Test new floating point bit casts

src/test/ui/consts/const-float-bits-conv.rs

@@ -0,0 +1,93 @@
+// -Zmir-opt-level=0
+// run-pass
+
+#![feature(const_panic)]
+#![feature(const_float_bits_conv)]
+#![feature(const_float_classify)]
+
+// Don't promote
+const fn nop<T>(x: T) -> T { x }
+
+macro_rules! const_assert {
+    ($a:expr) => {
+        {
+            const _: () = assert!($a);
+            assert!(nop($a));
+        }
+    };
+    ($a:expr, $b:expr) => {
+        {
+            const _: () = assert!($a == $b);
+            assert_eq!(nop($a), nop($b));
+        }
+    };
+}
+
+fn f32() {
+    const_assert!((1f32).to_bits(), 0x3f800000);
+    const_assert!(u32::from_be_bytes(1f32.to_be_bytes()), 0x3f800000);
+    const_assert!((12.5f32).to_bits(), 0x41480000);
+    const_assert!(u32::from_le_bytes(12.5f32.to_le_bytes()), 0x41480000);
+    const_assert!((1337f32).to_bits(), 0x44a72000);
+    const_assert!(u32::from_ne_bytes(1337f32.to_ne_bytes()), 0x44a72000);
+    const_assert!((-14.25f32).to_bits(), 0xc1640000);
+    const_assert!(f32::from_bits(0x3f800000), 1.0);
+    const_assert!(f32::from_be_bytes(0x3f800000u32.to_be_bytes()), 1.0);
+    const_assert!(f32::from_bits(0x41480000), 12.5);
+    const_assert!(f32::from_le_bytes(0x41480000u32.to_le_bytes()), 12.5);
+    const_assert!(f32::from_bits(0x44a72000), 1337.0);
+    const_assert!(f32::from_ne_bytes(0x44a72000u32.to_ne_bytes()), 1337.0);
+    const_assert!(f32::from_bits(0xc1640000), -14.25);
+
+    // Check that NaNs roundtrip their bits regardless of signalingness
+    // 0xA is 0b1010; 0x5 is 0b0101 -- so these two together clobbers all the mantissa bits
+    const MASKED_NAN1: u32 = f32::NAN.to_bits() ^ 0x002A_AAAA;
+    const MASKED_NAN2: u32 = f32::NAN.to_bits() ^ 0x0055_5555;
+
+    const_assert!(f32::from_bits(MASKED_NAN1).is_nan());
+    const_assert!(f32::from_bits(MASKED_NAN1).is_nan());
+
+    // LLVM does not guarantee that loads and stores of NaNs preserve their exact bit pattern.
+    // In practice, this seems to only cause a problem on x86, since the most widely used calling
+    // convention mandates that floating point values are returned on the x87 FPU stack. See #73328.
+    if !cfg!(target_arch = "x86") {
+        const_assert!(f32::from_bits(MASKED_NAN1).to_bits(), MASKED_NAN1);
+        const_assert!(f32::from_bits(MASKED_NAN2).to_bits(), MASKED_NAN2);
+    }
+}
+
+fn f64() {
+    const_assert!((1f64).to_bits(), 0x3ff0000000000000);
+    const_assert!(u64::from_be_bytes(1f64.to_be_bytes()), 0x3ff0000000000000);
+    const_assert!((12.5f64).to_bits(), 0x4029000000000000);
+    const_assert!(u64::from_le_bytes(12.5f64.to_le_bytes()), 0x4029000000000000);
+    const_assert!((1337f64).to_bits(), 0x4094e40000000000);
+    const_assert!(u64::from_ne_bytes(1337f64.to_ne_bytes()), 0x4094e40000000000);
+    const_assert!((-14.25f64).to_bits(), 0xc02c800000000000);
+    const_assert!(f64::from_bits(0x3ff0000000000000), 1.0);
+    const_assert!(f64::from_be_bytes(0x3ff0000000000000u64.to_be_bytes()), 1.0);
+    const_assert!(f64::from_bits(0x4029000000000000), 12.5);
+    const_assert!(f64::from_le_bytes(0x4029000000000000u64.to_le_bytes()), 12.5);
+    const_assert!(f64::from_bits(0x4094e40000000000), 1337.0);
+    const_assert!(f64::from_ne_bytes(0x4094e40000000000u64.to_ne_bytes()), 1337.0);
+    const_assert!(f64::from_bits(0xc02c800000000000), -14.25);
+
+    // Check that NaNs roundtrip their bits regardless of signalingness
+    // 0xA is 0b1010; 0x5 is 0b0101 -- so these two together clobbers all the mantissa bits
+    const MASKED_NAN1: u64 = f64::NAN.to_bits() ^ 0x000A_AAAA_AAAA_AAAA;
+    const MASKED_NAN2: u64 = f64::NAN.to_bits() ^ 0x0005_5555_5555_5555;
+
+    const_assert!(f64::from_bits(MASKED_NAN1).is_nan());
+    const_assert!(f64::from_bits(MASKED_NAN1).is_nan());
+
+    // See comment above.
+    if !cfg!(target_arch = "x86") {
+        const_assert!(f64::from_bits(MASKED_NAN1).to_bits(), MASKED_NAN1);
+        const_assert!(f64::from_bits(MASKED_NAN2).to_bits(), MASKED_NAN2);
+    }
+}
+
+fn main() {
+    f32();
+    f64();
+}

