Auto merge of #126750 - scottmcm:less-unlikely, r=<try>

Stop using `unlikely` in `core::num` (Draft for now, will definitely need rebasing) r? ghost
rust-lang · Jun 20, 2024 · d44c1b9 · d44c1b9
2 parents 1ca578e + 776b56e
commit d44c1b9
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Showing 3 changed files with 42 additions and 49 deletions.
diff --git a/library/core/src/num/int_macros.rs b/library/core/src/num/int_macros.rs
@@ -449,7 +449,7 @@ macro_rules! int_impl {
         #[inline]
         pub const fn checked_add(self, rhs: Self) -> Option<Self> {
             let (a, b) = self.overflowing_add(rhs);
-            if unlikely!(b) { None } else { Some(a) }
+            if b { None } else { Some(a) }
         }
 
         /// Strict integer addition. Computes `self + rhs`, panicking
@@ -484,7 +484,7 @@ macro_rules! int_impl {
         #[track_caller]
         pub const fn strict_add(self, rhs: Self) -> Self {
             let (a, b) = self.overflowing_add(rhs);
-            if unlikely!(b) { overflow_panic::add() } else { a }
+            if b { overflow_panic::add() } else { a }
         }
 
         /// Unchecked integer addition. Computes `self + rhs`, assuming overflow
@@ -545,7 +545,7 @@ macro_rules! int_impl {
         #[inline]
         pub const fn checked_add_unsigned(self, rhs: $UnsignedT) -> Option<Self> {
             let (a, b) = self.overflowing_add_unsigned(rhs);
-            if unlikely!(b) { None } else { Some(a) }
+            if b { None } else { Some(a) }
         }
 
         /// Strict addition with an unsigned integer. Computes `self + rhs`,
@@ -580,7 +580,7 @@ macro_rules! int_impl {
         #[track_caller]
         pub const fn strict_add_unsigned(self, rhs: $UnsignedT) -> Self {
             let (a, b) = self.overflowing_add_unsigned(rhs);
-            if unlikely!(b) { overflow_panic::add() } else { a }
+            if b { overflow_panic::add() } else { a }
         }
 
         /// Checked integer subtraction. Computes `self - rhs`, returning `None` if
@@ -601,7 +601,7 @@ macro_rules! int_impl {
         #[inline]
         pub const fn checked_sub(self, rhs: Self) -> Option<Self> {
             let (a, b) = self.overflowing_sub(rhs);
-            if unlikely!(b) { None } else { Some(a) }
+            if b { None } else { Some(a) }
         }
 
         /// Strict integer subtraction. Computes `self - rhs`, panicking if
@@ -636,7 +636,7 @@ macro_rules! int_impl {
         #[track_caller]
         pub const fn strict_sub(self, rhs: Self) -> Self {
             let (a, b) = self.overflowing_sub(rhs);
-            if unlikely!(b) { overflow_panic::sub() } else { a }
+            if b { overflow_panic::sub() } else { a }
         }
 
         /// Unchecked integer subtraction. Computes `self - rhs`, assuming overflow
@@ -697,7 +697,7 @@ macro_rules! int_impl {
         #[inline]
         pub const fn checked_sub_unsigned(self, rhs: $UnsignedT) -> Option<Self> {
             let (a, b) = self.overflowing_sub_unsigned(rhs);
-            if unlikely!(b) { None } else { Some(a) }
+            if b { None } else { Some(a) }
         }
 
         /// Strict subtraction with an unsigned integer. Computes `self - rhs`,
@@ -732,7 +732,7 @@ macro_rules! int_impl {
         #[track_caller]
         pub const fn strict_sub_unsigned(self, rhs: $UnsignedT) -> Self {
             let (a, b) = self.overflowing_sub_unsigned(rhs);
-            if unlikely!(b) { overflow_panic::sub() } else { a }
+            if b { overflow_panic::sub() } else { a }
         }
 
         /// Checked integer multiplication. Computes `self * rhs`, returning `None` if
@@ -753,7 +753,7 @@ macro_rules! int_impl {
         #[inline]
         pub const fn checked_mul(self, rhs: Self) -> Option<Self> {
             let (a, b) = self.overflowing_mul(rhs);
-            if unlikely!(b) { None } else { Some(a) }
+            if b { None } else { Some(a) }
         }
 
         /// Strict integer multiplication. Computes `self * rhs`, panicking if
@@ -788,7 +788,7 @@ macro_rules! int_impl {
         #[track_caller]
         pub const fn strict_mul(self, rhs: Self) -> Self {
             let (a, b) = self.overflowing_mul(rhs);
-            if unlikely!(b) { overflow_panic::mul() } else { a }
+            if b { overflow_panic::mul() } else { a }
         }
 
