Rollup merge of #145468 - karolzwolak:float-tests-dedup, r=tgross35

dedup recip, powi, to_degrees, and to_radians float tests

Deduplicates recip, powi, to_degrees, and to_radians float tests.
I had to fiddle and slightly increase the tolerances for a few comparisons, so maybe not all of the tests are worth deduplicating.

Part of rust-lang/rust#141726.
Best reviewed commit-by-commit.

r? `@tgross35`

5 files changed, 105 insertions, 243 deletions

diff --git a/library/coretests/tests/floats/f128.rs b/library/coretests/tests/floats/f128.rs
index ac4a2066530..c173d7f0ae0 100644
--- a/library/coretests/tests/floats/f128.rs
+++ b/library/coretests/tests/floats/f128.rs
@@ -1,18 +1,18 @@
 // FIXME(f16_f128): only tested on platforms that have symbols and aren't buggy
 #![cfg(target_has_reliable_f128)]
 
-use std::f128::consts;
-
 use super::{assert_approx_eq, assert_biteq};
 
 // Note these tolerances make sense around zero, but not for more extreme exponents.
 
 /// Default tolerances. Works for values that should be near precise but not exact. Roughly
 /// the precision carried by `100 * 100`.
+#[allow(unused)]
 const TOL: f128 = 1e-12;
 
 /// For operations that are near exact, usually not involving math of different
 /// signs.
+#[allow(unused)]
 const TOL_PRECISE: f128 = 1e-28;
 
 /// First pattern over the mantissa
@@ -44,70 +44,12 @@ fn test_mul_add() {
 
 #[test]
 #[cfg(any(miri, target_has_reliable_f128_math))]
-fn test_recip() {
-    let nan: f128 = f128::NAN;
-    let inf: f128 = f128::INFINITY;
-    let neg_inf: f128 = f128::NEG_INFINITY;
-    assert_biteq!(1.0f128.recip(), 1.0);
-    assert_biteq!(2.0f128.recip(), 0.5);
-    assert_biteq!((-0.4f128).recip(), -2.5);
-    assert_biteq!(0.0f128.recip(), inf);
+fn test_max_recip() {
     assert_approx_eq!(
         f128::MAX.recip(),
         8.40525785778023376565669454330438228902076605e-4933,
         1e-4900
     );
-    assert!(nan.recip().is_nan());
-    assert_biteq!(inf.recip(), 0.0);
-    assert_biteq!(neg_inf.recip(), -0.0);
-}
-
-#[test]
-#[cfg(not(miri))]
-#[cfg(target_has_reliable_f128_math)]
-fn test_powi() {
-    let nan: f128 = f128::NAN;
-    let inf: f128 = f128::INFINITY;
-    let neg_inf: f128 = f128::NEG_INFINITY;
-    assert_biteq!(1.0f128.powi(1), 1.0);
-    assert_approx_eq!((-3.1f128).powi(2), 9.6100000000000005506706202140776519387, TOL);
-    assert_approx_eq!(5.9f128.powi(-2), 0.028727377190462507313100483690639638451, TOL);
-    assert_biteq!(8.3f128.powi(0), 1.0);
-    assert!(nan.powi(2).is_nan());
-    assert_biteq!(inf.powi(3), inf);
-    assert_biteq!(neg_inf.powi(2), inf);
-}
-
-#[test]
-fn test_to_degrees() {
-    let pi: f128 = consts::PI;
-    let nan: f128 = f128::NAN;
-    let inf: f128 = f128::INFINITY;
-    let neg_inf: f128 = f128::NEG_INFINITY;
-    assert_biteq!(0.0f128.to_degrees(), 0.0);
-    assert_approx_eq!((-5.8f128).to_degrees(), -332.31552117587745090765431723855668471, TOL);
-    assert_approx_eq!(pi.to_degrees(), 180.0, TOL);
-    assert!(nan.to_degrees().is_nan());
-    assert_biteq!(inf.to_degrees(), inf);
-    assert_biteq!(neg_inf.to_degrees(), neg_inf);
-    assert_biteq!(1_f128.to_degrees(), 57.2957795130823208767981548141051703);
-}
-
-#[test]
-fn test_to_radians() {
-    let pi: f128 = consts::PI;
-    let nan: f128 = f128::NAN;
-    let inf: f128 = f128::INFINITY;
-    let neg_inf: f128 = f128::NEG_INFINITY;
-    assert_biteq!(0.0f128.to_radians(), 0.0);
-    assert_approx_eq!(154.6f128.to_radians(), 2.6982790235832334267135442069489767804, TOL);
-    assert_approx_eq!((-332.31f128).to_radians(), -5.7999036373023566567593094812182763013, TOL);
-    // check approx rather than exact because round trip for pi doesn't fall on an exactly
-    // representable value (unlike `f32` and `f64`).
-    assert_approx_eq!(180.0f128.to_radians(), pi, TOL_PRECISE);
-    assert!(nan.to_radians().is_nan());
-    assert_biteq!(inf.to_radians(), inf);
-    assert_biteq!(neg_inf.to_radians(), neg_inf);
 }
 