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

@@ -0,0 +1,77 @@
+// -Zmir-opt-level=0
+// run-pass
+
+#![feature(const_panic)]
+#![feature(const_float_bits_conv)]
+#![feature(const_float_classify)]
+#![feature(const_trait_impl)]
+#![allow(incomplete_features)]
+
+// Don't promote
+const fn nop<T>(x: T) -> T { x }
+
+macro_rules! const_assert {
+    ($a:expr, $b:expr) => {
+        {
+            const _: () = assert!($a == $b);
+            assert_eq!(nop($a), nop($b));
+        }
+    };
+}
+
+macro_rules! suite {
+    ( $( $tt:tt )* ) => {
+        fn f32() {
+            suite_inner!(f32 $($tt)*);
+        }
+
+        fn f64() {
+            suite_inner!(f64 $($tt)*);
+        }
+    }
+
+}
+
+macro_rules! suite_inner {
+    (
+        $ty:ident [$( $fn:ident ),*]
+        $val:expr => [$($out:ident),*]
+
+        $( $tail:tt )*
+    ) => {
+        $( const_assert!($ty::$fn($val), $out); )*
+        suite_inner!($ty [$($fn),*] $($tail)*)
+    };
+
+    ( $ty:ident [$( $fn:ident ),*]) => {};
+}
+
+#[derive(Debug)]
+struct NonDet;
+
+impl const PartialEq<NonDet> for bool {
+    fn eq(&self, _: &NonDet) -> bool {
+        true
+    }
+}
+
+// The result of the `is_sign` methods are not checked for correctness, since LLVM does not
+// guarantee anything about the signedness of NaNs. See
+// https://github.com/rust-lang/rust/issues/55131.
+
+suite! {
+                   [is_nan, is_infinite, is_finite, is_normal, is_sign_positive, is_sign_negative]
+     -0.0 / 0.0 => [  true,       false,     false,     false,           NonDet,           NonDet]
+      0.0 / 0.0 => [  true,       false,     false,     false,           NonDet,           NonDet]
+            1.0 => [ false,       false,      true,      true,             true,            false]
+           -1.0 => [ false,       false,      true,      true,            false,             true]
+            0.0 => [ false,       false,      true,     false,             true,            false]
+           -0.0 => [ false,       false,      true,     false,            false,             true]
+      1.0 / 0.0 => [ false,        true,     false,     false,             true,            false]
+     -1.0 / 0.0 => [ false,        true,     false,     false,            false,             true]
+}
+
+fn main() {
+    f32();
+    f64();
+}