1 use core::f32;
2 
3 /// Ceil (f32)
4 ///
5 /// Finds the nearest integer greater than or equal to `x`.
6 #[cfg_attr(all(test, assert_no_panic), no_panic::no_panic)]
ceilf(x: f32) -> f327 pub fn ceilf(x: f32) -> f32 {
8     // On wasm32 we know that LLVM's intrinsic will compile to an optimized
9     // `f32.ceil` native instruction, so we can leverage this for both code size
10     // and speed.
11     llvm_intrinsically_optimized! {
12         #[cfg(target_arch = "wasm32")] {
13             return unsafe { ::core::intrinsics::ceilf32(x) }
14         }
15     }
16     let mut ui = x.to_bits();
17     let e = (((ui >> 23) & 0xff).wrapping_sub(0x7f)) as i32;
18 
19     if e >= 23 {
20         return x;
21     }
22     if e >= 0 {
23         let m = 0x007fffff >> e;
24         if (ui & m) == 0 {
25             return x;
26         }
27         force_eval!(x + f32::from_bits(0x7b800000));
28         if ui >> 31 == 0 {
29             ui += m;
30         }
31         ui &= !m;
32     } else {
33         force_eval!(x + f32::from_bits(0x7b800000));
34         if ui >> 31 != 0 {
35             return -0.0;
36         } else if ui << 1 != 0 {
37             return 1.0;
38         }
39     }
40     f32::from_bits(ui)
41 }
42 
43 // PowerPC tests are failing on LLVM 13: https://github.com/rust-lang/rust/issues/88520
44 #[cfg(not(target_arch = "powerpc64"))]
45 #[cfg(test)]
46 mod tests {
47     use super::*;
48     use core::f32::*;
49 
50     #[test]
sanity_check()51     fn sanity_check() {
52         assert_eq!(ceilf(1.1), 2.0);
53         assert_eq!(ceilf(2.9), 3.0);
54     }
55 
56     /// The spec: https://en.cppreference.com/w/cpp/numeric/math/ceil
57     #[test]
spec_tests()58     fn spec_tests() {
59         // Not Asserted: that the current rounding mode has no effect.
60         assert!(ceilf(NAN).is_nan());
61         for f in [0.0, -0.0, INFINITY, NEG_INFINITY].iter().copied() {
62             assert_eq!(ceilf(f), f);
63         }
64     }
65 }
66