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float.rs
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#![feature(stmt_expr_attributes)]
#![allow(arithmetic_overflow)]
use std::fmt::Debug;
use std::hint::black_box;
fn main() {
basic();
casts();
more_casts();
ops();
nan_casts();
}
// Helper function to avoid promotion so that this tests "run-time" casts, not CTFE.
// Doesn't make a big difference when running this in Miri, but it means we can compare this
// with the LLVM backend by running `rustc -Zmir-opt-level=0 -Zsaturating-float-casts`.
#[track_caller]
#[inline(never)]
fn assert_eq<T: PartialEq + Debug>(x: T, y: T) {
assert_eq!(x, y);
}
trait FloatToInt<Int>: Copy {
fn cast(self) -> Int;
unsafe fn cast_unchecked(self) -> Int;
}
impl FloatToInt<i8> for f32 {
fn cast(self) -> i8 {
self as _
}
unsafe fn cast_unchecked(self) -> i8 {
self.to_int_unchecked()
}
}
impl FloatToInt<i32> for f32 {
fn cast(self) -> i32 {
self as _
}
unsafe fn cast_unchecked(self) -> i32 {
self.to_int_unchecked()
}
}
impl FloatToInt<u32> for f32 {
fn cast(self) -> u32 {
self as _
}
unsafe fn cast_unchecked(self) -> u32 {
self.to_int_unchecked()
}
}
impl FloatToInt<i64> for f32 {
fn cast(self) -> i64 {
self as _
}
unsafe fn cast_unchecked(self) -> i64 {
self.to_int_unchecked()
}
}
impl FloatToInt<u64> for f32 {
fn cast(self) -> u64 {
self as _
}
unsafe fn cast_unchecked(self) -> u64 {
self.to_int_unchecked()
}
}
impl FloatToInt<i8> for f64 {
fn cast(self) -> i8 {
self as _
}
unsafe fn cast_unchecked(self) -> i8 {
self.to_int_unchecked()
}
}
impl FloatToInt<i32> for f64 {
fn cast(self) -> i32 {
self as _
}
unsafe fn cast_unchecked(self) -> i32 {
self.to_int_unchecked()
}
}
impl FloatToInt<u32> for f64 {
fn cast(self) -> u32 {
self as _
}
unsafe fn cast_unchecked(self) -> u32 {
self.to_int_unchecked()
}
}
impl FloatToInt<i64> for f64 {
fn cast(self) -> i64 {
self as _
}
unsafe fn cast_unchecked(self) -> i64 {
self.to_int_unchecked()
}
}
impl FloatToInt<u64> for f64 {
fn cast(self) -> u64 {
self as _
}
unsafe fn cast_unchecked(self) -> u64 {
self.to_int_unchecked()
}
}
impl FloatToInt<i128> for f64 {
fn cast(self) -> i128 {
self as _
}
unsafe fn cast_unchecked(self) -> i128 {
self.to_int_unchecked()
}
}
impl FloatToInt<u128> for f64 {
fn cast(self) -> u128 {
self as _
}
unsafe fn cast_unchecked(self) -> u128 {
self.to_int_unchecked()
}
}
/// Test this cast both via `as` and via `approx_unchecked` (i.e., it must not saturate).
#[track_caller]
#[inline(never)]
fn test_both_cast<F, I>(x: F, y: I)
where
F: FloatToInt<I>,
I: PartialEq + Debug,
{
assert_eq!(x.cast(), y);
assert_eq!(unsafe { x.cast_unchecked() }, y);
}
fn basic() {
// basic arithmetic
assert_eq(6.0_f32 * 6.0_f32, 36.0_f32);
assert_eq(6.0_f64 * 6.0_f64, 36.0_f64);
assert_eq(-{ 5.0_f32 }, -5.0_f32);
assert_eq(-{ 5.0_f64 }, -5.0_f64);
// infinities, NaN
assert!((5.0_f32 / 0.0).is_infinite());
assert_ne!({ 5.0_f32 / 0.0 }, { -5.0_f32 / 0.0 });
assert!((5.0_f64 / 0.0).is_infinite());
assert_ne!({ 5.0_f64 / 0.0 }, { 5.0_f64 / -0.0 });
assert!((-5.0_f32).sqrt().is_nan());
assert!((-5.0_f64).sqrt().is_nan());
assert_ne!(f32::NAN, f32::NAN);
assert_ne!(f64::NAN, f64::NAN);
// negative zero
let posz = 0.0f32;
let negz = -0.0f32;
assert_eq(posz, negz);
assert_ne!(posz.to_bits(), negz.to_bits());
let posz = 0.0f64;
let negz = -0.0f64;
assert_eq(posz, negz);
assert_ne!(posz.to_bits(), negz.to_bits());
// byte-level transmute
let x: u64 = unsafe { std::mem::transmute(42.0_f64) };
let y: f64 = unsafe { std::mem::transmute(x) };
assert_eq(y, 42.0_f64);
let x: u32 = unsafe { std::mem::transmute(42.0_f32) };
let y: f32 = unsafe { std::mem::transmute(x) };
assert_eq(y, 42.0_f32);
}
/// Many of these test values are taken from
/// https://github.com/WebAssembly/testsuite/blob/master/conversions.wast.
