Skip to content

Commit

Permalink
Rollup merge of #73938 - nbdd0121:checked_opt, r=nagisa
Browse files Browse the repository at this point in the history 
Optimise fast path of checked_ops with `unlikely`

This PR marks paths returning `None` in checked_ops as unlikely to improvde codegen.

Fixes #73731
  • Loading branch information
@Manishearth
Manishearth authored Jul 2, 2020
2 parents 061f1c6 + 86d8644 commit 4f536f2
Showing 1 changed file with 43 additions and 27 deletions.
70 changes: 43 additions & 27 deletions src/libcore/num/mod.rs
View file
Original file line number Diff line number Diff line change
Expand Up @@ -21,6 +21,21 @@ macro_rules! try_opt {
};
}

#[cfg(bootstrap)]
macro_rules! unlikely {
($e: expr) => {
$e
};
}

#[cfg(not(bootstrap))]
#[allow_internal_unstable(const_likely)]
macro_rules! unlikely {
($e: expr) => {
intrinsics::unlikely($e)
};
}

macro_rules! impl_nonzero_fmt {
( #[$stability: meta] ( $( $Trait: ident ),+ ) for $Ty: ident ) => {
$(
Expand Down Expand Up @@ -746,7 +761,7 @@ $EndFeature, "
#[inline]
pub const fn checked_add(self, rhs: Self) -> Option<Self> {
let (a, b) = self.overflowing_add(rhs);
if b {None} else {Some(a)}
if unlikely!(b) {None} else {Some(a)}
}
}

Expand Down Expand Up @@ -790,7 +805,7 @@ $EndFeature, "
#[inline]
pub const fn checked_sub(self, rhs: Self) -> Option<Self> {
let (a, b) = self.overflowing_sub(rhs);
if b {None} else {Some(a)}
if unlikely!(b) {None} else {Some(a)}
}
}

Expand Down Expand Up @@ -834,7 +849,7 @@ $EndFeature, "
#[inline]
pub const fn checked_mul(self, rhs: Self) -> Option<Self> {
let (a, b) = self.overflowing_mul(rhs);
if b {None} else {Some(a)}
if unlikely!(b) {None} else {Some(a)}
}
}

Expand Down Expand Up @@ -878,7 +893,7 @@ $EndFeature, "
without modifying the original"]
#[inline]
pub const fn checked_div(self, rhs: Self) -> Option<Self> {
if rhs == 0 || (self == Self::MIN && rhs == -1) {
if unlikely!(rhs == 0 || (self == Self::MIN && rhs == -1)) {
None
} else {
// SAFETY: div by zero and by INT_MIN have been checked above
Expand Down Expand Up @@ -907,7 +922,7 @@ assert_eq!((1", stringify!($SelfT), ").checked_div_euclid(0), None);
without modifying the original"]
#[inline]
pub const fn checked_div_euclid(self, rhs: Self) -> Option<Self> {
if rhs == 0 || (self == Self::MIN && rhs == -1) {
if unlikely!(rhs == 0 || (self == Self::MIN && rhs == -1)) {
None
} else {
Some(self.div_euclid(rhs))
Expand Down Expand Up @@ -936,7 +951,7 @@ $EndFeature, "
without modifying the original"]
#[inline]
pub const fn checked_rem(self, rhs: Self) -> Option<Self> {
if rhs == 0 || (self == Self::MIN && rhs == -1) {
if unlikely!(rhs == 0 || (self == Self::MIN && rhs == -1)) {
None
} else {
// SAFETY: div by zero and by INT_MIN have been checked above
Expand Down Expand Up @@ -964,7 +979,7 @@ assert_eq!(", stringify!($SelfT), "::MIN.checked_rem_euclid(-1), None);
without modifying the original"]
#[inline]
pub const fn checked_rem_euclid(self, rhs: Self) -> Option<Self> {
if rhs == 0 || (self == Self::MIN && rhs == -1) {
if unlikely!(rhs == 0 || (self == Self::MIN && rhs == -1)) {
None
} else {
Some(self.rem_euclid(rhs))
Expand All @@ -990,7 +1005,7 @@ $EndFeature, "
#[inline]
pub const fn checked_neg(self) -> Option<Self> {
let (a, b) = self.overflowing_neg();
if b {None} else {Some(a)}
if unlikely!(b) {None} else {Some(a)}
}
}