         /// Unchecked integer multiplication. Computes `self * rhs`, assuming overflow
@@ -849,7 +849,7 @@ macro_rules! int_impl {
                       without modifying the original"]
         #[inline]
         pub const fn checked_div(self, rhs: Self) -> Option<Self> {
-            if unlikely!(rhs == 0 || ((self == Self::MIN) && (rhs == -1))) {
+            if rhs == 0 || ((self == Self::MIN) && (rhs == -1)) {
                 None
             } else {
                 // SAFETY: div by zero and by INT_MIN have been checked above
@@ -902,7 +902,7 @@ macro_rules! int_impl {
         #[track_caller]
         pub const fn strict_div(self, rhs: Self) -> Self {
             let (a, b) = self.overflowing_div(rhs);
-            if unlikely!(b) { overflow_panic::div() } else { a }
+            if b { overflow_panic::div() } else { a }
         }
 
         /// Checked Euclidean division. Computes `self.div_euclid(rhs)`,
@@ -924,7 +924,7 @@ macro_rules! int_impl {
         #[inline]
         pub const fn checked_div_euclid(self, rhs: Self) -> Option<Self> {
             // Using `&` helps LLVM see that it is the same check made in division.
-            if unlikely!(rhs == 0 || ((self == Self::MIN) & (rhs == -1))) {
+            if rhs == 0 || ((self == Self::MIN) & (rhs == -1)) {
                 None
             } else {
                 Some(self.div_euclid(rhs))
@@ -976,7 +976,7 @@ macro_rules! int_impl {
         #[track_caller]
         pub const fn strict_div_euclid(self, rhs: Self) -> Self {
             let (a, b) = self.overflowing_div_euclid(rhs);
-            if unlikely!(b) { overflow_panic::div() } else { a }
+            if b { overflow_panic::div() } else { a }
         }
 
         /// Checked integer remainder. Computes `self % rhs`, returning `None` if
@@ -997,7 +997,7 @@ macro_rules! int_impl {
                       without modifying the original"]
         #[inline]
         pub const fn checked_rem(self, rhs: Self) -> Option<Self> {
-            if unlikely!(rhs == 0 || ((self == Self::MIN) && (rhs == -1))) {
+            if rhs == 0 || ((self == Self::MIN) && (rhs == -1)) {
                 None
             } else {
                 // SAFETY: div by zero and by INT_MIN have been checked above
@@ -1049,7 +1049,7 @@ macro_rules! int_impl {
         #[track_caller]
         pub const fn strict_rem(self, rhs: Self) -> Self {
             let (a, b) = self.overflowing_rem(rhs);
-            if unlikely!(b) { overflow_panic::rem() } else { a }
+            if b { overflow_panic::rem() } else { a }
         }
 
         /// Checked Euclidean remainder. Computes `self.rem_euclid(rhs)`, returning `None`
@@ -1071,7 +1071,7 @@ macro_rules! int_impl {
         #[inline]
         pub const fn checked_rem_euclid(self, rhs: Self) -> Option<Self> {
             // Using `&` helps LLVM see that it is the same check made in division.
-            if unlikely!(rhs == 0 || ((self == Self::MIN) & (rhs == -1))) {
+            if rhs == 0 || ((self == Self::MIN) & (rhs == -1)) {
                 None
             } else {
                 Some(self.rem_euclid(rhs))
@@ -1122,7 +1122,7 @@ macro_rules! int_impl {
         #[track_caller]
         pub const fn strict_rem_euclid(self, rhs: Self) -> Self {
             let (a, b) = self.overflowing_rem_euclid(rhs);
-            if unlikely!(b) { overflow_panic::rem() } else { a }
+            if b { overflow_panic::rem() } else { a }
         }
 
         /// Checked negation. Computes `-self`, returning `None` if `self == MIN`.
@@ -1142,7 +1142,7 @@ macro_rules! int_impl {
         #[inline]
         pub const fn checked_neg(self) -> Option<Self> {
             let (a, b) = self.overflowing_neg();
-            if unlikely!(b) { None } else { Some(a) }
+            if b { None } else { Some(a) }
         }
 
         /// Unchecked negation. Computes `-self`, assuming overflow cannot occur.
@@ -1210,7 +1210,7 @@ macro_rules! int_impl {
         #[track_caller]
         pub const fn strict_neg(self) -> Self {
             let (a, b) = self.overflowing_neg();
-            if unlikely!(b) { overflow_panic::neg() } else { a }
+            if b { overflow_panic::neg() } else { a }
         }
 
