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Make integer power methods const

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This commit is contained in:
Dylan MacKenzie 2020-02-08 16:32:30 -08:00
parent 2afa99379d
commit 269bf89865
2 changed files with 31 additions and 14 deletions
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3
src/libcore/lib.rs
View file

@ -72,11 +72,14 @@
#![feature(concat_idents)]
#![feature(const_alloc_layout)]
#![feature(const_if_match)]
#![feature(const_loop)]
#![feature(const_checked_int_methods)]
#![feature(const_euclidean_int_methods)]
#![feature(const_overflowing_int_methods)]
#![feature(const_saturating_int_methods)]
#![feature(const_int_unchecked_arith)]
#![feature(const_int_pow)]
#![feature(constctlz)]
#![feature(const_panic)]
#![feature(const_fn_union)]
#![feature(const_generics)]

42
src/libcore/num/mod.rs
View file

@ -1001,10 +1001,11 @@ $EndFeature, "
```"),
#[stable(feature = "no_panic_pow", since = "1.34.0")]
#[rustc_const_unstable(feature = "const_int_pow", issue = "53718")]
#[must_use = "this returns the result of the operation, \
without modifying the original"]
#[inline]
pub fn checked_pow(self, mut exp: u32) -> Option<Self> {
pub const fn checked_pow(self, mut exp: u32) -> Option<Self> {
let mut base = self;
let mut acc: Self = 1;
@ -1188,10 +1189,11 @@ assert_eq!(", stringify!($SelfT), "::MIN.saturating_pow(3), ", stringify!($SelfT
$EndFeature, "
```"),
#[stable(feature = "no_panic_pow", since = "1.34.0")]
#[rustc_const_unstable(feature = "const_int_pow", issue = "53718")]
#[must_use = "this returns the result of the operation, \
without modifying the original"]
#[inline]
pub fn saturating_pow(self, exp: u32) -> Self {
pub const fn saturating_pow(self, exp: u32) -> Self {
match self.checked_pow(exp) {
Some(x) => x,
None if self < 0 && exp % 2 == 1 => Self::min_value(),
@ -1531,10 +1533,11 @@ assert_eq!(3i8.wrapping_pow(6), -39);",
$EndFeature, "
```"),
#[stable(feature = "no_panic_pow", since = "1.34.0")]
#[rustc_const_unstable(feature = "const_int_pow", issue = "53718")]
#[must_use = "this returns the result of the operation, \
without modifying the original"]
#[inline]
pub fn wrapping_pow(self, mut exp: u32) -> Self {
pub const fn wrapping_pow(self, mut exp: u32) -> Self {
let mut base = self;
let mut acc: Self = 1;
@ -1908,10 +1911,11 @@ assert_eq!(3i8.overflowing_pow(5), (-13, true));",
$EndFeature, "
```"),
#[stable(feature = "no_panic_pow", since = "1.34.0")]
#[rustc_const_unstable(feature = "const_int_pow", issue = "53718")]
#[must_use = "this returns the result of the operation, \
without modifying the original"]
#[inline]
pub fn overflowing_pow(self, mut exp: u32) -> (Self, bool) {
pub const fn overflowing_pow(self, mut exp: u32) -> (Self, bool) {
let mut base = self;
let mut acc: Self = 1;
let mut overflown = false;
@ -1957,11 +1961,12 @@ assert_eq!(x.pow(5), 32);",
$EndFeature, "
```"),
#[stable(feature = "rust1", since = "1.0.0")]
#[rustc_const_unstable(feature = "const_int_pow", issue = "53718")]
#[must_use = "this returns the result of the operation, \
without modifying the original"]
#[inline]
#[rustc_inherit_overflow_checks]
pub fn pow(self, mut exp: u32) -> Self {
pub const fn pow(self, mut exp: u32) -> Self {
let mut base = self;
let mut acc = 1;
@ -3127,10 +3132,11 @@ Basic usage:
assert_eq!(", stringify!($SelfT), "::max_value().checked_pow(2), None);", $EndFeature, "
```"),
#[stable(feature = "no_panic_pow", since = "1.34.0")]
#[rustc_const_unstable(feature = "const_int_pow", issue = "53718")]
#[must_use = "this returns the result of the operation, \
without modifying the original"]
#[inline]
pub fn checked_pow(self, mut exp: u32) -> Option<Self> {
