src/test/run-pass/saturating-float-casts.rs

   1 // Copyright 2017 The Rust Project Developers. See the COPYRIGHT
   2 // file at the top-level directory of this distribution and at
   3 // http://rust-lang.org/COPYRIGHT.
   4 //
   5 // Licensed under the Apache License, Version 2.0 <LICENSE-APACHE or
   6 // http://www.apache.org/licenses/LICENSE-2.0> or the MIT license
   7 // <LICENSE-MIT or http://opensource.org/licenses/MIT>, at your
   8 // option. This file may not be copied, modified, or distributed
   9 // except according to those terms.
  10
  11 // Tests saturating float->int casts. See u128-as-f32.rs for the opposite direction.
  12 // compile-flags: -Z saturating-float-casts
  13
  14 #![feature(test, i128, i128_type, stmt_expr_attributes)]
  15 #![deny(overflowing_literals)]
  16 extern crate test;
  17
  18 use std::{f32, f64};
  19 use std::{u8, i8, u16, i16, u32, i32, u64, i64};
  20 #[cfg(not(target_os="emscripten"))]
  21 use std::{u128, i128};
  22 use test::black_box;
  23
  24 macro_rules! test {
  25     ($val:expr, $src_ty:ident -> $dest_ty:ident, $expected:expr) => (
  26         // black_box disables constant evaluation to test run-time conversions:
  27         assert_eq!(black_box::<$src_ty>($val) as $dest_ty, $expected,
  28                     "run-time {} -> {}", stringify!($src_ty), stringify!($dest_ty));
  29     );
  30
  31     ($fval:expr, f* -> $ity:ident, $ival:expr) => (
  32         test!($fval, f32 -> $ity, $ival);
  33         test!($fval, f64 -> $ity, $ival);
  34     )
  35 }
  36
  37 // This macro tests const eval in addition to run-time evaluation.
  38 // If and when saturating casts are adopted, this macro should be merged with test!() to ensure
  39 // that run-time and const eval agree on inputs that currently trigger a const eval error.
  40 macro_rules! test_c {
  41     ($val:expr, $src_ty:ident -> $dest_ty:ident, $expected:expr) => ({
  42         test!($val, $src_ty -> $dest_ty, $expected);
  43         {
  44             const X: $src_ty = $val;
  45             const Y: $dest_ty = X as $dest_ty;
  46             assert_eq!(Y, $expected,
  47                         "const eval {} -> {}", stringify!($src_ty), stringify!($dest_ty));
  48         }
  49     });
  50
  51     ($fval:expr, f* -> $ity:ident, $ival:expr) => (
  52         test_c!($fval, f32 -> $ity, $ival);
  53         test_c!($fval, f64 -> $ity, $ival);
  54     )
  55 }
  56
  57 macro_rules! common_fptoi_tests {
  58     ($fty:ident -> $($ity:ident)+) => ({ $(
  59         test!($fty::NAN, $fty -> $ity, 0);
  60         test!($fty::INFINITY, $fty -> $ity, $ity::MAX);
  61         test!($fty::NEG_INFINITY, $fty -> $ity, $ity::MIN);
  62         // These two tests are not solely float->int tests, in particular the latter relies on
  63         // `u128::MAX as f32` not being UB. But that's okay, since this file tests int->float
  64         // as well, the test is just slightly misplaced.
  65         test!($ity::MIN as $fty, $fty -> $ity, $ity::MIN);
  66         test!($ity::MAX as $fty, $fty -> $ity, $ity::MAX);
  67         test_c!(0., $fty -> $ity, 0);
  68         test_c!($fty::MIN_POSITIVE, $fty -> $ity, 0);
  69         test!(-0.9, $fty -> $ity, 0);
  70         test_c!(1., $fty -> $ity, 1);
  71         test_c!(42., $fty -> $ity, 42);
  72     )+ });
  73
  74     (f* -> $($ity:ident)+) => ({
  75         common_fptoi_tests!(f32 -> $($ity)+);
  76         common_fptoi_tests!(f64 -> $($ity)+);
  77     })
  78 }
  79
  80 macro_rules! fptoui_tests {
  81     ($fty: ident -> $($ity: ident)+) => ({ $(
  82         test!(-0., $fty -> $ity, 0);
  83         test!(-$fty::MIN_POSITIVE, $fty -> $ity, 0);
  84         test!(-0.99999994, $fty -> $ity, 0);
  85         test!(-1., $fty -> $ity, 0);
  86         test!(-100., $fty -> $ity, 0);
  87         test!(#[allow(overflowing_literals)] -1e50, $fty -> $ity, 0);
  88         test!(#[allow(overflowing_literals)] -1e130, $fty -> $ity, 0);
  89     )+ });
  90
  91     (f* -> $($ity:ident)+) => ({
  92         fptoui_tests!(f32 -> $($ity)+);
  93         fptoui_tests!(f64 -> $($ity)+);
  94     })
  95 }
  96
  97 pub fn main() {
  98     common_fptoi_tests!(f* -> i8 i16 i32 i64 u8 u16 u32 u64);
  99     fptoui_tests!(f* -> u8 u16 u32 u64);
 100     // FIXME emscripten does not support i128
 101     #[cfg(not(target_os="emscripten"))] {
 102         common_fptoi_tests!(f* -> i128 u128);
 103         fptoui_tests!(f* -> u128);
 104     }
 105
 106     // The following tests cover edge cases for some integer types.
 107
 108     // # u8
 109     test_c!(254., f* -> u8, 254);
 110     test!(256., f* -> u8, 255);
 111
 112     // # i8
 113     test_c!(-127., f* -> i8, -127);
 114     test!(-129., f* -> i8, -128);
 115     test_c!(126., f* -> i8, 126);
 116     test!(128., f* -> i8, 127);
 117
 118     // # i32
 119     // -2147483648. is i32::MIN (exactly)
 120     test_c!(-2147483648., f* -> i32, i32::MIN);
 121     // 2147483648. is i32::MAX rounded up
 122     test!(2147483648., f32 -> i32, 2147483647);
 123     // With 24 significand bits, floats with magnitude in [2^30 + 1, 2^31] are rounded to
 124     // multiples of 2^7. Therefore, nextDown(round(i32::MAX)) is 2^31 - 128:
 125     test_c!(2147483520., f32 -> i32, 2147483520);
 126     // Similarly, nextUp(i32::MIN) is i32::MIN + 2^8 and nextDown(i32::MIN) is i32::MIN - 2^7
 127     test!(-2147483904., f* -> i32, i32::MIN);
 128     test_c!(-2147483520., f* -> i32, -2147483520);
 129
 130     // # u32
 131     // round(MAX) and nextUp(round(MAX))
 132     test_c!(4294967040., f* -> u32, 4294967040);
 133     test!(4294967296., f* -> u32, 4294967295);
 134
 135     // # u128
 136     #[cfg(not(target_os="emscripten"))]
 137     {
 138         // float->int:
 139         test_c!(f32::MAX, f32 -> u128, 0xffffff00000000000000000000000000);
 140         // nextDown(f32::MAX) = 2^128 - 2 * 2^104
 141         const SECOND_LARGEST_F32: f32 = 340282326356119256160033759537265639424.;
 142         test_c!(SECOND_LARGEST_F32, f32 -> u128, 0xfffffe00000000000000000000000000);
 143     }
 144 }