 #[test]
diff --git a/library/coretests/tests/floats/f16.rs b/library/coretests/tests/floats/f16.rs
index bb9c8a002fe..c12de7221ba 100644
--- a/library/coretests/tests/floats/f16.rs
+++ b/library/coretests/tests/floats/f16.rs
@@ -1,8 +1,6 @@
 // FIXME(f16_f128): only tested on platforms that have symbols and aren't buggy
 #![cfg(target_has_reliable_f16)]
 
-use std::f16::consts;
-
 use super::{assert_approx_eq, assert_biteq};
 
 /// Tolerance for results on the order of 10.0e-2
@@ -50,64 +48,8 @@ fn test_mul_add() {
 
 #[test]
 #[cfg(any(miri, target_has_reliable_f16_math))]
-fn test_recip() {
-    let nan: f16 = f16::NAN;
-    let inf: f16 = f16::INFINITY;
-    let neg_inf: f16 = f16::NEG_INFINITY;
-    assert_biteq!(1.0f16.recip(), 1.0);
-    assert_biteq!(2.0f16.recip(), 0.5);
-    assert_biteq!((-0.4f16).recip(), -2.5);
-    assert_biteq!(0.0f16.recip(), inf);
+fn test_max_recip() {
     assert_approx_eq!(f16::MAX.recip(), 1.526624e-5f16, 1e-4);
-    assert!(nan.recip().is_nan());
-    assert_biteq!(inf.recip(), 0.0);
-    assert_biteq!(neg_inf.recip(), -0.0);
-}
-
-#[test]
-#[cfg(not(miri))]
-#[cfg(target_has_reliable_f16_math)]
-fn test_powi() {
-    let nan: f16 = f16::NAN;
-    let inf: f16 = f16::INFINITY;
-    let neg_inf: f16 = f16::NEG_INFINITY;
-    assert_biteq!(1.0f16.powi(1), 1.0);
-    assert_approx_eq!((-3.1f16).powi(2), 9.61, TOL_0);
-    assert_approx_eq!(5.9f16.powi(-2), 0.028727, TOL_N2);
-    assert_biteq!(8.3f16.powi(0), 1.0);
-    assert!(nan.powi(2).is_nan());
-    assert_biteq!(inf.powi(3), inf);
-    assert_biteq!(neg_inf.powi(2), inf);
-}
-
-#[test]
-fn test_to_degrees() {
-    let pi: f16 = consts::PI;
-    let nan: f16 = f16::NAN;
-    let inf: f16 = f16::INFINITY;
-    let neg_inf: f16 = f16::NEG_INFINITY;
-    assert_biteq!(0.0f16.to_degrees(), 0.0);
-    assert_approx_eq!((-5.8f16).to_degrees(), -332.315521, TOL_P2);
-    assert_approx_eq!(pi.to_degrees(), 180.0, TOL_P2);
-    assert!(nan.to_degrees().is_nan());
-    assert_biteq!(inf.to_degrees(), inf);
-    assert_biteq!(neg_inf.to_degrees(), neg_inf);
-    assert_biteq!(1_f16.to_degrees(), 57.2957795130823208767981548141051703);
-}
-
-#[test]
-fn test_to_radians() {
-    let pi: f16 = consts::PI;
-    let nan: f16 = f16::NAN;
-    let inf: f16 = f16::INFINITY;
-    let neg_inf: f16 = f16::NEG_INFINITY;
-    assert_biteq!(0.0f16.to_radians(), 0.0);
-    assert_approx_eq!(154.6f16.to_radians(), 2.698279, TOL_0);
-    assert_approx_eq!((-332.31f16).to_radians(), -5.799903, TOL_0);
-    assert_approx_eq!(180.0f16.to_radians(), pi, TOL_0);
-    assert!(nan.to_radians().is_nan());
-    assert_biteq!(inf.to_radians(), inf);
-    assert_biteq!(neg_inf.to_radians(), neg_inf);
 }
 