         /// Checked shift left. Computes `self << rhs`, returning `None` if `rhs` is larger
@@ -1273,7 +1273,7 @@ macro_rules! int_impl {
         #[track_caller]
         pub const fn strict_shl(self, rhs: u32) -> Self {
             let (a, b) = self.overflowing_shl(rhs);
-            if unlikely!(b) { overflow_panic::shl() } else { a }
+            if b { overflow_panic::shl() } else { a }
         }
 
         /// Unchecked shift left. Computes `self << rhs`, assuming that
@@ -1371,7 +1371,7 @@ macro_rules! int_impl {
         #[track_caller]
         pub const fn strict_shr(self, rhs: u32) -> Self {
             let (a, b) = self.overflowing_shr(rhs);
-            if unlikely!(b) { overflow_panic::shr() } else { a }
+            if b { overflow_panic::shr() } else { a }
         }
 
         /// Unchecked shift right. Computes `self >> rhs`, assuming that
@@ -2458,7 +2458,7 @@ macro_rules! int_impl {
                       without modifying the original"]
         pub const fn overflowing_div(self, rhs: Self) -> (Self, bool) {
             // Using `&` helps LLVM see that it is the same check made in division.
-            if unlikely!((self == Self::MIN) & (rhs == -1)) {
+            if (self == Self::MIN) & (rhs == -1) {
                 (self, true)
             } else {
                 (self / rhs, false)
@@ -2489,7 +2489,7 @@ macro_rules! int_impl {
                       without modifying the original"]
         pub const fn overflowing_div_euclid(self, rhs: Self) -> (Self, bool) {
             // Using `&` helps LLVM see that it is the same check made in division.
-            if unlikely!((self == Self::MIN) & (rhs == -1)) {
+            if (self == Self::MIN) & (rhs == -1) {
                 (self, true)
             } else {
                 (self.div_euclid(rhs), false)
@@ -2519,7 +2519,7 @@ macro_rules! int_impl {
         #[must_use = "this returns the result of the operation, \
                       without modifying the original"]
         pub const fn overflowing_rem(self, rhs: Self) -> (Self, bool) {
-            if unlikely!(rhs == -1) {
+            if rhs == -1 {
                 (0, self == Self::MIN)
             } else {
                 (self % rhs, false)
@@ -2551,7 +2551,7 @@ macro_rules! int_impl {
         #[inline]
         #[track_caller]
         pub const fn overflowing_rem_euclid(self, rhs: Self) -> (Self, bool) {
-            if unlikely!(rhs == -1) {
+            if rhs == -1 {
                 (0, self == Self::MIN)
             } else {
                 (self.rem_euclid(rhs), false)
@@ -2580,7 +2580,7 @@ macro_rules! int_impl {
                       without modifying the original"]
         #[allow(unused_attributes)]
         pub const fn overflowing_neg(self) -> (Self, bool) {
-            if unlikely!(self == Self::MIN) {
+            if self == Self::MIN {
                 (Self::MIN, true)
             } else {
                 (-self, false)

diff --git a/library/core/src/num/mod.rs b/library/core/src/num/mod.rs
@@ -19,13 +19,6 @@ macro_rules! try_opt {
     };
 }
 
-#[allow_internal_unstable(const_likely)]
-macro_rules! unlikely {
-    ($e: expr) => {
-        intrinsics::unlikely($e)
-    };
-}
-
 // All these modules are technically private and only exposed for coretests:
 #[cfg(not(no_fp_fmt_parse))]
 pub mod bignum;

diff --git a/library/core/src/num/uint_macros.rs b/library/core/src/num/uint_macros.rs
@@ -456,7 +456,7 @@ macro_rules! uint_impl {
         #[inline]
         pub const fn checked_add(self, rhs: Self) -> Option<Self> {
             let (a, b) = self.overflowing_add(rhs);
-            if unlikely!(b) { None } else { Some(a) }
+            if b { None } else { Some(a) }
         }
 
         /// Strict integer addition. Computes `self + rhs`, panicking
@@ -491,7 +491,7 @@ macro_rules! uint_impl {
         #[track_caller]
         pub const fn strict_add(self, rhs: Self) -> Self {
             let (a, b) = self.overflowing_add(rhs);
-            if unlikely!(b) { overflow_panic ::add()} else {a}
+            if b { overflow_panic ::add()} else {a}
          }
 
         /// Unchecked integer addition. Computes `self + rhs`, assuming overflow
@@ -553,7 +553,7 @@ macro_rules! uint_impl {
         #[inline]
         pub const fn checked_add_signed(self, rhs: $SignedT) -> Option<Self> {
             let (a, b) = self.overflowing_add_signed(rhs);
-            if unlikely!(b) { None } else { Some(a) }
+            if b { None } else { Some(a) }
         }
 