fn casts() {
// f32 -> i8
test_both_cast::<f32, i8>(127.99, 127);
test_both_cast::<f32, i8>(-128.99, -128);
// f32 -> i32
test_both_cast::<f32, i32>(0.0, 0);
test_both_cast::<f32, i32>(-0.0, 0);
test_both_cast::<f32, i32>(/*0x1p-149*/ f32::from_bits(0x00000001), 0);
test_both_cast::<f32, i32>(/*-0x1p-149*/ f32::from_bits(0x80000001), 0);
test_both_cast::<f32, i32>(/*0x1.19999ap+0*/ f32::from_bits(0x3f8ccccd), 1);
test_both_cast::<f32, i32>(/*-0x1.19999ap+0*/ f32::from_bits(0xbf8ccccd), -1);
test_both_cast::<f32, i32>(1.9, 1);
test_both_cast::<f32, i32>(-1.9, -1);
test_both_cast::<f32, i32>(5.0, 5);
test_both_cast::<f32, i32>(-5.0, -5);
test_both_cast::<f32, i32>(2147483520.0, 2147483520);
test_both_cast::<f32, i32>(-2147483648.0, -2147483648);
// unrepresentable casts
assert_eq::<i32>(2147483648.0f32 as i32, i32::MAX);
assert_eq::<i32>(-2147483904.0f32 as i32, i32::MIN);
assert_eq::<i32>(f32::MAX as i32, i32::MAX);
assert_eq::<i32>(f32::MIN as i32, i32::MIN);
assert_eq::<i32>(f32::INFINITY as i32, i32::MAX);
assert_eq::<i32>(f32::NEG_INFINITY as i32, i32::MIN);
assert_eq::<i32>(f32::NAN as i32, 0);
assert_eq::<i32>((-f32::NAN) as i32, 0);
// f32 -> u32
test_both_cast::<f32, u32>(0.0, 0);
test_both_cast::<f32, u32>(-0.0, 0);
test_both_cast::<f32, u32>(-0.9999999, 0);
test_both_cast::<f32, u32>(/*0x1p-149*/ f32::from_bits(0x1), 0);
test_both_cast::<f32, u32>(/*-0x1p-149*/ f32::from_bits(0x80000001), 0);
test_both_cast::<f32, u32>(/*0x1.19999ap+0*/ f32::from_bits(0x3f8ccccd), 1);
test_both_cast::<f32, u32>(1.9, 1);
test_both_cast::<f32, u32>(5.0, 5);
test_both_cast::<f32, u32>(2147483648.0, 0x8000_0000);
test_both_cast::<f32, u32>(4294967040.0, 0u32.wrapping_sub(256));
test_both_cast::<f32, u32>(/*-0x1.ccccccp-1*/ f32::from_bits(0xbf666666), 0);
test_both_cast::<f32, u32>(/*-0x1.fffffep-1*/ f32::from_bits(0xbf7fffff), 0);
test_both_cast::<f32, u32>((u32::MAX - 128) as f32, u32::MAX - 255); // rounding loss
// unrepresentable casts
assert_eq::<u32>((u32::MAX - 127) as f32 as u32, u32::MAX); // rounds up and then becomes unrepresentable
assert_eq::<u32>(4294967296.0f32 as u32, u32::MAX);
assert_eq::<u32>(-5.0f32 as u32, 0);
assert_eq::<u32>(f32::MAX as u32, u32::MAX);
assert_eq::<u32>(f32::MIN as u32, 0);
assert_eq::<u32>(f32::INFINITY as u32, u32::MAX);
assert_eq::<u32>(f32::NEG_INFINITY as u32, 0);
assert_eq::<u32>(f32::NAN as u32, 0);
assert_eq::<u32>((-f32::NAN) as u32, 0);
// f32 -> i64
test_both_cast::<f32, i64>(4294967296.0, 4294967296);
test_both_cast::<f32, i64>(-4294967296.0, -4294967296);
