with Miri and `-Zmiri-many-seeds`
- Added a constant `APPROX_DELTA` in `std/tests/floats/f32.rs` which is used for approximation tests, but with a different value when run in Miri. This is to make these tests succeed.
- Added tests in the float tests of Miri to test the C23 behaviour.

Fixes rust-lang/miri#4208

…RalfJung

Enable Non-determinism of float operations in Miri and change std tests

Links to [#4208](rust-lang/miri#4208) and [#3555](rust-lang/miri#3555) in Miri.

Non-determinism of floating point operations was disabled in #137594 because it breaks the tests and doc-tests in core/coretests and std. This PR enables some of them.

This pr includes the following changes:

- Enables the float non-determinism but with a lower relative error of 4ULP instead of 16ULP
- These operations now have a fixed output based on the C23 standard, except the pow operations, this is tracked in [#4286](rust-lang/miri#4286 (comment))
- Changes tests that made incorrect assumptions about the operations, not to make that assumption anymore (from `assert_eq!` to `assert_approx_eq!`.
- Changed the doctests of the stdlib of these operations to compare against fixed constants instead of `f*::EPSILON`, which now succeed with Miri and `-Zmiri-many-seeds`
- Added a constant `APPROX_DELTA` in `std/tests/floats/f32.rs` which is used for approximation tests, but with a different value when run in Miri. This is to make these tests succeed.
- Added tests in the float tests of Miri to test the C23 behaviour.

Fixes rust-lang/miri#4208

…RalfJung

Enable Non-determinism of float operations in Miri and change std tests

Links to [#4208](rust-lang/miri#4208) and [#3555](rust-lang/miri#3555) in Miri.

Non-determinism of floating point operations was disabled in #137594 because it breaks the tests and doc-tests in core/coretests and std. This PR enables some of them.

This pr includes the following changes:

- Enables the float non-determinism but with a lower relative error of 4ULP instead of 16ULP
- These operations now have a fixed output based on the C23 standard, except the pow operations, this is tracked in [#4286](rust-lang/miri#4286 (comment))
- Changes tests that made incorrect assumptions about the operations, not to make that assumption anymore (from `assert_eq!` to `assert_approx_eq!`.
- Changed the doctests of the stdlib of these operations to compare against fixed constants instead of `f*::EPSILON`, which now succeed with Miri and `-Zmiri-many-seeds`
- Added a constant `APPROX_DELTA` in `std/tests/floats/f32.rs` which is used for approximation tests, but with a different value when run in Miri. This is to make these tests succeed.
- Added tests in the float tests of Miri to test the C23 behaviour.

Fixes rust-lang/miri#4208

…<try>

Enable Non-determinism of float operations in Miri and change std tests

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Links to [#4208](rust-lang/miri#4208) and [#3555](rust-lang/miri#3555) in Miri.

Non-determinism of floating point operations was disabled in #137594 because it breaks the tests and doc-tests in core/coretests and std. This PR enables some of them.

This pr includes the following changes:

- Enables the float non-determinism but with a lower relative error of 4ULP instead of 16ULP
- These operations now have a fixed output based on the C23 standard, except the pow operations, this is tracked in [#4286](rust-lang/miri#4286 (comment))
- Changes tests that made incorrect assumptions about the operations, not to make that assumption anymore (from `assert_eq!` to `assert_approx_eq!`.
- Changed the doctests of the stdlib of these operations to compare against fixed constants instead of `f*::EPSILON`, which now succeed with Miri and `-Zmiri-many-seeds`
- Added a constant `APPROX_DELTA` in `std/tests/floats/f32.rs` which is used for approximation tests, but with a different value when run in Miri. This is to make these tests succeed.
- Added tests in the float tests of Miri to test the C23 behaviour.

Fixes rust-lang/miri#4208
try-job: aarch64-apple

…<try>

Enable Non-determinism of float operations in Miri and change std tests

<!-- homu-ignore:start -->
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please link to the relevant tracking issue here. If you don't know of a related
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Links to [#4208](rust-lang/miri#4208) and [#3555](rust-lang/miri#3555) in Miri.

Non-determinism of floating point operations was disabled in #137594 because it breaks the tests and doc-tests in core/coretests and std. This PR enables some of them.

This pr includes the following changes:

- Enables the float non-determinism but with a lower relative error of 4ULP instead of 16ULP
- These operations now have a fixed output based on the C23 standard, except the pow operations, this is tracked in [#4286](rust-lang/miri#4286 (comment))
- Changes tests that made incorrect assumptions about the operations, not to make that assumption anymore (from `assert_eq!` to `assert_approx_eq!`.
- Changed the doctests of the stdlib of these operations to compare against fixed constants instead of `f*::EPSILON`, which now succeed with Miri and `-Zmiri-many-seeds`
- Added a constant `APPROX_DELTA` in `std/tests/floats/f32.rs` which is used for approximation tests, but with a different value when run in Miri. This is to make these tests succeed.
- Added tests in the float tests of Miri to test the C23 behaviour.

Fixes rust-lang/miri#4208
try-job: aarch64-apple

…RalfJung

Enable Non-determinism of float operations in Miri and change std tests

Links to [#4208](rust-lang/miri#4208) and [#3555](rust-lang/miri#3555) in Miri.

Non-determinism of floating point operations was disabled in #137594 because it breaks the tests and doc-tests in core/coretests and std. This PR enables some of them.

This pr includes the following changes:

- Enables the float non-determinism but with a lower relative error of 4ULP instead of 16ULP
- These operations now have a fixed output based on the C23 standard, except the pow operations, this is tracked in [#4286](rust-lang/miri#4286 (comment))
- Changes tests that made incorrect assumptions about the operations, not to make that assumption anymore (from `assert_eq!` to `assert_approx_eq!`.
- Changed the doctests of the stdlib of these operations to compare against fixed constants instead of `f*::EPSILON`, which now succeed with Miri and `-Zmiri-many-seeds`
- Added a constant `APPROX_DELTA` in `std/tests/floats/f32.rs` which is used for approximation tests, but with a different value when run in Miri. This is to make these tests succeed.
- Added tests in the float tests of Miri to test the C23 behaviour.

Fixes rust-lang/miri#4208

…ondet, r=RalfJung

Enable Non-determinism of float operations in Miri and change std tests

Links to [rust-lang#4208](rust-lang/miri#4208) and [rust-lang#3555](rust-lang/miri#3555) in Miri.

Non-determinism of floating point operations was disabled in rust-lang#137594 because it breaks the tests and doc-tests in core/coretests and std. This PR enables some of them.

This pr includes the following changes:

- Enables the float non-determinism but with a lower relative error of 4ULP instead of 16ULP
- These operations now have a fixed output based on the C23 standard, except the pow operations, this is tracked in [rust-lang#4286](rust-lang/miri#4286 (comment))
- Changes tests that made incorrect assumptions about the operations, not to make that assumption anymore (from `assert_eq!` to `assert_approx_eq!`.
- Changed the doctests of the stdlib of these operations to compare against fixed constants instead of `f*::EPSILON`, which now succeed with Miri and `-Zmiri-many-seeds`
- Added a constant `APPROX_DELTA` in `std/tests/floats/f32.rs` which is used for approximation tests, but with a different value when run in Miri. This is to make these tests succeed.
- Added tests in the float tests of Miri to test the C23 behaviour.

Fixes rust-lang/miri#4208

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

<!-- homu-ignore:start -->
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please link to the relevant tracking issue here. If you don't know of a related
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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

…-pow, r=RalfJung

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

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

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`