enable const-float-classify test, and test_next_up/down on 32bit x86

library/core/src/num/f16.rs

@@ -435,6 +435,7 @@ impl f16 {
         // WASM, see llvm/llvm-project#96437). These are platforms bugs, and Rust will misbehave on
         // such platforms, but we can at least try to make things seem as sane as possible by being
         // careful here.
+        // see also https://github.com./rust-lang/rust/issues/114479
         if self.is_infinite() {
             // Thus, a value may compare unequal to infinity, despite having a "full" exponent mask.
             FpCategory::Infinite

library/core/src/num/f32.rs

@@ -662,10 +662,7 @@ impl f32 {
         // hardware flushes subnormals to zero. These are platforms bugs, and Rust will misbehave on
         // such hardware, but we can at least try to make things seem as sane as possible by being
         // careful here.
-        //
-        // FIXME(jubilee): Using x87 operations is never necessary in order to function
-        // on x86 processors for Rust-to-Rust calls, so this issue should not happen.
-        // Code generation should be adjusted to use non-C calling conventions, avoiding this.
+        // see also https://github.com./rust-lang/rust/issues/114479
         if self.is_infinite() {
             // A value may compare unequal to infinity, despite having a "full" exponent mask.
             FpCategory::Infinite

library/core/src/num/f64.rs

@@ -660,10 +660,7 @@ impl f64 {
         // float semantics Rust relies on: x87 uses a too-large exponent, and some hardware flushes
         // subnormals to zero. These are platforms bugs, and Rust will misbehave on such hardware,
         // but we can at least try to make things seem as sane as possible by being careful here.
-        //
-        // FIXME(jubilee): Using x87 operations is never necessary in order to function
-        // on x86 processors for Rust-to-Rust calls, so this issue should not happen.
-        // Code generation should be adjusted to use non-C calling conventions, avoiding this.
+        // see also https://github.com./rust-lang/rust/issues/114479
         //
         // Thus, a value may compare unequal to infinity, despite having a "full" exponent mask.
         // And it may not be NaN, as it can simply be an "overextended" finite value.

library/std/src/f32/tests.rs

@@ -2,31 +2,24 @@ use crate::f32::consts;
 use crate::num::{FpCategory as Fp, *};
 
 /// Smallest number
-#[allow(dead_code)] // unused on x86
 const TINY_BITS: u32 = 0x1;
 
 /// Next smallest number
-#[allow(dead_code)] // unused on x86
 const TINY_UP_BITS: u32 = 0x2;
 
 /// Exponent = 0b11...10, Sifnificand 0b1111..10. Min val > 0
-#[allow(dead_code)] // unused on x86
 const MAX_DOWN_BITS: u32 = 0x7f7f_fffe;
 
 /// Zeroed exponent, full significant
-#[allow(dead_code)] // unused on x86
 const LARGEST_SUBNORMAL_BITS: u32 = 0x007f_ffff;
 
 /// Exponent = 0b1, zeroed significand
-#[allow(dead_code)] // unused on x86
 const SMALLEST_NORMAL_BITS: u32 = 0x0080_0000;
 
 /// First pattern over the mantissa
-#[allow(dead_code)] // unused on x86
 const NAN_MASK1: u32 = 0x002a_aaaa;
 
 /// Second pattern over the mantissa
-#[allow(dead_code)] // unused on x86
 const NAN_MASK2: u32 = 0x0055_5555;
 
 #[allow(unused_macros)]
@@ -353,9 +346,6 @@ fn test_is_sign_negative() {
     assert!((-f32::NAN).is_sign_negative());
 }
 
-// Ignore test on x87 floating point, these platforms do not guarantee NaN
-// payloads are preserved and flush denormals to zero, failing the tests.
-#[cfg(not(target_arch = "x86"))]
 #[test]
 fn test_next_up() {
     let tiny = f32::from_bits(TINY_BITS);
@@ -386,9 +376,6 @@ fn test_next_up() {
     assert_f32_biteq!(nan2.next_up(), nan2);
 }
 
-// Ignore test on x87 floating point, these platforms do not guarantee NaN
-// payloads are preserved and flush denormals to zero, failing the tests.
-#[cfg(not(target_arch = "x86"))]
 #[test]
 fn test_next_down() {
     let tiny = f32::from_bits(TINY_BITS);

library/std/src/f64/tests.rs

@@ -2,31 +2,24 @@ use crate::f64::consts;
 use crate::num::{FpCategory as Fp, *};
 
 /// Smallest number
-#[allow(dead_code)] // unused on x86
 const TINY_BITS: u64 = 0x1;
 
 /// Next smallest number
-#[allow(dead_code)] // unused on x86
 const TINY_UP_BITS: u64 = 0x2;
 
 /// Exponent = 0b11...10, Sifnificand 0b1111..10. Min val > 0
-#[allow(dead_code)] // unused on x86
 const MAX_DOWN_BITS: u64 = 0x7fef_ffff_ffff_fffe;
 
 /// Zeroed exponent, full significant
-#[allow(dead_code)] // unused on x86
 const LARGEST_SUBNORMAL_BITS: u64 = 0x000f_ffff_ffff_ffff;
 
 /// Exponent = 0b1, zeroed significand
-#[allow(dead_code)] // unused on x86
 const SMALLEST_NORMAL_BITS: u64 = 0x0010_0000_0000_0000;
 
 /// First pattern over the mantissa
-#[allow(dead_code)] // unused on x86
 const NAN_MASK1: u64 = 0x000a_aaaa_aaaa_aaaa;
 
 /// Second pattern over the mantissa
-#[allow(dead_code)] // unused on x86
 const NAN_MASK2: u64 = 0x0005_5555_5555_5555;
 
 #[allow(unused_macros)]
@@ -343,9 +336,6 @@ fn test_is_sign_negative() {
     assert!((-f64::NAN).is_sign_negative());
 }
 
-// Ignore test on x87 floating point, these platforms do not guarantee NaN
-// payloads are preserved and flush denormals to zero, failing the tests.
-#[cfg(not(target_arch = "x86"))]
 #[test]
 fn test_next_up() {
     let tiny = f64::from_bits(TINY_BITS);
@@ -375,9 +365,6 @@ fn test_next_up() {
     assert_f64_biteq!(nan2.next_up(), nan2);
 }
 
-// Ignore test on x87 floating point, these platforms do not guarantee NaN
-// payloads are preserved and flush denormals to zero, failing the tests.
-#[cfg(not(target_arch = "x86"))]
 #[test]
 fn test_next_down() {
     let tiny = f64::from_bits(TINY_BITS);