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47 lines
2.0 KiB
Rust
47 lines
2.0 KiB
Rust
// run-pass
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#![feature(test)]
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#![deny(overflowing_literals)]
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extern crate test;
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use test::black_box;
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macro_rules! test {
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($val:expr, $src_ty:ident -> $dest_ty:ident, $expected:expr) => ({
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{
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const X: $src_ty = $val;
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const Y: $dest_ty = X as $dest_ty;
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assert_eq!(Y, $expected,
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"const eval {} -> {}", stringify!($src_ty), stringify!($dest_ty));
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}
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// black_box disables constant evaluation to test run-time conversions:
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assert_eq!(black_box::<$src_ty>($val) as $dest_ty, $expected,
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"run-time {} -> {}", stringify!($src_ty), stringify!($dest_ty));
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});
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}
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pub fn main() {
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// nextDown(f32::MAX) = 2^128 - 2 * 2^104
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const SECOND_LARGEST_F32: f32 = 340282326356119256160033759537265639424.;
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// f32::MAX - 0.5 ULP and smaller should be rounded down
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test!(0xfffffe00000000000000000000000000, u128 -> f32, SECOND_LARGEST_F32);
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test!(0xfffffe7fffffffffffffffffffffffff, u128 -> f32, SECOND_LARGEST_F32);
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test!(0xfffffe80000000000000000000000000, u128 -> f32, SECOND_LARGEST_F32);
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// numbers within < 0.5 ULP of f32::MAX it should be rounded to f32::MAX
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test!(0xfffffe80000000000000000000000001, u128 -> f32, f32::MAX);
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test!(0xfffffeffffffffffffffffffffffffff, u128 -> f32, f32::MAX);
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test!(0xffffff00000000000000000000000000, u128 -> f32, f32::MAX);
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test!(0xffffff00000000000000000000000001, u128 -> f32, f32::MAX);
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test!(0xffffff7fffffffffffffffffffffffff, u128 -> f32, f32::MAX);
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// f32::MAX + 0.5 ULP and greater should be rounded to infinity
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test!(0xffffff80000000000000000000000000, u128 -> f32, f32::INFINITY);
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test!(0xffffff80000000f00000000000000000, u128 -> f32, f32::INFINITY);
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test!(0xffffff87ffffffffffffffff00000001, u128 -> f32, f32::INFINITY);
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// u128->f64 should not be affected by the u128->f32 checks
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test!(0xffffff80000000000000000000000000, u128 -> f64,
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340282356779733661637539395458142568448.0);
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test!(u128::MAX, u128 -> f64, 340282366920938463463374607431768211455.0);
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}
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