test_both_cast::<f32, i64>(9223371487098961920.0, 9223371487098961920);
test_both_cast::<f32, i64>(-9223372036854775808.0, -9223372036854775808);
// f64 -> i8
test_both_cast::<f64, i8>(127.99, 127);
test_both_cast::<f64, i8>(-128.99, -128);
// f64 -> i32
test_both_cast::<f64, i32>(0.0, 0);
test_both_cast::<f64, i32>(-0.0, 0);
test_both_cast::<f64, i32>(/*0x1.199999999999ap+0*/ f64::from_bits(0x3ff199999999999a), 1);
test_both_cast::<f64, i32>(
/*-0x1.199999999999ap+0*/ f64::from_bits(0xbff199999999999a),
-1,
);
test_both_cast::<f64, i32>(1.9, 1);
test_both_cast::<f64, i32>(-1.9, -1);
test_both_cast::<f64, i32>(1e8, 100_000_000);
test_both_cast::<f64, i32>(2147483647.0, 2147483647);
test_both_cast::<f64, i32>(-2147483648.0, -2147483648);
// unrepresentable casts
assert_eq::<i32>(2147483648.0f64 as i32, i32::MAX);
assert_eq::<i32>(-2147483649.0f64 as i32, i32::MIN);
// f64 -> i64
test_both_cast::<f64, i64>(0.0, 0);
test_both_cast::<f64, i64>(-0.0, 0);
test_both_cast::<f64, i64>(/*0x0.0000000000001p-1022*/ f64::from_bits(0x1), 0);
test_both_cast::<f64, i64>(
/*-0x0.0000000000001p-1022*/ f64::from_bits(0x8000000000000001),
0,
);
test_both_cast::<f64, i64>(/*0x1.199999999999ap+0*/ f64::from_bits(0x3ff199999999999a), 1);
test_both_cast::<f64, i64>(
/*-0x1.199999999999ap+0*/ f64::from_bits(0xbff199999999999a),
-1,
);
test_both_cast::<f64, i64>(5.0, 5);
test_both_cast::<f64, i64>(5.9, 5);
test_both_cast::<f64, i64>(-5.0, -5);
test_both_cast::<f64, i64>(-5.9, -5);
test_both_cast::<f64, i64>(4294967296.0, 4294967296);
test_both_cast::<f64, i64>(-4294967296.0, -4294967296);
test_both_cast::<f64, i64>(9223372036854774784.0, 9223372036854774784);
test_both_cast::<f64, i64>(-9223372036854775808.0, -9223372036854775808);
// unrepresentable casts
assert_eq::<i64>(9223372036854775808.0f64 as i64, i64::MAX);
assert_eq::<i64>(-9223372036854777856.0f64 as i64, i64::MIN);
assert_eq::<i64>(f64::MAX as i64, i64::MAX);
assert_eq::<i64>(f64::MIN as i64, i64::MIN);
assert_eq::<i64>(f64::INFINITY as i64, i64::MAX);
assert_eq::<i64>(f64::NEG_INFINITY as i64, i64::MIN);
assert_eq::<i64>(f64::NAN as i64, 0);
assert_eq::<i64>((-f64::NAN) as i64, 0);
// f64 -> u64
test_both_cast::<f64, u64>(0.0, 0);
test_both_cast::<f64, u64>(-0.0, 0);
test_both_cast::<f64, u64>(-0.99999999999, 0);
test_both_cast::<f64, u64>(5.0, 5);
test_both_cast::<f64, u64>(1e16, 10000000000000000);
test_both_cast::<f64, u64>((u64::MAX - 1024) as f64, u64::MAX - 2047); // rounding loss
test_both_cast::<f64, u64>(9223372036854775808.0, 9223372036854775808);
// unrepresentable casts