Expand All @@ -1014,7 +1029,7 @@ $EndFeature, "
#[inline]
pub const fn checked_shl(self, rhs: u32) -> Option<Self> {
let (a, b) = self.overflowing_shl(rhs);
if b {None} else {Some(a)}
if unlikely!(b) {None} else {Some(a)}
}
}

Expand All @@ -1038,7 +1053,7 @@ $EndFeature, "
#[inline]
pub const fn checked_shr(self, rhs: u32) -> Option<Self> {
let (a, b) = self.overflowing_shr(rhs);
if b {None} else {Some(a)}
if unlikely!(b) {None} else {Some(a)}
}
}

Expand Down Expand Up @@ -1745,7 +1760,7 @@ $EndFeature, "
#[must_use = "this returns the result of the operation, \
without modifying the original"]
pub const fn overflowing_div(self, rhs: Self) -> (Self, bool) {
if self == Self::MIN && rhs == -1 {
if unlikely!(self == Self::MIN && rhs == -1) {
(self, true)
} else {
(self / rhs, false)
Expand Down Expand Up @@ -1778,7 +1793,7 @@ assert_eq!(", stringify!($SelfT), "::MIN.overflowing_div_euclid(-1), (", stringi
#[must_use = "this returns the result of the operation, \
without modifying the original"]
pub const fn overflowing_div_euclid(self, rhs: Self) -> (Self, bool) {
if self == Self::MIN && rhs == -1 {
if unlikely!(self == Self::MIN && rhs == -1) {
(self, true)
} else {
(self.div_euclid(rhs), false)
Expand Down Expand Up @@ -1812,7 +1827,7 @@ $EndFeature, "
#[must_use = "this returns the result of the operation, \
without modifying the original"]
pub const fn overflowing_rem(self, rhs: Self) -> (Self, bool) {
if self == Self::MIN && rhs == -1 {
if unlikely!(self == Self::MIN && rhs == -1) {
(0, true)
} else {
(self % rhs, false)
Expand Down Expand Up @@ -1845,7 +1860,7 @@ assert_eq!(", stringify!($SelfT), "::MIN.overflowing_rem_euclid(-1), (0, true));
without modifying the original"]
#[inline]
pub const fn overflowing_rem_euclid(self, rhs: Self) -> (Self, bool) {
if self == Self::MIN && rhs == -1 {
if unlikely!(self == Self::MIN && rhs == -1) {
(0, true)
} else {
(self.rem_euclid(rhs), false)
Expand Down Expand Up @@ -1876,7 +1891,7 @@ assert_eq!(", stringify!($SelfT), "::MIN.overflowing_neg(), (", stringify!($Self
#[allow(unused_attributes)]
#[cfg_attr(bootstrap, allow_internal_unstable(const_if_match))]
pub const fn overflowing_neg(self) -> (Self, bool) {
if self == Self::MIN {
if unlikely!(self == Self::MIN) {
(Self::MIN, true)
} else {
(-self, false)
Expand Down Expand Up @@ -2988,7 +3003,7 @@ assert_eq!((", stringify!($SelfT), "::MAX - 2).checked_add(3), None);", $EndFeat
#[inline]
pub const fn checked_add(self, rhs: Self) -> Option<Self> {
let (a, b) = self.overflowing_add(rhs);
if b {None} else {Some(a)}
if unlikely!(b) {None} else {Some(a)}
}
}

