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//@ run-pass
//@ compile-flags: -Copt-level=0
// Test that floats (in particular signalling NaNs) are losslessly returned from functions.
fn main() {
// FIXME(#114479): LLVM miscompiles loading and storing `f32` and `f64` when SSE is disabled on
// x86.
if cfg!(not(all(target_arch = "x86", not(target_feature = "sse2")))) {
let bits_f32 = std::hint::black_box([
4.2_f32.to_bits(),
f32::INFINITY.to_bits(),
f32::NEG_INFINITY.to_bits(),
f32::NAN.to_bits(),
// These two masks cover all the mantissa bits. One of them is a signalling NaN, the
// other is quiet.
// Similar to the masks in `test_float_bits_conv` in library/std/src/f32/tests.rs
f32::NAN.to_bits() ^ 0x002A_AAAA,
f32::NAN.to_bits() ^ 0x0055_5555,
// Same as above but with the sign bit flipped.
f32::NAN.to_bits() ^ 0x802A_AAAA,
f32::NAN.to_bits() ^ 0x8055_5555,
]);
for bits in bits_f32 {
assert_eq!(identity(f32::from_bits(bits)).to_bits(), bits);
// Test types that are returned as scalar pairs.
assert_eq!(identity((f32::from_bits(bits), 42)).0.to_bits(), bits);
assert_eq!(identity((42, f32::from_bits(bits))).1.to_bits(), bits);
let (a, b) = identity((f32::from_bits(bits), f32::from_bits(bits)));
assert_eq!((a.to_bits(), b.to_bits()), (bits, bits));
}
let bits_f64 = std::hint::black_box([
4.2_f64.to_bits(),
f64::INFINITY.to_bits(),
f64::NEG_INFINITY.to_bits(),
f64::NAN.to_bits(),
// These two masks cover all the mantissa bits. One of them is a signalling NaN, the
// other is quiet.
// Similar to the masks in `test_float_bits_conv` in library/std/src/f64/tests.rs
f64::NAN.to_bits() ^ 0x000A_AAAA_AAAA_AAAA,
f64::NAN.to_bits() ^ 0x0005_5555_5555_5555,
// Same as above but with the sign bit flipped.
f64::NAN.to_bits() ^ 0x800A_AAAA_AAAA_AAAA,
f64::NAN.to_bits() ^ 0x8005_5555_5555_5555,
]);
for bits in bits_f64 {
assert_eq!(identity(f64::from_bits(bits)).to_bits(), bits);
// Test types that are returned as scalar pairs.
assert_eq!(identity((f64::from_bits(bits), 42)).0.to_bits(), bits);
assert_eq!(identity((42, f64::from_bits(bits))).1.to_bits(), bits);
let (a, b) = identity((f64::from_bits(bits), f64::from_bits(bits)));
assert_eq!((a.to_bits(), b.to_bits()), (bits, bits));
}
}
}
#[inline(never)]
fn identity<T>(x: T) -> T {
x
}
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