diff --git a/library/core/src/num/int_macros.rs b/library/core/src/num/int_macros.rs
index bd2f7445612a7..a4efbaf6ad23c 100644
--- a/library/core/src/num/int_macros.rs
+++ b/library/core/src/num/int_macros.rs
@@ -209,6 +209,48 @@ macro_rules! int_impl {
             self & self.wrapping_neg()
         }
 
+        /// Returns the index of the highest bit set to one in `self`, or `None`
+        /// if `self` is `0`.
+        ///
+        /// # Examples
+        ///
+        /// ```
+        /// #![feature(int_lowest_highest_one)]
+        ///
+        #[doc = concat!("assert_eq!(0x0_", stringify!($SelfT), ".highest_one(), None);")]
+        #[doc = concat!("assert_eq!(0x1_", stringify!($SelfT), ".highest_one(), Some(0));")]
+        #[doc = concat!("assert_eq!(0x10_", stringify!($SelfT), ".highest_one(), Some(4));")]
+        #[doc = concat!("assert_eq!(0x1f_", stringify!($SelfT), ".highest_one(), Some(4));")]
+        /// ```
+        #[unstable(feature = "int_lowest_highest_one", issue = "145203")]
+        #[must_use = "this returns the result of the operation, \
+                      without modifying the original"]
+        #[inline(always)]
+        pub const fn highest_one(self) -> Option<u32> {
+            (self as $UnsignedT).highest_one()
+        }
+
+        /// Returns the index of the lowest bit set to one in `self`, or `None`
+        /// if `self` is `0`.
+        ///
+        /// # Examples
+        ///
+        /// ```
+        /// #![feature(int_lowest_highest_one)]
+        ///
+        #[doc = concat!("assert_eq!(0x0_", stringify!($SelfT), ".lowest_one(), None);")]
+        #[doc = concat!("assert_eq!(0x1_", stringify!($SelfT), ".lowest_one(), Some(0));")]
+        #[doc = concat!("assert_eq!(0x10_", stringify!($SelfT), ".lowest_one(), Some(4));")]
+        #[doc = concat!("assert_eq!(0x1f_", stringify!($SelfT), ".lowest_one(), Some(0));")]
+        /// ```
+        #[unstable(feature = "int_lowest_highest_one", issue = "145203")]
+        #[must_use = "this returns the result of the operation, \
+                      without modifying the original"]
+        #[inline(always)]
+        pub const fn lowest_one(self) -> Option<u32> {
+            (self as $UnsignedT).lowest_one()
+        }
+
         /// Returns the bit pattern of `self` reinterpreted as an unsigned integer of the same size.
         ///
         /// This produces the same result as an `as` cast, but ensures that the bit-width remains
diff --git a/library/core/src/num/nonzero.rs b/library/core/src/num/nonzero.rs
index 308d722f5d564..e02d9260a1690 100644
--- a/library/core/src/num/nonzero.rs
+++ b/library/core/src/num/nonzero.rs
@@ -681,6 +681,54 @@ macro_rules! nonzero_integer {
                 unsafe { NonZero::new_unchecked(n) }
             }
 
+            /// Returns the index of the highest bit set to one in `self`.
+            ///
+            /// # Examples
+            ///
+            /// ```
+            /// #![feature(int_lowest_highest_one)]
+            ///
+            /// # use core::num::NonZero;
+            /// # fn main() { test().unwrap(); }
+            /// # fn test() -> Option<()> {
+            #[doc = concat!("assert_eq!(NonZero::<", stringify!($Int), ">::new(0x1)?.highest_one(), 0);")]
+            #[doc = concat!("assert_eq!(NonZero::<", stringify!($Int), ">::new(0x10)?.highest_one(), 4);")]
+            #[doc = concat!("assert_eq!(NonZero::<", stringify!($Int), ">::new(0x1f)?.highest_one(), 4);")]
+            /// # Some(())
+            /// # }
+            /// ```
+            #[unstable(feature = "int_lowest_highest_one", issue = "145203")]
+            #[must_use = "this returns the result of the operation, \
+                          without modifying the original"]
+            #[inline(always)]
+            pub const fn highest_one(self) -> u32 {
+                Self::BITS - 1 - self.leading_zeros()
+            }
+
+            /// Returns the index of the lowest bit set to one in `self`.
+            ///
+            /// # Examples
+            ///
+            /// ```
+            /// #![feature(int_lowest_highest_one)]
+            ///
+            /// # use core::num::NonZero;
+            /// # fn main() { test().unwrap(); }
+            /// # fn test() -> Option<()> {
+            #[doc = concat!("assert_eq!(NonZero::<", stringify!($Int), ">::new(0x1)?.lowest_one(), 0);")]
+            #[doc = concat!("assert_eq!(NonZero::<", stringify!($Int), ">::new(0x10)?.lowest_one(), 4);")]
+            #[doc = concat!("assert_eq!(NonZero::<", stringify!($Int), ">::new(0x1f)?.lowest_one(), 0);")]
+            /// # Some(())
+            /// # }
+            /// ```
+            #[unstable(feature = "int_lowest_highest_one", issue = "145203")]
+            #[must_use = "this returns the result of the operation, \
+                          without modifying the original"]
+            #[inline(always)]
+            pub const fn lowest_one(self) -> u32 {
+                self.trailing_zeros()
+            }
+
             /// Returns the number of ones in the binary representation of `self`.
             ///
             /// # Examples
diff --git a/library/core/src/num/uint_macros.rs b/library/core/src/num/uint_macros.rs
index 2c9a119684963..34638f9a799e5 100644
--- a/library/core/src/num/uint_macros.rs
+++ b/library/core/src/num/uint_macros.rs
@@ -261,6 +261,54 @@ macro_rules! uint_impl {
             self & self.wrapping_neg()
         }
 