 #[test]
diff --git a/library/coretests/tests/floats/f32.rs b/library/coretests/tests/floats/f32.rs
index e77e44655dc..b79295f470d 100644
--- a/library/coretests/tests/floats/f32.rs
+++ b/library/coretests/tests/floats/f32.rs
@@ -1,5 +1,4 @@
 use core::f32;
-use core::f32::consts;
 
 use super::{assert_approx_eq, assert_biteq};
 
@@ -9,11 +8,6 @@ const NAN_MASK1: u32 = 0x002a_aaaa;
 /// Second pattern over the mantissa
 const NAN_MASK2: u32 = 0x0055_5555;
 
-/// Miri adds some extra errors to float functions; make sure the tests still pass.
-/// These values are purely used as a canary to test against and are thus not a stable guarantee Rust provides.
-/// They serve as a way to get an idea of the real precision of floating point operations on different platforms.
-const APPROX_DELTA: f32 = if cfg!(miri) { 1e-4 } else { 1e-6 };
-
 // FIXME(#140515): mingw has an incorrect fma https://sourceforge.net/p/mingw-w64/bugs/848/
 #[cfg_attr(all(target_os = "windows", target_env = "gnu", not(target_abi = "llvm")), ignore)]
 #[test]
@@ -33,64 +27,6 @@ fn test_mul_add() {
 }
 
 #[test]
-fn test_recip() {
-    let nan: f32 = f32::NAN;
-    let inf: f32 = f32::INFINITY;
-    let neg_inf: f32 = f32::NEG_INFINITY;
-    assert_biteq!(1.0f32.recip(), 1.0);
-    assert_biteq!(2.0f32.recip(), 0.5);
-    assert_biteq!((-0.4f32).recip(), -2.5);
-    assert_biteq!(0.0f32.recip(), inf);
-    assert!(nan.recip().is_nan());
-    assert_biteq!(inf.recip(), 0.0);
-    assert_biteq!(neg_inf.recip(), -0.0);
-}
-
-#[test]
-fn test_powi() {
-    let nan: f32 = f32::NAN;
-    let inf: f32 = f32::INFINITY;
-    let neg_inf: f32 = f32::NEG_INFINITY;
-    assert_approx_eq!(1.0f32.powi(1), 1.0);
-    assert_approx_eq!((-3.1f32).powi(2), 9.61, APPROX_DELTA);
-    assert_approx_eq!(5.9f32.powi(-2), 0.028727);
-    assert_biteq!(8.3f32.powi(0), 1.0);
-    assert!(nan.powi(2).is_nan());
-    assert_biteq!(inf.powi(3), inf);
-    assert_biteq!(neg_inf.powi(2), inf);
-}
-
-#[test]
-fn test_to_degrees() {
-    let pi: f32 = consts::PI;
-    let nan: f32 = f32::NAN;
-    let inf: f32 = f32::INFINITY;
-    let neg_inf: f32 = f32::NEG_INFINITY;
-    assert_biteq!(0.0f32.to_degrees(), 0.0);
-    assert_approx_eq!((-5.8f32).to_degrees(), -332.315521);
-    assert_biteq!(pi.to_degrees(), 180.0);
-    assert!(nan.to_degrees().is_nan());
-    assert_biteq!(inf.to_degrees(), inf);
-    assert_biteq!(neg_inf.to_degrees(), neg_inf);
-    assert_biteq!(1_f32.to_degrees(), 57.2957795130823208767981548141051703);
-}
-
-#[test]
-fn test_to_radians() {
-    let pi: f32 = consts::PI;
-    let nan: f32 = f32::NAN;
-    let inf: f32 = f32::INFINITY;
-    let neg_inf: f32 = f32::NEG_INFINITY;
-    assert_biteq!(0.0f32.to_radians(), 0.0);
-    assert_approx_eq!(154.6f32.to_radians(), 2.698279);
-    assert_approx_eq!((-332.31f32).to_radians(), -5.799903);
-    assert_biteq!(180.0f32.to_radians(), pi);
-    assert!(nan.to_radians().is_nan());
-    assert_biteq!(inf.to_radians(), inf);
-    assert_biteq!(neg_inf.to_radians(), neg_inf);
-}
-
-#[test]
 fn test_float_bits_conv() {
     assert_eq!((1f32).to_bits(), 0x3f800000);
     assert_eq!((12.5f32).to_bits(), 0x41480000);
diff --git a/library/coretests/tests/floats/f64.rs b/library/coretests/tests/floats/f64.rs
index fea9cc19b39..a2540586328 100644
--- a/library/coretests/tests/floats/f64.rs
+++ b/library/coretests/tests/floats/f64.rs
@@ -1,5 +1,4 @@
 use core::f64;
-use core::f64::consts;
 
