approx delta different when running in miri

Author: LorrensP-2158466

library/std/tests/floats/f32.rs

@@ -22,6 +22,11 @@ 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_DETLA: f32 = if cfg!(miri) { 1e-4 } else { 1e-6 };
+
 #[allow(unused_macros)]
 macro_rules! assert_f32_biteq {
     ($left : expr, $right : expr) => {
@@ -446,7 +451,7 @@ fn test_powi() {
     assert_approx_eq!(
         (-3.1f32).powi(2),
         9.61,
-        1e-4 /* Miri float-non-det: Make tests pass for now */
+        APPROX_DETLA /* Miri float-non-det: Make tests pass for now */
     );
     assert_approx_eq!(5.9f32.powi(-2), 0.028727);
     assert_eq!(8.3f32.powi(0), 1.0);
@@ -464,13 +469,13 @@ fn test_powf() {
     assert_approx_eq!(
         3.4f32.powf(4.5),
         246.408218,
-        1e-4 /* Miri float-non-det: Make tests pass for now */
+        APPROX_DETLA /* Miri float-non-det: Make tests pass for now */
     );
     assert_approx_eq!(2.7f32.powf(-3.2), 0.041652);
     assert_approx_eq!(
         (-3.1f32).powf(2.0),
         9.61,
-        1e-4 /* Miri float-non-det: Make tests pass for now */
+        APPROX_DETLA /* Miri float-non-det: Make tests pass for now */
     );
     assert_approx_eq!(5.9f32.powf(-2.0), 0.028727);
     assert_eq!(8.3f32.powf(0.0), 1.0);
@@ -497,7 +502,7 @@ fn test_exp() {
     assert_approx_eq!(
         148.413162,
         5.0f32.exp(),
-        1e-4 /* Miri float-non-det: Make tests pass for now */
+        APPROX_DETLA /* Miri float-non-det: Make tests pass for now */
     );
 
     let inf: f32 = f32::INFINITY;
@@ -513,7 +518,7 @@ fn test_exp2() {
     assert_approx_eq!(
         32.0,
         5.0f32.exp2(),
-        1e-4 /* Miri float-non-det: Make tests pass for now */
+        APPROX_DETLA /* Miri float-non-det: Make tests pass for now */
     );
     assert_eq!(1.0, 0.0f32.exp2());
 
@@ -540,7 +545,7 @@ fn test_ln() {
     assert_approx_eq!(
         4.0f32.ln(),
         1.386294,
-        1e-4 /* Miri float-non-det: Make tests pass for now */
+        APPROX_DETLA /* Miri float-non-det: Make tests pass for now */
     );
 }
 
@@ -666,7 +671,7 @@ fn test_acosh() {
     assert_approx_eq!(
         60.0f32,
         60.0f32.cosh().acosh(),
-        1e-4 /* Miri float-non-det: Make tests pass for now */
+        APPROX_DETLA /* Miri float-non-det: Make tests pass for now */
     );
 }
 
@@ -749,7 +754,7 @@ fn test_real_consts() {
     assert_approx_eq!(
         frac_pi_3,
         pi / 3f32,
-        1e-4 /* Miri float-non-det: Make tests pass for now */
+        APPROX_DETLA /* Miri float-non-det: Make tests pass for now */
     );
     assert_approx_eq!(frac_pi_4, pi / 4f32);
     assert_approx_eq!(frac_pi_6, pi / 6f32);