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Make overflowing and wrapping negation const

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Remember that the signed and unsigned versions are slightly different here, so there's four functions made const instead of just two.
This commit is contained in:
Lokathor 2019-02-01 01:31:52 -07:00
parent 741a3d42cb
commit 2f5d2455a4
1 changed files with 5 additions and 9 deletions
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14
src/libcore/num/mod.rs
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@ -1175,7 +1175,7 @@ $EndFeature, "
```"),
#[stable(feature = "num_wrapping", since = "1.2.0")]
#[inline]
pub fn wrapping_neg(self) -> Self {
pub const fn wrapping_neg(self) -> Self {
self.overflowing_neg().0
}
}
@ -1529,12 +1529,8 @@ assert_eq!(", stringify!($SelfT), "::MIN.overflowing_neg(), (", stringify!($Self
```"),
#[inline]
#[stable(feature = "wrapping", since = "1.7.0")]
pub fn overflowing_neg(self) -> (Self, bool) {
if self == Self::min_value() {
(Self::min_value(), true)
} else {
(-self, false)
}
pub const fn overflowing_neg(self) -> (Self, bool) {
((self ^ -1).wrapping_add(1), s == $SelfT::min_value())
}
}
@ -3017,7 +3013,7 @@ assert_eq!(100", stringify!($SelfT), ".wrapping_rem_euclid(10), 0);
/// ```
#[stable(feature = "num_wrapping", since = "1.2.0")]
#[inline]
pub fn wrapping_neg(self) -> Self {
pub const fn wrapping_neg(self) -> Self {
self.overflowing_neg().0
}
@ -3322,7 +3318,7 @@ assert_eq!(2", stringify!($SelfT), ".overflowing_neg(), (-2i32 as ", stringify!(
```"),
#[inline]
#[stable(feature = "wrapping", since = "1.7.0")]
pub fn overflowing_neg(self) -> (Self, bool) {
pub const fn overflowing_neg(self) -> (Self, bool) {
((!self).wrapping_add(1), self != 0)
}
}