 use super::{assert_approx_eq, assert_biteq};
 
@@ -28,63 +27,6 @@ fn test_mul_add() {
 }
 
 #[test]
-fn test_recip() {
-    let nan: f64 = f64::NAN;
-    let inf: f64 = f64::INFINITY;
-    let neg_inf: f64 = f64::NEG_INFINITY;
-    assert_biteq!(1.0f64.recip(), 1.0);
-    assert_biteq!(2.0f64.recip(), 0.5);
-    assert_biteq!((-0.4f64).recip(), -2.5);
-    assert_biteq!(0.0f64.recip(), inf);
-    assert!(nan.recip().is_nan());
-    assert_biteq!(inf.recip(), 0.0);
-    assert_biteq!(neg_inf.recip(), -0.0);
-}
-
-#[test]
-fn test_powi() {
-    let nan: f64 = f64::NAN;
-    let inf: f64 = f64::INFINITY;
-    let neg_inf: f64 = f64::NEG_INFINITY;
-    assert_approx_eq!(1.0f64.powi(1), 1.0);
-    assert_approx_eq!((-3.1f64).powi(2), 9.61);
-    assert_approx_eq!(5.9f64.powi(-2), 0.028727);
-    assert_biteq!(8.3f64.powi(0), 1.0);
-    assert!(nan.powi(2).is_nan());
-    assert_biteq!(inf.powi(3), inf);
-    assert_biteq!(neg_inf.powi(2), inf);
-}
-
-#[test]
-fn test_to_degrees() {
-    let pi: f64 = consts::PI;
-    let nan: f64 = f64::NAN;
-    let inf: f64 = f64::INFINITY;
-    let neg_inf: f64 = f64::NEG_INFINITY;
-    assert_biteq!(0.0f64.to_degrees(), 0.0);
-    assert_approx_eq!((-5.8f64).to_degrees(), -332.315521);
-    assert_biteq!(pi.to_degrees(), 180.0);
-    assert!(nan.to_degrees().is_nan());
-    assert_biteq!(inf.to_degrees(), inf);
-    assert_biteq!(neg_inf.to_degrees(), neg_inf);
-}
-
-#[test]
-fn test_to_radians() {
-    let pi: f64 = consts::PI;
-    let nan: f64 = f64::NAN;
-    let inf: f64 = f64::INFINITY;
-    let neg_inf: f64 = f64::NEG_INFINITY;
-    assert_biteq!(0.0f64.to_radians(), 0.0);
-    assert_approx_eq!(154.6f64.to_radians(), 2.698279);
-    assert_approx_eq!((-332.31f64).to_radians(), -5.799903);
-    assert_biteq!(180.0f64.to_radians(), pi);
-    assert!(nan.to_radians().is_nan());
-    assert_biteq!(inf.to_radians(), inf);
-    assert_biteq!(neg_inf.to_radians(), neg_inf);
-}
-
-#[test]
 fn test_float_bits_conv() {
     assert_eq!((1f64).to_bits(), 0x3ff0000000000000);
     assert_eq!((12.5f64).to_bits(), 0x4029000000000000);
diff --git a/library/coretests/tests/floats/mod.rs b/library/coretests/tests/floats/mod.rs
index 2c2a07920d0..5f59cb9cce3 100644
--- a/library/coretests/tests/floats/mod.rs
+++ b/library/coretests/tests/floats/mod.rs
@@ -1,13 +1,20 @@
 use std::num::FpCategory as Fp;
 use std::ops::{Add, Div, Mul, Rem, Sub};
 
