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Test new floating point bit casts
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‎src/test/ui/consts/const-float-bits-conv.rs

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// -Zmir-opt-level=0
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// run-pass
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#![feature(const_panic)]
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#![feature(const_float_bits_conv)]
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#![feature(const_float_classify)]
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// Don't promote
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const fn nop<T>(x: T) -> T { x }
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macro_rules! const_assert {
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($a:expr) => {
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{
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const _: () = assert!($a);
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assert!(nop($a));
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}
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};
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($a:expr, $b:expr) => {
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{
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const _: () = assert!($a == $b);
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assert_eq!(nop($a), nop($b));
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}
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};
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}
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fn f32() {
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const_assert!((1f32).to_bits(), 0x3f800000);
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const_assert!(u32::from_be_bytes(1f32.to_be_bytes()), 0x3f800000);
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const_assert!((12.5f32).to_bits(), 0x41480000);
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const_assert!(u32::from_le_bytes(12.5f32.to_le_bytes()), 0x41480000);
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const_assert!((1337f32).to_bits(), 0x44a72000);
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const_assert!(u32::from_ne_bytes(1337f32.to_ne_bytes()), 0x44a72000);
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const_assert!((-14.25f32).to_bits(), 0xc1640000);
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const_assert!(f32::from_bits(0x3f800000), 1.0);
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const_assert!(f32::from_be_bytes(0x3f800000u32.to_be_bytes()), 1.0);
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const_assert!(f32::from_bits(0x41480000), 12.5);
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const_assert!(f32::from_le_bytes(0x41480000u32.to_le_bytes()), 12.5);
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const_assert!(f32::from_bits(0x44a72000), 1337.0);
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const_assert!(f32::from_ne_bytes(0x44a72000u32.to_ne_bytes()), 1337.0);
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const_assert!(f32::from_bits(0xc1640000), -14.25);
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// Check that NaNs roundtrip their bits regardless of signalingness
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// 0xA is 0b1010; 0x5 is 0b0101 -- so these two together clobbers all the mantissa bits
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const MASKED_NAN1: u32 = f32::NAN.to_bits() ^ 0x002A_AAAA;
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const MASKED_NAN2: u32 = f32::NAN.to_bits() ^ 0x0055_5555;
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const_assert!(f32::from_bits(MASKED_NAN1).is_nan());
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const_assert!(f32::from_bits(MASKED_NAN1).is_nan());
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// LLVM does not guarantee that loads and stores of NaNs preserve their exact bit pattern.
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// In practice, this seems to only cause a problem on x86, since the most widely used calling
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// convention mandates that floating point values are returned on the x87 FPU stack. See #73328.
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if !cfg!(target_arch = "x86") {
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const_assert!(f32::from_bits(MASKED_NAN1).to_bits(), MASKED_NAN1);
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const_assert!(f32::from_bits(MASKED_NAN2).to_bits(), MASKED_NAN2);
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}
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}
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fn f64() {
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const_assert!((1f64).to_bits(), 0x3ff0000000000000);
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const_assert!(u64::from_be_bytes(1f64.to_be_bytes()), 0x3ff0000000000000);
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const_assert!((12.5f64).to_bits(), 0x4029000000000000);
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const_assert!(u64::from_le_bytes(12.5f64.to_le_bytes()), 0x4029000000000000);
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const_assert!((1337f64).to_bits(), 0x4094e40000000000);
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const_assert!(u64::from_ne_bytes(1337f64.to_ne_bytes()), 0x4094e40000000000);
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const_assert!((-14.25f64).to_bits(), 0xc02c800000000000);
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const_assert!(f64::from_bits(0x3ff0000000000000), 1.0);
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const_assert!(f64::from_be_bytes(0x3ff0000000000000u64.to_be_bytes()), 1.0);
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const_assert!(f64::from_bits(0x4029000000000000), 12.5);
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const_assert!(f64::from_le_bytes(0x4029000000000000u64.to_le_bytes()), 12.5);
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const_assert!(f64::from_bits(0x4094e40000000000), 1337.0);
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const_assert!(f64::from_ne_bytes(0x4094e40000000000u64.to_ne_bytes()), 1337.0);
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const_assert!(f64::from_bits(0xc02c800000000000), -14.25);
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// Check that NaNs roundtrip their bits regardless of signalingness
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// 0xA is 0b1010; 0x5 is 0b0101 -- so these two together clobbers all the mantissa bits
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const MASKED_NAN1: u64 = f64::NAN.to_bits() ^ 0x000A_AAAA_AAAA_AAAA;
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const MASKED_NAN2: u64 = f64::NAN.to_bits() ^ 0x0005_5555_5555_5555;
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const_assert!(f64::from_bits(MASKED_NAN1).is_nan());
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const_assert!(f64::from_bits(MASKED_NAN1).is_nan());
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// See comment above.
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if !cfg!(target_arch = "x86") {
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const_assert!(f64::from_bits(MASKED_NAN1).to_bits(), MASKED_NAN1);
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const_assert!(f64::from_bits(MASKED_NAN2).to_bits(), MASKED_NAN2);
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}
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}
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fn main() {
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f32();
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f64();
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}

‎src/test/ui/consts/const-float-classify.rs

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// -Zmir-opt-level=0
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// run-pass
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#![feature(const_panic)]
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#![feature(const_float_bits_conv)]
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#![feature(const_float_classify)]
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#![feature(const_trait_impl)]
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#![allow(incomplete_features)]
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// Don't promote
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const fn nop<T>(x: T) -> T { x }
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macro_rules! const_assert {
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($a:expr, $b:expr) => {
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{
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const _: () = assert!($a == $b);
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assert_eq!(nop($a), nop($b));
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}
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};
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}
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macro_rules! suite {
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( $( $tt:tt )* ) => {
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fn f32() {
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suite_inner!(f32 $($tt)*);
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}
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fn f64() {
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suite_inner!(f64 $($tt)*);
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}
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}
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}
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macro_rules! suite_inner {
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(
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$ty:ident [$( $fn:ident ),*]
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$val:expr => [$($out:ident),*]
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$( $tail:tt )*
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) => {
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$( const_assert!($ty::$fn($val), $out); )*
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suite_inner!($ty [$($fn),*] $($tail)*)
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};
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( $ty:ident [$( $fn:ident ),*]) => {};
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}
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#[derive(Debug)]
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struct NonDet;
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impl const PartialEq<NonDet> for bool {
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fn eq(&self, _: &NonDet) -> bool {
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true
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}
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}
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// The result of the `is_sign` methods are not checked for correctness, since LLVM does not
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// guarantee anything about the signedness of NaNs. See
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// https://github.com/rust-lang/rust/issues/55131.
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suite! {
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[is_nan, is_infinite, is_finite, is_normal, is_sign_positive, is_sign_negative]
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-0.0 / 0.0 => [ true, false, false, false, NonDet, NonDet]
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0.0 / 0.0 => [ true, false, false, false, NonDet, NonDet]
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1.0 => [ false, false, true, true, true, false]
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-1.0 => [ false, false, true, true, false, true]
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0.0 => [ false, false, true, false, true, false]
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-0.0 => [ false, false, true, false, false, true]
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1.0 / 0.0 => [ false, true, false, false, true, false]
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-1.0 / 0.0 => [ false, true, false, false, false, true]
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}
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fn main() {
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f32();
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f64();
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}

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