pub const fn checked_pow(self, mut exp: u32) -> Option<Self> {
let mut base = self;
let mut acc: Self = 1;
@ -3242,10 +3248,11 @@ assert_eq!(", stringify!($SelfT), "::MAX.saturating_pow(2), ", stringify!($SelfT
$EndFeature, "
```"),
#[stable(feature = "no_panic_pow", since = "1.34.0")]
#[rustc_const_unstable(feature = "const_int_pow", issue = "53718")]
#[must_use = "this returns the result of the operation, \
without modifying the original"]
#[inline]
pub fn saturating_pow(self, exp: u32) -> Self {
pub const fn saturating_pow(self, exp: u32) -> Self {
match self.checked_pow(exp) {
Some(x) => x,
None => Self::max_value(),
@ -3535,10 +3542,11 @@ Basic usage:
assert_eq!(3u8.wrapping_pow(6), 217);", $EndFeature, "
```"),
#[stable(feature = "no_panic_pow", since = "1.34.0")]
#[rustc_const_unstable(feature = "const_int_pow", issue = "53718")]
#[must_use = "this returns the result of the operation, \
without modifying the original"]
#[inline]
pub fn wrapping_pow(self, mut exp: u32) -> Self {
pub const fn wrapping_pow(self, mut exp: u32) -> Self {
let mut base = self;
let mut acc: Self = 1;
@ -3861,10 +3869,11 @@ Basic usage:
assert_eq!(3u8.overflowing_pow(6), (217, true));", $EndFeature, "
```"),
#[stable(feature = "no_panic_pow", since = "1.34.0")]
#[rustc_const_unstable(feature = "const_int_pow", issue = "53718")]
#[must_use = "this returns the result of the operation, \
without modifying the original"]
#[inline]
pub fn overflowing_pow(self, mut exp: u32) -> (Self, bool) {
pub const fn overflowing_pow(self, mut exp: u32) -> (Self, bool) {
let mut base = self;
let mut acc: Self = 1;
let mut overflown = false;
@ -3907,11 +3916,12 @@ Basic usage:
", $Feature, "assert_eq!(2", stringify!($SelfT), ".pow(5), 32);", $EndFeature, "
```"),
#[stable(feature = "rust1", since = "1.0.0")]
#[rustc_const_unstable(feature = "const_int_pow", issue = "53718")]
#[must_use = "this returns the result of the operation, \
without modifying the original"]
#[inline]
#[rustc_inherit_overflow_checks]
pub fn pow(self, mut exp: u32) -> Self {
pub const fn pow(self, mut exp: u32) -> Self {
let mut base = self;
let mut acc = 1;
@ -4022,7 +4032,8 @@ assert!(!10", stringify!($SelfT), ".is_power_of_two());", $EndFeature, "
// overflow cases it instead ends up returning the maximum value
// of the type, and can return 0 for 0.
#[inline]
fn one_less_than_next_power_of_two(self) -> Self {
#[rustc_const_unstable(feature = "const_int_pow", issue = "53718")]
const fn one_less_than_next_power_of_two(self) -> Self {
if self <= 1 { return 0; }
let p = self - 1;
@ -4050,9 +4061,10 @@ Basic usage:
assert_eq!(3", stringify!($SelfT), ".next_power_of_two(), 4);", $EndFeature, "
```"),
#[stable(feature = "rust1", since = "1.0.0")]
#[rustc_const_unstable(feature = "const_int_pow", issue = "53718")]
#[inline]
#[rustc_inherit_overflow_checks]
pub fn next_power_of_two(self) -> Self {
pub const fn next_power_of_two(self) -> Self {
self.one_less_than_next_power_of_two() + 1
}
}
@ -4075,7 +4087,8 @@ $EndFeature, "
```"),
#[inline]
#[stable(feature = "rust1", since = "1.0.0")]
pub fn checked_next_power_of_two(self) -> Option<Self> {
#[rustc_const_unstable(feature = "const_int_pow", issue = "53718")]
pub const fn checked_next_power_of_two(self) -> Option<Self> {
self.one_less_than_next_power_of_two().checked_add(1)
}
}
@ -4099,7 +4112,8 @@ $EndFeature, "
```"),
#[unstable(feature = "wrapping_next_power_of_two", issue = "32463",
reason = "needs decision on wrapping behaviour")]
pub fn wrapping_next_power_of_two(self) -> Self {
#[rustc_const_unstable(feature = "const_int_pow", issue = "53718")]
pub const fn wrapping_next_power_of_two(self) -> Self {
self.one_less_than_next_power_of_two().wrapping_add(1)
}
}