-trait TestableFloat {
+trait TestableFloat: Sized {
     /// Unsigned int with the same size, for converting to/from bits.
     type Int;
     /// Set the default tolerance for float comparison based on the type.
     const APPROX: Self;
+    /// Allow looser tolerance for f32 on miri
+    const POWI_APPROX: Self = Self::APPROX;
+    /// Allow looser tolerance for f16
+    const _180_TO_RADIANS_APPROX: Self = Self::APPROX;
+    /// Allow for looser tolerance for f16
+    const PI_TO_DEGREES_APPROX: Self = Self::APPROX;
     const ZERO: Self;
     const ONE: Self;
+    const PI: Self;
     const MIN_POSITIVE_NORMAL: Self;
     const MAX_SUBNORMAL: Self;
     /// Smallest number
@@ -25,8 +32,11 @@ trait TestableFloat {
 impl TestableFloat for f16 {
     type Int = u16;
     const APPROX: Self = 1e-3;
+    const _180_TO_RADIANS_APPROX: Self = 1e-2;
+    const PI_TO_DEGREES_APPROX: Self = 0.125;
     const ZERO: Self = 0.0;
     const ONE: Self = 1.0;
+    const PI: Self = std::f16::consts::PI;
     const MIN_POSITIVE_NORMAL: Self = Self::MIN_POSITIVE;
     const MAX_SUBNORMAL: Self = Self::MIN_POSITIVE.next_down();
     const TINY: Self = Self::from_bits(0x1);
@@ -39,8 +49,13 @@ impl TestableFloat for f16 {
 impl TestableFloat for f32 {
     type Int = u32;
     const APPROX: Self = 1e-6;
+    /// Miri adds some extra errors to float functions; make sure the tests still pass.
+    /// These values are purely used as a canary to test against and are thus not a stable guarantee Rust provides.
+    /// They serve as a way to get an idea of the real precision of floating point operations on different platforms.
+    const POWI_APPROX: Self = if cfg!(miri) { 1e-4 } else { Self::APPROX };
     const ZERO: Self = 0.0;
     const ONE: Self = 1.0;
+    const PI: Self = std::f32::consts::PI;
     const MIN_POSITIVE_NORMAL: Self = Self::MIN_POSITIVE;
     const MAX_SUBNORMAL: Self = Self::MIN_POSITIVE.next_down();
     const TINY: Self = Self::from_bits(0x1);
@@ -55,6 +70,7 @@ impl TestableFloat for f64 {
     const APPROX: Self = 1e-6;
     const ZERO: Self = 0.0;
     const ONE: Self = 1.0;
+    const PI: Self = std::f64::consts::PI;
     const MIN_POSITIVE_NORMAL: Self = Self::MIN_POSITIVE;
     const MAX_SUBNORMAL: Self = Self::MIN_POSITIVE.next_down();
     const TINY: Self = Self::from_bits(0x1);
@@ -69,6 +85,7 @@ impl TestableFloat for f128 {
     const APPROX: Self = 1e-9;
     const ZERO: Self = 0.0;
     const ONE: Self = 1.0;
+    const PI: Self = std::f128::consts::PI;
     const MIN_POSITIVE_NORMAL: Self = Self::MIN_POSITIVE;
     const MAX_SUBNORMAL: Self = Self::MIN_POSITIVE.next_down();
     const TINY: Self = Self::from_bits(0x1);
@@ -1340,3 +1357,86 @@ float_test! {
         assert_eq!(Ordering::Less, Float::total_cmp(&-s_nan(), &s_nan()));
     }
 }
+
+float_test! {
+    name: recip,
+    attrs: {
+        f16: #[cfg(any(miri, target_has_reliable_f16_math))],
+        f128: #[cfg(any(miri, target_has_reliable_f128_math))],
+    },
+    test<Float> {