assert_eq::<u64>(-5.0f64 as u64, 0);
assert_eq::<u64>((u64::MAX - 1023) as f64 as u64, u64::MAX); // rounds up and then becomes unrepresentable
assert_eq::<u64>(18446744073709551616.0f64 as u64, u64::MAX);
assert_eq::<u64>(f64::MAX as u64, u64::MAX);
assert_eq::<u64>(f64::MIN as u64, 0);
assert_eq::<u64>(f64::INFINITY as u64, u64::MAX);
assert_eq::<u64>(f64::NEG_INFINITY as u64, 0);
assert_eq::<u64>(f64::NAN as u64, 0);
assert_eq::<u64>((-f64::NAN) as u64, 0);
// f64 -> i128
assert_eq::<i128>(f64::MAX as i128, i128::MAX);
assert_eq::<i128>(f64::MIN as i128, i128::MIN);
// f64 -> u128
assert_eq::<u128>(f64::MAX as u128, u128::MAX);
assert_eq::<u128>(f64::MIN as u128, 0);
// int -> f32
assert_eq::<f32>(127i8 as f32, 127.0);
assert_eq::<f32>(2147483647i32 as f32, 2147483648.0);
assert_eq::<f32>((-2147483648i32) as f32, -2147483648.0);
assert_eq::<f32>(1234567890i32 as f32, /*0x1.26580cp+30*/ f32::from_bits(0x4e932c06));
assert_eq::<f32>(16777217i32 as f32, 16777216.0);
assert_eq::<f32>((-16777217i32) as f32, -16777216.0);
assert_eq::<f32>(16777219i32 as f32, 16777220.0);
assert_eq::<f32>((-16777219i32) as f32, -16777220.0);
assert_eq::<f32>(
0x7fffff4000000001i64 as f32,
/*0x1.fffffep+62*/ f32::from_bits(0x5effffff),
);
assert_eq::<f32>(
0x8000004000000001u64 as i64 as f32,
/*-0x1.fffffep+62*/ f32::from_bits(0xdeffffff),
);
assert_eq::<f32>(
0x0020000020000001i64 as f32,
/*0x1.000002p+53*/ f32::from_bits(0x5a000001),
);
assert_eq::<f32>(
0xffdfffffdfffffffu64 as i64 as f32,
/*-0x1.000002p+53*/ f32::from_bits(0xda000001),
);
assert_eq::<f32>(i128::MIN as f32, -170141183460469231731687303715884105728.0f32);
assert_eq::<f32>(u128::MAX as f32, f32::INFINITY); // saturation
// int -> f64
assert_eq::<f64>(127i8 as f64, 127.0);
assert_eq::<f64>(i16::MIN as f64, -32768.0f64);
assert_eq::<f64>(2147483647i32 as f64, 2147483647.0);
assert_eq::<f64>(-2147483648i32 as f64, -2147483648.0);
assert_eq::<f64>(987654321i32 as f64, 987654321.0);
assert_eq::<f64>(9223372036854775807i64 as f64, 9223372036854775807.0);
assert_eq::<f64>(-9223372036854775808i64 as f64, -9223372036854775808.0);
assert_eq::<f64>(4669201609102990i64 as f64, 4669201609102990.0); // Feigenbaum (?)
assert_eq::<f64>(9007199254740993i64 as f64, 9007199254740992.0);
assert_eq::<f64>(-9007199254740993i64 as f64, -9007199254740992.0);
assert_eq::<f64>(9007199254740995i64 as f64, 9007199254740996.0);
assert_eq::<f64>(-9007199254740995i64 as f64, -9007199254740996.0);
assert_eq::<f64>(u128::MAX as f64, 340282366920938463463374607431768211455.0f64); // even that fits...