Expand Down Expand Up @@ -3030,7 +3045,7 @@ assert_eq!(0", stringify!($SelfT), ".checked_sub(1), None);", $EndFeature, "
#[inline]
pub const fn checked_sub(self, rhs: Self) -> Option<Self> {
let (a, b) = self.overflowing_sub(rhs);
if b {None} else {Some(a)}
if unlikely!(b) {None} else {Some(a)}
}
}

Expand Down Expand Up @@ -3072,7 +3087,7 @@ assert_eq!(", stringify!($SelfT), "::MAX.checked_mul(2), None);", $EndFeature, "
#[inline]
pub const fn checked_mul(self, rhs: Self) -> Option<Self> {
let (a, b) = self.overflowing_mul(rhs);
if b {None} else {Some(a)}
if unlikely!(b) {None} else {Some(a)}
}
}

Expand Down Expand Up @@ -3113,11 +3128,12 @@ assert_eq!(1", stringify!($SelfT), ".checked_div(0), None);", $EndFeature, "
without modifying the original"]
#[inline]
pub const fn checked_div(self, rhs: Self) -> Option<Self> {
match rhs {
0 => None,
if unlikely!(rhs == 0) {
None
} else {
// SAFETY: div by zero has been checked above and unsigned types have no other
// failure modes for division
rhs => Some(unsafe { intrinsics::unchecked_div(self, rhs) }),
Some(unsafe { intrinsics::unchecked_div(self, rhs) })
}
}
}
Expand All @@ -3140,7 +3156,7 @@ assert_eq!(1", stringify!($SelfT), ".checked_div_euclid(0), None);
without modifying the original"]
#[inline]
pub const fn checked_div_euclid(self, rhs: Self) -> Option<Self> {
if rhs == 0 {
if unlikely!(rhs == 0) {
None
} else {
Some(self.div_euclid(rhs))
Expand All @@ -3167,7 +3183,7 @@ assert_eq!(5", stringify!($SelfT), ".checked_rem(0), None);", $EndFeature, "
without modifying the original"]
#[inline]
pub const fn checked_rem(self, rhs: Self) -> Option<Self> {
if rhs == 0 {
if unlikely!(rhs == 0) {
None
} else {
// SAFETY: div by zero has been checked above and unsigned types have no other
Expand Down Expand Up @@ -3195,7 +3211,7 @@ assert_eq!(5", stringify!($SelfT), ".checked_rem_euclid(0), None);
without modifying the original"]
#[inline]
pub const fn checked_rem_euclid(self, rhs: Self) -> Option<Self> {
if rhs == 0 {
if unlikely!(rhs == 0) {
None
} else {
Some(self.rem_euclid(rhs))
Expand All @@ -3222,7 +3238,7 @@ assert_eq!(1", stringify!($SelfT), ".checked_neg(), None);", $EndFeature, "
#[inline]
pub const fn checked_neg(self) -> Option<Self> {
let (a, b) = self.overflowing_neg();
if b {None} else {Some(a)}
if unlikely!(b) {None} else {Some(a)}
}
}

Expand All @@ -3245,7 +3261,7 @@ assert_eq!(0x10", stringify!($SelfT), ".checked_shl(129), None);", $EndFeature,
#[inline]
pub const fn checked_shl(self, rhs: u32) -> Option<Self> {
let (a, b) = self.overflowing_shl(rhs);
if b {None} else {Some(a)}
if unlikely!(b) {None} else {Some(a)}
}
}

Expand All @@ -3268,7 +3284,7 @@ assert_eq!(0x10", stringify!($SelfT), ".checked_shr(129), None);", $EndFeature,
#[inline]
pub const fn checked_shr(self, rhs: u32) -> Option<Self> {
let (a, b) = self.overflowing_shr(rhs);
if b {None} else {Some(a)}
if unlikely!(b) {None} else {Some(a)}
}
}

Expand Down

0 comments on commit 4f536f2

Please sign in to comment.