#![feature(stmt_expr_attributes, bench_black_box)] #![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(x: T, y: T) { assert_eq!(x, y); } trait FloatToInt: Copy { fn cast(self) -> Int; unsafe fn cast_unchecked(self) -> Int; } impl FloatToInt for f32 { fn cast(self) -> i8 { self as _ } unsafe fn cast_unchecked(self) -> i8 { self.to_int_unchecked() } } impl FloatToInt for f32 { fn cast(self) -> i32 { self as _ } unsafe fn cast_unchecked(self) -> i32 { self.to_int_unchecked() } } impl FloatToInt for f32 { fn cast(self) -> u32 { self as _ } unsafe fn cast_unchecked(self) -> u32 { self.to_int_unchecked() } } impl FloatToInt for f32 { fn cast(self) -> i64 { self as _ } unsafe fn cast_unchecked(self) -> i64 { self.to_int_unchecked() } } impl FloatToInt for f32 { fn cast(self) -> u64 { self as _ } unsafe fn cast_unchecked(self) -> u64 { self.to_int_unchecked() } } impl FloatToInt for f64 { fn cast(self) -> i8 { self as _ } unsafe fn cast_unchecked(self) -> i8 { self.to_int_unchecked() } } impl FloatToInt for f64 { fn cast(self) -> i32 { self as _ } unsafe fn cast_unchecked(self) -> i32 { self.to_int_unchecked() } } impl FloatToInt for f64 { fn cast(self) -> u32 { self as _ } unsafe fn cast_unchecked(self) -> u32 { self.to_int_unchecked() } } impl FloatToInt for f64 { fn cast(self) -> i64 { self as _ } unsafe fn cast_unchecked(self) -> i64 { self.to_int_unchecked() } } impl FloatToInt for f64 { fn cast(self) -> u64 { self as _ } unsafe fn cast_unchecked(self) -> u64 { self.to_int_unchecked() } } impl FloatToInt for f64 { fn cast(self) -> i128 { self as _ } unsafe fn cast_unchecked(self) -> i128 { self.to_int_unchecked() } } impl FloatToInt 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(x: F, y: I) where F: FloatToInt, 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::(127.99, 127); test_both_cast::(-128.99, -128); // f32 -> i32 test_both_cast::(0.0, 0); test_both_cast::(-0.0, 0); test_both_cast::(/*0x1p-149*/ f32::from_bits(0x00000001), 0); test_both_cast::(/*-0x1p-149*/ f32::from_bits(0x80000001), 0); test_both_cast::(/*0x1.19999ap+0*/ f32::from_bits(0x3f8ccccd), 1); test_both_cast::(/*-0x1.19999ap+0*/ f32::from_bits(0xbf8ccccd), -1); test_both_cast::(1.9, 1); test_both_cast::(-1.9, -1); test_both_cast::(5.0, 5); test_both_cast::(-5.0, -5); test_both_cast::(2147483520.0, 2147483520); test_both_cast::(-2147483648.0, -2147483648); // unrepresentable casts assert_eq::(2147483648.0f32 as i32, i32::MAX); assert_eq::(-2147483904.0f32 as i32, i32::MIN); assert_eq::(f32::MAX as i32, i32::MAX); assert_eq::(f32::MIN as i32, i32::MIN); assert_eq::(f32::INFINITY as i32, i32::MAX); assert_eq::(f32::NEG_INFINITY as i32, i32::MIN); assert_eq::(f32::NAN as i32, 0); assert_eq::((-f32::NAN) as i32, 0); // f32 -> u32 test_both_cast::(0.0, 0); test_both_cast::(-0.0, 0); test_both_cast::(-0.9999999, 0); test_both_cast::(/*0x1p-149*/ f32::from_bits(0x1), 0); test_both_cast::(/*-0x1p-149*/ f32::from_bits(0x80000001), 0); test_both_cast::(/*0x1.19999ap+0*/ f32::from_bits(0x3f8ccccd), 1); test_both_cast::(1.9, 1); test_both_cast::(5.0, 5); test_both_cast::(2147483648.0, 0x8000_0000); test_both_cast::(4294967040.0, 0u32.wrapping_sub(256)); test_both_cast::(/*-0x1.ccccccp-1*/ f32::from_bits(0xbf666666), 0); test_both_cast::(/*-0x1.fffffep-1*/ f32::from_bits(0xbf7fffff), 0); test_both_cast::((u32::MAX-128) as f32, u32::MAX-255); // rounding loss // unrepresentable casts assert_eq::((u32::MAX-127) as f32 as u32, u32::MAX); // rounds up and then becomes unrepresentable assert_eq::(4294967296.0f32 as u32, u32::MAX); assert_eq::(-5.0f32 as u32, 0); assert_eq::(f32::MAX as u32, u32::MAX); assert_eq::(f32::MIN as u32, 0); assert_eq::(f32::INFINITY as u32, u32::MAX); assert_eq::(f32::NEG_INFINITY as u32, 0); assert_eq::(f32::NAN as u32, 0); assert_eq::((-f32::NAN) as u32, 0); // f32 -> i64 test_both_cast::(4294967296.0, 4294967296); test_both_cast::(-4294967296.0, -4294967296); test_both_cast::(9223371487098961920.0, 9223371487098961920); test_both_cast::(-9223372036854775808.0, -9223372036854775808); // f64 -> i8 test_both_cast::(127.99, 127); test_both_cast::(-128.99, -128); // f64 -> i32 test_both_cast::(0.0, 0); test_both_cast::(-0.0, 0); test_both_cast::(/*0x1.199999999999ap+0*/ f64::from_bits(0x3ff199999999999a), 1); test_both_cast::(/*-0x1.199999999999ap+0*/ f64::from_bits(0xbff199999999999a), -1); test_both_cast::(1.9, 1); test_both_cast::(-1.9, -1); test_both_cast::(1e8, 100_000_000); test_both_cast::(2147483647.0, 2147483647); test_both_cast::(-2147483648.0, -2147483648); // unrepresentable casts assert_eq::(2147483648.0f64 as i32, i32::MAX); assert_eq::(-2147483649.0f64 as i32, i32::MIN); // f64 -> i64 test_both_cast::(0.0, 0); test_both_cast::(-0.0, 0); test_both_cast::(/*0x0.0000000000001p-1022*/ f64::from_bits(0x1), 0); test_both_cast::(/*-0x0.0000000000001p-1022*/ f64::from_bits(0x8000000000000001), 0); test_both_cast::(/*0x1.199999999999ap+0*/ f64::from_bits(0x3ff199999999999a), 1); test_both_cast::(/*-0x1.199999999999ap+0*/ f64::from_bits(0xbff199999999999a), -1); test_both_cast::(5.0, 5); test_both_cast::(5.9, 5); test_both_cast::(-5.0, -5); test_both_cast::(-5.9, -5); test_both_cast::(4294967296.0, 4294967296); test_both_cast::(-4294967296.0, -4294967296); test_both_cast::(9223372036854774784.0, 9223372036854774784); test_both_cast::(-9223372036854775808.0, -9223372036854775808); // unrepresentable casts assert_eq::(9223372036854775808.0f64 as i64, i64::MAX); assert_eq::(-9223372036854777856.0f64 as i64, i64::MIN); assert_eq::(f64::MAX as i64, i64::MAX); assert_eq::(f64::MIN as i64, i64::MIN); assert_eq::(f64::INFINITY as i64, i64::MAX); assert_eq::(f64::NEG_INFINITY as i64, i64::MIN); assert_eq::(f64::NAN as i64, 0); assert_eq::((-f64::NAN) as i64, 0); // f64 -> u64 test_both_cast::(0.0, 0); test_both_cast::(-0.0, 0); test_both_cast::(-0.99999999999, 0); test_both_cast::(5.0, 5); test_both_cast::(1e16, 10000000000000000); test_both_cast::((u64::MAX-1024) as f64, u64::MAX-2047); // rounding loss test_both_cast::(9223372036854775808.0, 9223372036854775808); // unrepresentable casts assert_eq::(-5.0f64 as u64, 0); assert_eq::((u64::MAX-1023) as f64 as u64, u64::MAX); // rounds up and then becomes unrepresentable assert_eq::(18446744073709551616.0f64 as u64, u64::MAX); assert_eq::(f64::MAX as u64, u64::MAX); assert_eq::(f64::MIN as u64, 0); assert_eq::(f64::INFINITY as u64, u64::MAX); assert_eq::(f64::NEG_INFINITY as u64, 0); assert_eq::(f64::NAN as u64, 0); assert_eq::((-f64::NAN) as u64, 0); // f64 -> i128 assert_eq::(f64::MAX as i128, i128::MAX); assert_eq::(f64::MIN as i128, i128::MIN); // f64 -> u128 assert_eq::(f64::MAX as u128, u128::MAX); assert_eq::(f64::MIN as u128, 0); // int -> f32 assert_eq::(127i8 as f32, 127.0); assert_eq::(2147483647i32 as f32, 