// f32 -> f64
assert_eq::<u64>((0.0f32 as f64).to_bits(), 0.0f64.to_bits());
assert_eq::<u64>(((-0.0f32) as f64).to_bits(), (-0.0f64).to_bits());
assert_eq::<f64>(5.0f32 as f64, 5.0f64);
assert_eq::<f64>(
/*0x1p-149*/ f32::from_bits(0x1) as f64,
/*0x1p-149*/ f64::from_bits(0x36a0000000000000),
);
assert_eq::<f64>(
/*-0x1p-149*/ f32::from_bits(0x80000001) as f64,
/*-0x1p-149*/ f64::from_bits(0xb6a0000000000000),
);
assert_eq::<f64>(
/*0x1.fffffep+127*/ f32::from_bits(0x7f7fffff) as f64,
/*0x1.fffffep+127*/ f64::from_bits(0x47efffffe0000000),
);
assert_eq::<f64>(
/*-0x1.fffffep+127*/ (-f32::from_bits(0x7f7fffff)) as f64,
/*-0x1.fffffep+127*/ -f64::from_bits(0x47efffffe0000000),
);
assert_eq::<f64>(
/*0x1p-119*/ f32::from_bits(0x4000000) as f64,
/*0x1p-119*/ f64::from_bits(0x3880000000000000),
);
assert_eq::<f64>(
/*0x1.8f867ep+125*/ f32::from_bits(0x7e47c33f) as f64,
6.6382536710104395e+37,
);
assert_eq::<f64>(f32::INFINITY as f64, f64::INFINITY);
assert_eq::<f64>(f32::NEG_INFINITY as f64, f64::NEG_INFINITY);
// f64 -> f32
assert_eq::<u32>((0.0f64 as f32).to_bits(), 0.0f32.to_bits());
assert_eq::<u32>(((-0.0f64) as f32).to_bits(), (-0.0f32).to_bits());
assert_eq::<f32>(5.0f64 as f32, 5.0f32);
assert_eq::<f32>(/*0x0.0000000000001p-1022*/ f64::from_bits(0x1) as f32, 0.0);
assert_eq::<f32>(/*-0x0.0000000000001p-1022*/ (-f64::from_bits(0x1)) as f32, -0.0);
assert_eq::<f32>(
/*0x1.fffffe0000000p-127*/ f64::from_bits(0x380fffffe0000000) as f32,
/*0x1p-149*/ f32::from_bits(0x800000),
);
assert_eq::<f32>(
/*0x1.4eae4f7024c7p+108*/ f64::from_bits(0x46b4eae4f7024c70) as f32,
/*0x1.4eae5p+108*/ f32::from_bits(0x75a75728),
);
assert_eq::<f32>(f64::MAX as f32, f32::INFINITY);
assert_eq::<f32>(f64::MIN as f32, f32::NEG_INFINITY);
assert_eq::<f32>(f64::INFINITY as f32, f32::INFINITY);
assert_eq::<f32>(f64::NEG_INFINITY as f32, f32::NEG_INFINITY);
}
fn ops() {
// f32 min/max
assert_eq((1.0 as f32).max(-1.0), 1.0);
assert_eq((1.0 as f32).min(-1.0), -1.0);
assert_eq(f32::NAN.min(9.0), 9.0);
assert_eq(f32::NAN.max(-9.0), -9.0);
assert_eq((9.0 as f32).min(f32::NAN), 9.0);
assert_eq((-9.0 as f32).max(f32::NAN), -9.0);
// f64 min/max
assert_eq((1.0 as f64).max(-1.0), 1.0);
assert_eq((1.0 as f64).min(-1.0), -1.0);
assert_eq(f64::NAN.min(9.0), 9.0);
assert_eq(f64::NAN.max(-9.0), -9.0);
assert_eq((9.0 as f64).min(f64::NAN), 9.0);
assert_eq((-9.0 as f64).max(f64::NAN), -9.0);
// f32 copysign
assert_eq(3.5_f32.copysign(0.42), 3.5_f32);
assert_eq(3.5_f32.copysign(-0.42), -3.5_f32);
assert_eq((-3.5_f32).copysign(0.42), 3.5_f32);
assert_eq((-3.5_f32).copysign(-0.42), -3.5_f32);
assert!(f32::NAN.copysign(1.0).is_nan());
// f64 copysign
assert_eq(3.5_f64.copysign(0.42), 3.5_f64);
assert_eq(3.5_f64.copysign(-0.42), -3.5_f64);
assert_eq((-3.5_f64).copysign(0.42), 3.5_f64);
assert_eq((-3.5_f64).copysign(-0.42), -3.5_f64);
assert!(f64::NAN.copysign(1.0).is_nan());
}
/// Tests taken from rustc test suite.
