rust/library/compiler-builtins/libm/src/math, branch stable

Allow a new lint failure in nightly

2025-07-17T08:59:25+00:00

```text warning: function `f32_to_bits` is never used --> libm/src/math/support/float_traits.rs:367:14 | 367 | pub const fn f32_to_bits(x: f32) -> u32 { | ^^^^^^^^^^^ | = note: `#[warn(dead_code)]` on by default warning: function `f64_to_bits` is never used --> libm/src/math/support/float_traits.rs:381:14 | 381 | pub const fn f64_to_bits(x: f64) -> u64 { | ^^^^^^^^^^^ warning: `libm` (lib) generated 2 warnings ``` This is a false positive, see RUST-144060.

libm: Improved integer utilities, implement shifts and bug fixes for i256 and u256

2025-07-01T08:07:48+00:00

`i256` and `u256` - operators now use the same overflow convention as primitives - implement `<<` and `-` (previously just `>>` and `+`) - implement `Ord` correctly (the previous `PartialOrd` was broken) - correct `i256::SIGNED` to `true` The `Int`-trait is extended with `trailing_zeros`, `carrying_add`, and `borrowing_sub`.

fmaximum,fminimum: Fix incorrect result and add tests

2025-06-13T15:36:58+00:00

After adding tests, the current implementation for fminimum fails when provided a negative zero and NaN as inputs: ---- math::fminimum_fmaximum_num::tests::fmaximum_num_spec_tests_f64 stdout ---- thread 'math::fminimum_fmaximum_num::tests::fmaximum_num_spec_tests_f64' panicked at libm/src/math/fminimum_fmaximum_num.rs:240:13: fmaximum_num(-0x0p+0, NaN) l: NaN (0x7ff8000000000000) r: -0.0 (0x8000000000000000) ---- math::fminimum_fmaximum_num::tests::fmaximum_num_spec_tests_f32 stdout ---- thread 'math::fminimum_fmaximum_num::tests::fmaximum_num_spec_tests_f32' panicked at libm/src/math/fminimum_fmaximum_num.rs:240:13: fmaximum_num(-0x0p+0, NaN) l: NaN (0x7fc00000) r: -0.0 (0x80000000) Add more thorough spec tests for these functions and correct the implementations. Canonicalization is also moved to a trait method to centralize documentation about what it does and doesn't do.

libm-test: Fix unintentional skips in `binop_common`

2025-06-02T22:47:15+00:00

`binop_common` emits a `SKIP` that is intended to apply only to `copysign`, but is instead applying to all binary operators. Correct the general case but leave the currently-failing `maximum_num` tests as a FIXME, to be resolved separately in [1]. Also simplify skip logic and NaN checking, and add a few more `copysign` checks. [1]: https://github.com/rust-lang/compiler-builtins/pull/939

cleanup: Use `x.biteq(y)` rather than `x.to_bits() == y.to_bits()`

2025-06-02T16:10:49+00:00

Fix new `dead_code` warnings from recent nightlies

2025-06-01T19:54:30+00:00

Reuse `libm`'s `Caat` and `CastFrom` in `compiler-builtins`

2025-05-29T03:56:08+00:00

cleanup: Reuse `MinInt` and `Int` from `libm` in `compiler-builtins`

2025-05-29T03:04:59+00:00

Since the two crates are now in the same repo, it is easier to share code. Begin some deduplication with the integer traits.

aarch64: Add a note saying why we use `frintx` rather than `frintn`

2025-05-28T21:10:28+00:00

Update `CmpResult` to use a pointer-sized return type

2025-05-28T06:58:42+00:00

As seen at [1], LLVM uses `long long` on LLP64 (to get a 64-bit integer matching pointer size) and `long` on everything else, with exceptions for AArch64 and AVR. Our current logic always uses an `i32`. This happens to work because LLVM uses 32-bit instructions to check the output on x86-64, but the GCC checks the full 64-bit register so garbage in the upper half leads to incorrect results. Update our return type to be `isize`, with exceptions for AArch64 and AVR. Fixes: https://github.com/rust-lang/compiler-builtins/issues/919 [1]: https://github.com/llvm/llvm-project/blob/0cf3c437c18ed27d9663d87804a9a15ff6874af2/compiler-rt/lib/builtins/fp_compare_impl.inc#L11-L27