diff options
| -rw-r--r-- | library/core/src/num/int_macros.rs | 11 |
1 files changed, 6 insertions, 5 deletions
diff --git a/library/core/src/num/int_macros.rs b/library/core/src/num/int_macros.rs index 21518a3f551..ba89553f65a 100644 --- a/library/core/src/num/int_macros.rs +++ b/library/core/src/num/int_macros.rs @@ -2574,12 +2574,13 @@ macro_rules! int_impl { #[must_use = "this returns the result of the operation, \ without modifying the original"] #[inline(always)] + #[rustc_allow_const_fn_unstable(const_cmp)] pub const fn signum(self) -> Self { - match self { - n if n > 0 => 1, - 0 => 0, - _ => -1, - } + // Picking the right way to phrase this is complicated + // (<https://graphics.stanford.edu/~seander/bithacks.html#CopyIntegerSign>) + // so delegate it to `Ord` which is already producing -1/0/+1 + // exactly like we need and can be the place to deal with the complexity. + self.cmp(&0) as _ } /// Returns `true` if `self` is positive and `false` if the number is zero or |