///
macro_rules! test {
($val:expr, $src_ty:ident -> $dest_ty:ident, $expected:expr) => (
// black_box disables constant evaluation to test run-time conversions:
assert_eq!(black_box::<$src_ty>($val) as $dest_ty, $expected,
"run-time {} -> {}", stringify!($src_ty), stringify!($dest_ty));
{
const X: $src_ty = $val;
const Y: $dest_ty = X as $dest_ty;
assert_eq!(Y, $expected,
"const eval {} -> {}", stringify!($src_ty), stringify!($dest_ty));
}
);
($fval:expr, f* -> $ity:ident, $ival:expr) => (
test!($fval, f32 -> $ity, $ival);
test!($fval, f64 -> $ity, $ival);
)
}
macro_rules! common_fptoi_tests {
($fty:ident -> $($ity:ident)+) => ({ $(
test!($fty::NAN, $fty -> $ity, 0);
test!($fty::INFINITY, $fty -> $ity, $ity::MAX);
test!($fty::NEG_INFINITY, $fty -> $ity, $ity::MIN);
// These two tests are not solely float->int tests, in particular the latter relies on
// `u128::MAX as f32` not being UB. But that's okay, since this file tests int->float
// as well, the test is just slightly misplaced.
test!($ity::MIN as $fty, $fty -> $ity, $ity::MIN);
test!($ity::MAX as $fty, $fty -> $ity, $ity::MAX);
test!(0., $fty -> $ity, 0);
test!($fty::MIN_POSITIVE, $fty -> $ity, 0);
test!(-0.9, $fty -> $ity, 0);
test!(1., $fty -> $ity, 1);
test!(42., $fty -> $ity, 42);
)+ });
(f* -> $($ity:ident)+) => ({
common_fptoi_tests!(f32 -> $($ity)+);
common_fptoi_tests!(f64 -> $($ity)+);
})
}
macro_rules! fptoui_tests {
($fty: ident -> $($ity: ident)+) => ({ $(
test!(-0., $fty -> $ity, 0);
test!(-$fty::MIN_POSITIVE, $fty -> $ity, 0);
test!(-0.99999994, $fty -> $ity, 0);
test!(-1., $fty -> $ity, 0);
test!(-100., $fty -> $ity, 0);
test!(#[allow(overflowing_literals)] -1e50, $fty -> $ity, 0);
test!(#[allow(overflowing_literals)] -1e130, $fty -> $ity, 0);
)+ });
(f* -> $($ity:ident)+) => ({
fptoui_tests!(f32 -> $($ity)+);
fptoui_tests!(f64 -> $($ity)+);
})
}
fn more_casts() {
common_fptoi_tests!(f* -> i8 i16 i32 i64 u8 u16 u32 u64);
fptoui_tests!(f* -> u8 u16 u32 u64);
common_fptoi_tests!(f* -> i128 u128);
fptoui_tests!(f* -> u128);
// The following tests cover edge cases for some integer types.
// # u8
test!(254., f* -> u8, 254);
test!(256., f* -> u8, 255);
// # i8
test!(-127., f* -> i8, -127);
test!(-129., f* -> i8, -128);
test!(126., f* -> i8, 126);
test!(128., f* -> i8, 127);
// # i32
// -2147483648. is i32::MIN (exactly)
test!(-2147483648., f* -> i32, i32::MIN);
// 2147483648. is i32::MAX rounded up
test!(2147483648., f32 -> i32, 2147483647);
// With 24 significand bits, floats with magnitude in [2^30 + 1, 2^31] are rounded to
// multiples of 2^7. Therefore, nextDown(round(i32::MAX)) is 2^31 - 128:
test!(2147483520., f32 -> i32, 2147483520);
// Similarly, nextUp(i32::MIN) is i32::MIN + 2^8 and nextDown(i32::MIN) is i32::MIN - 2^7
test!(-2147483904., f* -> i32, i32::MIN);
test!(-2147483520., f* -> i32, -2147483520);
// # u32
// round(MAX) and nextUp(round(MAX))
test!(4294967040., f* -> u32, 4294967040);
test!(4294967296., f* -> u32, 4294967295);
// # u128
// float->int:
test!(f32::MAX, f32 -> u128, 0xffffff00000000000000000000000000);
// nextDown(f32::MAX) = 2^128 - 2 * 2^104
const SECOND_LARGEST_F32: f32 = 340282326356119256160033759537265639424.;
test!(SECOND_LARGEST_F32, f32 -> u128, 0xfffffe00000000000000000000000000);
}
fn nan_casts() {
let nan1 = f64::from_bits(0x7FF0_0001_0000_0001u64);
let nan2 = f64::from_bits(0x7FF0_0000_0000_0001u64);
assert!(nan1.is_nan());
assert!(nan2.is_nan());
let nan1_32 = nan1 as f32;
let nan2_32 = nan2 as f32;
assert!(nan1_32.is_nan());
assert!(nan2_32.is_nan());
}