+        let nan: Float = Float::NAN;
+        let inf: Float = Float::INFINITY;
+        let neg_inf: Float = Float::NEG_INFINITY;
+        assert_biteq!((1.0 as Float).recip(), 1.0);
+        assert_biteq!((2.0 as Float).recip(), 0.5);
+        assert_biteq!((-0.4 as Float).recip(), -2.5);
+        assert_biteq!((0.0 as Float).recip(), inf);
+        assert!(nan.recip().is_nan());
+        assert_biteq!(inf.recip(), 0.0);
+        assert_biteq!(neg_inf.recip(), -0.0);
+    }
+}
+
+float_test! {
+    name: powi,
+    attrs: {
+        const: #[cfg(false)],
+        f16: #[cfg(all(not(miri), target_has_reliable_f16_math))],
+        f128: #[cfg(all(not(miri), target_has_reliable_f128_math))],
+    },
+    test<Float> {
+        let nan: Float = Float::NAN;
+        let inf: Float = Float::INFINITY;
+        let neg_inf: Float = Float::NEG_INFINITY;
+        assert_approx_eq!(Float::ONE.powi(1), Float::ONE);
+        assert_approx_eq!((-3.1 as Float).powi(2), 9.6100000000000005506706202140776519387, Float::POWI_APPROX);
+        assert_approx_eq!((5.9 as Float).powi(-2), 0.028727377190462507313100483690639638451);
+        assert_biteq!((8.3 as Float).powi(0), Float::ONE);
+        assert!(nan.powi(2).is_nan());
+        assert_biteq!(inf.powi(3), inf);
+        assert_biteq!(neg_inf.powi(2), inf);
+    }
+}
+
+float_test! {
+    name: to_degrees,
+    attrs: {
+        f16: #[cfg(target_has_reliable_f16)],
+        f128: #[cfg(target_has_reliable_f128)],
+    },
+    test<Float> {
+        let pi: Float = Float::PI;
+        let nan: Float = Float::NAN;
+        let inf: Float = Float::INFINITY;
+        let neg_inf: Float = Float::NEG_INFINITY;
+        assert_biteq!((0.0 as Float).to_degrees(), 0.0);
+        assert_approx_eq!((-5.8 as Float).to_degrees(), -332.31552117587745090765431723855668471);
+        assert_approx_eq!(pi.to_degrees(), 180.0, Float::PI_TO_DEGREES_APPROX);
+        assert!(nan.to_degrees().is_nan());
+        assert_biteq!(inf.to_degrees(), inf);
+        assert_biteq!(neg_inf.to_degrees(), neg_inf);
+        assert_biteq!((1.0 as Float).to_degrees(), 57.2957795130823208767981548141051703);
+    }
+}
+
+float_test! {
+    name: to_radians,
+    attrs: {
+        f16: #[cfg(target_has_reliable_f16)],
+        f128: #[cfg(target_has_reliable_f128)],
+    },
+    test<Float> {
+        let pi: Float = Float::PI;
+        let nan: Float = Float::NAN;
+        let inf: Float = Float::INFINITY;
+        let neg_inf: Float = Float::NEG_INFINITY;
+        assert_biteq!((0.0 as Float).to_radians(), 0.0);
+        assert_approx_eq!((154.6 as Float).to_radians(), 2.6982790235832334267135442069489767804);
+        assert_approx_eq!((-332.31 as Float).to_radians(), -5.7999036373023566567593094812182763013);
+        assert_approx_eq!((180.0 as Float).to_radians(), pi, Float::_180_TO_RADIANS_APPROX);
+        assert!(nan.to_radians().is_nan());
+        assert_biteq!(inf.to_radians(), inf);
+        assert_biteq!(neg_inf.to_radians(), neg_inf);
+    }
+}