2147483648.0); assert_eq::((-2147483648i32) as f32, -2147483648.0); assert_eq::(1234567890i32 as f32, /*0x1.26580cp+30*/ f32::from_bits(0x4e932c06)); assert_eq::(16777217i32 as f32, 16777216.0); assert_eq::((-16777217i32) as f32, -16777216.0); assert_eq::(16777219i32 as f32, 16777220.0); assert_eq::((-16777219i32) as f32, -16777220.0); assert_eq::(0x7fffff4000000001i64 as f32, /*0x1.fffffep+62*/ f32::from_bits(0x5effffff)); assert_eq::(0x8000004000000001u64 as i64 as f32, /*-0x1.fffffep+62*/ f32::from_bits(0xdeffffff)); assert_eq::(0x0020000020000001i64 as f32, /*0x1.000002p+53*/ f32::from_bits(0x5a000001)); assert_eq::(0xffdfffffdfffffffu64 as i64 as f32, /*-0x1.000002p+53*/ f32::from_bits(0xda000001)); assert_eq::(i128::MIN as f32, -170141183460469231731687303715884105728.0f32); assert_eq::(u128::MAX as f32, f32::INFINITY); // saturation // int -> f64 assert_eq::(127i8 as f64, 127.0); assert_eq::(i16::MIN as f64, -32768.0f64); assert_eq::(2147483647i32 as f64, 2147483647.0); assert_eq::(-2147483648i32 as f64, -2147483648.0); assert_eq::(987654321i32 as f64, 987654321.0); assert_eq::(9223372036854775807i64 as f64, 9223372036854775807.0); assert_eq::(-9223372036854775808i64 as f64, -9223372036854775808.0); assert_eq::(4669201609102990i64 as f64, 4669201609102990.0); // Feigenbaum (?) assert_eq::(9007199254740993i64 as f64, 9007199254740992.0); assert_eq::(-9007199254740993i64 as f64, -9007199254740992.0); assert_eq::(9007199254740995i64 as f64, 9007199254740996.0); assert_eq::(-9007199254740995i64 as f64, -9007199254740996.0); assert_eq::(u128::MAX as f64, 340282366920938463463374607431768211455.0f64); // even that fits... // f32 -> f64 assert_eq::((0.0f32 as f64).to_bits(), 0.0f64.to_bits()); assert_eq::(((-0.0f32) as f64).to_bits(), (-0.0f64).to_bits()); assert_eq::(5.0f32 as f64, 5.0f64); assert_eq::(/*0x1p-149*/ f32::from_bits(0x1) as f64, /*0x1p-149*/ f64::from_bits(0x36a0000000000000)); assert_eq::(/*-0x1p-149*/ f32::from_bits(0x80000001) as f64, /*-0x1p-149*/ f64::from_bits(0xb6a0000000000000)); assert_eq::(/*0x1.fffffep+127*/ f32::from_bits(0x7f7fffff) as f64, /*0x1.fffffep+127*/ f64::from_bits(0x47efffffe0000000)); assert_eq::(/*-0x1.fffffep+127*/ (-f32::from_bits(0x7f7fffff)) as f64, /*-0x1.fffffep+127*/ -f64::from_bits(0x47efffffe0000000)); assert_eq::(/*0x1p-119*/ f32::from_bits(0x4000000) as f64, /*0x1p-119*/ f64::from_bits(0x3880000000000000)); assert_eq::(/*0x1.8f867ep+125*/ f32::from_bits(0x7e47c33f) as f64, 6.6382536710104395e+37); assert_eq::(f32::INFINITY as f64, f64::INFINITY); assert_eq::(f32::NEG_INFINITY as f64, f64::NEG_INFINITY); // f64 -> f32 assert_eq::((0.0f64 as f32).to_bits(), 0.0f32.to_bits()); assert_eq::(((-0.0f64) as f32).to_bits(), (-0.0f32).to_bits()); assert_eq::(5.0f64 as f32, 5.0f32); assert_eq::(/*0x0.0000000000001p-1022*/ f64::from_bits(0x1) as f32, 0.0); assert_eq::(/*-0x0.0000000000001p-1022*/ (-f64::from_bits(0x1)) as f32, -0.0); assert_eq::(/*0x1.fffffe0000000p-127*/ f64::from_bits(0x380fffffe0000000) as f32, /*0x1p-149*/ f32::from_bits(0x800000)); assert_eq::(/*0x1.4eae4f7024c7p+108*/ f64::from_bits(0x46b4eae4f7024c70) as f32, /*0x1.4eae5p+108*/ f32::from_bits(0x75a75728)); assert_eq::(f64::MAX as f32, f32::INFINITY); assert_eq::(f64::MIN as f32, f32::NEG_INFINITY); assert_eq::(f64::INFINITY as f32, f32::INFINITY); assert_eq::(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()); }