diff --git a/library/compiler-builtins/libm/crates/libm-bench/benches/bench.rs b/library/compiler-builtins/libm/crates/libm-bench/benches/bench.rs index b6d8741531f3..ca999b90f27c 100644 --- a/library/compiler-builtins/libm/crates/libm-bench/benches/bench.rs +++ b/library/compiler-builtins/libm/crates/libm-bench/benches/bench.rs @@ -107,7 +107,8 @@ macro_rules! bessel { unary!( acos, acosh, asin, atan, cbrt, ceil, cos, cosh, erf, exp, exp2, exp10, expm1, fabs, floor, j0, - j1, lgamma, log, log1p, log2, log10, round, sin, sinh, sqrt, tan, tanh, tgamma, trunc, y0, y1 + j1, lgamma, log, log1p, log2, log10, rint, round, sin, sinh, sqrt, tan, tanh, tgamma, trunc, + y0, y1 ); binary!(atan2, copysign, fdim, fmax, fmin, fmod, hypot, pow); trinary!(fma); diff --git a/library/compiler-builtins/libm/src/math/mod.rs b/library/compiler-builtins/libm/src/math/mod.rs index 81bfc53ed854..05ebb708c9c5 100644 --- a/library/compiler-builtins/libm/src/math/mod.rs +++ b/library/compiler-builtins/libm/src/math/mod.rs @@ -170,6 +170,8 @@ mod remainder; mod remainderf; mod remquo; mod remquof; +mod rint; +mod rintf; mod round; mod roundf; mod scalbn; @@ -284,6 +286,8 @@ pub use self::remainder::remainder; pub use self::remainderf::remainderf; pub use self::remquo::remquo; pub use self::remquof::remquof; +pub use self::rint::rint; +pub use self::rintf::rintf; pub use self::round::round; pub use self::roundf::roundf; pub use self::scalbn::scalbn; diff --git a/library/compiler-builtins/libm/src/math/rint.rs b/library/compiler-builtins/libm/src/math/rint.rs new file mode 100644 index 000000000000..0c6025c1f73d --- /dev/null +++ b/library/compiler-builtins/libm/src/math/rint.rs @@ -0,0 +1,48 @@ +#[cfg_attr(all(test, assert_no_panic), no_panic::no_panic)] +pub fn rint(x: f64) -> f64 { + let one_over_e = 1.0 / f64::EPSILON; + let as_u64: u64 = x.to_bits(); + let exponent: u64 = as_u64 >> 52 & 0x7ff; + let is_positive = (as_u64 >> 63) == 0; + if exponent >= 0x3ff + 52 { + x + } else { + let ans = if is_positive { + x + one_over_e - one_over_e + } else { + x - one_over_e + one_over_e + }; + + if ans == 0.0 { + if is_positive { + 0.0 + } else { + -0.0 + } + } else { + ans + } + } +} + +// PowerPC tests are failing on LLVM 13: https://github.com/rust-lang/rust/issues/88520 +#[cfg(not(target_arch = "powerpc64"))] +#[cfg(test)] +mod tests { + use super::rint; + + #[test] + fn negative_zero() { + assert_eq!(rint(-0.0_f64).to_bits(), (-0.0_f64).to_bits()); + } + + #[test] + fn sanity_check() { + assert_eq!(rint(-1.0), -1.0); + assert_eq!(rint(2.8), 3.0); + assert_eq!(rint(-0.5), -0.0); + assert_eq!(rint(0.5), 0.0); + assert_eq!(rint(-1.5), -2.0); + assert_eq!(rint(1.5), 2.0); + } +} diff --git a/library/compiler-builtins/libm/src/math/rintf.rs b/library/compiler-builtins/libm/src/math/rintf.rs new file mode 100644 index 000000000000..d427793f7fc6 --- /dev/null +++ b/library/compiler-builtins/libm/src/math/rintf.rs @@ -0,0 +1,48 @@ +#[cfg_attr(all(test, assert_no_panic), no_panic::no_panic)] +pub fn rintf(x: f32) -> f32 { + let one_over_e = 1.0 / f32::EPSILON; + let as_u32: u32 = x.to_bits(); + let exponent: u32 = as_u32 >> 23 & 0xff; + let is_positive = (as_u32 >> 31) == 0; + if exponent >= 0x7f + 23 { + x + } else { + let ans = if is_positive { + x + one_over_e - one_over_e + } else { + x - one_over_e + one_over_e + }; + + if ans == 0.0 { + if is_positive { + 0.0 + } else { + -0.0 + } + } else { + ans + } + } +} + +// PowerPC tests are failing on LLVM 13: https://github.com/rust-lang/rust/issues/88520 +#[cfg(not(target_arch = "powerpc64"))] +#[cfg(test)] +mod tests { + use super::rintf; + + #[test] + fn negative_zero() { + assert_eq!(rintf(-0.0_f32).to_bits(), (-0.0_f32).to_bits()); + } + + #[test] + fn sanity_check() { + assert_eq!(rintf(-1.0), -1.0); + assert_eq!(rintf(2.8), 3.0); + assert_eq!(rintf(-0.5), -0.0); + assert_eq!(rintf(0.5), 0.0); + assert_eq!(rintf(-1.5), -2.0); + assert_eq!(rintf(1.5), 2.0); + } +}