         /// Strict addition with a signed integer. Computes `self + rhs`,
@@ -593,7 +593,7 @@ macro_rules! uint_impl {
         #[track_caller]
         pub const fn strict_add_signed(self, rhs: $SignedT) -> Self {
             let (a, b) = self.overflowing_add_signed(rhs);
-            if unlikely!(b) { overflow_panic ::add()} else {a}
+            if b { overflow_panic ::add()} else {a}
          }
 
         /// Checked integer subtraction. Computes `self - rhs`, returning
@@ -658,7 +658,7 @@ macro_rules! uint_impl {
         #[track_caller]
         pub const fn strict_sub(self, rhs: Self) -> Self {
             let (a, b) = self.overflowing_sub(rhs);
-            if unlikely!(b) { overflow_panic ::sub()} else {a}
+            if b { overflow_panic ::sub()} else {a}
          }
 
         /// Unchecked integer subtraction. Computes `self - rhs`, assuming overflow
@@ -744,7 +744,7 @@ macro_rules! uint_impl {
         #[inline]
         pub const fn checked_mul(self, rhs: Self) -> Option<Self> {
             let (a, b) = self.overflowing_mul(rhs);
-            if unlikely!(b) { None } else { Some(a) }
+            if b { None } else { Some(a) }
         }
 
         /// Strict integer multiplication. Computes `self * rhs`, panicking if
@@ -779,7 +779,7 @@ macro_rules! uint_impl {
         #[track_caller]
         pub const fn strict_mul(self, rhs: Self) -> Self {
             let (a, b) = self.overflowing_mul(rhs);
-            if unlikely!(b) { overflow_panic ::mul()} else {a}
+            if b { overflow_panic ::mul()} else {a}
          }
 
         /// Unchecked integer multiplication. Computes `self * rhs`, assuming overflow
@@ -839,7 +839,7 @@ macro_rules! uint_impl {
                       without modifying the original"]
         #[inline]
         pub const fn checked_div(self, rhs: Self) -> Option<Self> {
-            if unlikely!(rhs == 0) {
+            if rhs == 0 {
                 None
             } else {
                 // SAFETY: div by zero has been checked above and unsigned types have no other
@@ -900,7 +900,7 @@ macro_rules! uint_impl {
                       without modifying the original"]
         #[inline]
         pub const fn checked_div_euclid(self, rhs: Self) -> Option<Self> {
-            if unlikely!(rhs == 0) {
+            if rhs == 0 {
                 None
             } else {
                 Some(self.div_euclid(rhs))
@@ -961,7 +961,7 @@ macro_rules! uint_impl {
                       without modifying the original"]
         #[inline]
         pub const fn checked_rem(self, rhs: Self) -> Option<Self> {
-            if unlikely!(rhs == 0) {
+            if rhs == 0 {
                 None
             } else {
                 // SAFETY: div by zero has been checked above and unsigned types have no other
@@ -1023,7 +1023,7 @@ macro_rules! uint_impl {
                       without modifying the original"]
         #[inline]
         pub const fn checked_rem_euclid(self, rhs: Self) -> Option<Self> {
-            if unlikely!(rhs == 0) {
+            if rhs == 0 {
                 None
             } else {
                 Some(self.rem_euclid(rhs))
@@ -1267,7 +1267,7 @@ macro_rules! uint_impl {
         #[inline]
         pub const fn checked_neg(self) -> Option<Self> {
             let (a, b) = self.overflowing_neg();
-            if unlikely!(b) { None } else { Some(a) }
+            if b { None } else { Some(a) }
         }
 
         /// Strict negation. Computes `-self`, panicking unless `self ==
@@ -1304,7 +1304,7 @@ macro_rules! uint_impl {
         #[track_caller]
         pub const fn strict_neg(self) -> Self {
             let (a, b) = self.overflowing_neg();
-            if unlikely!(b) { overflow_panic::neg() } else { a }
+            if b { overflow_panic::neg() } else { a }
         }
 
         /// Checked shift left. Computes `self << rhs`, returning `None`
@@ -1367,7 +1367,7 @@ macro_rules! uint_impl {
         #[track_caller]
         pub const fn strict_shl(self, rhs: u32) -> Self {
             let (a, b) = self.overflowing_shl(rhs);
-            if unlikely!(b) { overflow_panic::shl() } else { a }
+            if b { overflow_panic::shl() } else { a }
         }
 
         /// Unchecked shift left. Computes `self << rhs`, assuming that
@@ -1465,7 +1465,7 @@ macro_rules! uint_impl {
         #[track_caller]
         pub const fn strict_shr(self, rhs: u32) -> Self {
             let (a, b) = self.overflowing_shr(rhs);
-            if unlikely!(b) { overflow_panic::shr() } else { a }
+            if b { overflow_panic::shr() } else { a }
         }
 
         /// Unchecked shift right. Computes `self >> rhs`, assuming that