+        /// Returns the index of the highest bit set to one in `self`, or `None`
+        /// if `self` is `0`.
+        ///
+        /// # Examples
+        ///
+        /// ```
+        /// #![feature(int_lowest_highest_one)]
+        ///
+        #[doc = concat!("assert_eq!(0x0_", stringify!($SelfT), ".highest_one(), None);")]
+        #[doc = concat!("assert_eq!(0x1_", stringify!($SelfT), ".highest_one(), Some(0));")]
+        #[doc = concat!("assert_eq!(0x10_", stringify!($SelfT), ".highest_one(), Some(4));")]
+        #[doc = concat!("assert_eq!(0x1f_", stringify!($SelfT), ".highest_one(), Some(4));")]
+        /// ```
+        #[unstable(feature = "int_lowest_highest_one", issue = "145203")]
+        #[must_use = "this returns the result of the operation, \
+                      without modifying the original"]
+        #[inline(always)]
+        pub const fn highest_one(self) -> Option<u32> {
+            match NonZero::new(self) {
+                Some(v) => Some(v.highest_one()),
+                None => None,
+            }
+        }
+
+        /// Returns the index of the lowest bit set to one in `self`, or `None`
+        /// if `self` is `0`.
+        ///
+        /// # Examples
+        ///
+        /// ```
+        /// #![feature(int_lowest_highest_one)]
+        ///
+        #[doc = concat!("assert_eq!(0x0_", stringify!($SelfT), ".lowest_one(), None);")]
+        #[doc = concat!("assert_eq!(0x1_", stringify!($SelfT), ".lowest_one(), Some(0));")]
+        #[doc = concat!("assert_eq!(0x10_", stringify!($SelfT), ".lowest_one(), Some(4));")]
+        #[doc = concat!("assert_eq!(0x1f_", stringify!($SelfT), ".lowest_one(), Some(0));")]
+        /// ```
+        #[unstable(feature = "int_lowest_highest_one", issue = "145203")]
+        #[must_use = "this returns the result of the operation, \
+                      without modifying the original"]
+        #[inline(always)]
+        pub const fn lowest_one(self) -> Option<u32> {
+            match NonZero::new(self) {
+                Some(v) => Some(v.lowest_one()),
+                None => None,
+            }
+        }
+
         /// Returns the bit pattern of `self` reinterpreted as a signed integer of the same size.
         ///
         /// This produces the same result as an `as` cast, but ensures that the bit-width remains
diff --git a/library/coretests/tests/lib.rs b/library/coretests/tests/lib.rs
index 0c4d49f3c994b..3781285686da3 100644
--- a/library/coretests/tests/lib.rs
+++ b/library/coretests/tests/lib.rs
@@ -54,6 +54,7 @@
 #![feature(generic_assert_internals)]
 #![feature(hasher_prefixfree_extras)]
 #![feature(hashmap_internals)]
+#![feature(int_lowest_highest_one)]
 #![feature(int_roundings)]
 #![feature(ip)]
 #![feature(ip_from)]
diff --git a/library/coretests/tests/nonzero.rs b/library/coretests/tests/nonzero.rs
index eb06c34fd0205..69e4ed9c36b3a 100644
--- a/library/coretests/tests/nonzero.rs
+++ b/library/coretests/tests/nonzero.rs
@@ -462,3 +462,111 @@ fn test_nonzero_fmt() {
 
     assert_eq!(i, nz);
 }
+
+#[test]
+fn test_nonzero_highest_one() {
+    macro_rules! nonzero_int_impl {
+        ($($T:ty),+) => {
+            $(
+                {
+                    for i in 0..<$T>::BITS {
+                        // Set single bit.
+                        assert_eq!(NonZero::<$T>::new(1 << i).unwrap().highest_one(), i);
+                        if i > <$T>::BITS {
+                            // Set lowest bits.
+                            assert_eq!(
+                                NonZero::<$T>::new(<$T>::MAX >> i).unwrap().highest_one(),
+                                <$T>::BITS - i - 2,
+                            );
+                        }
+                        // Set highest bits.
+                        assert_eq!(
+                            NonZero::<$T>::new(-1 << i).unwrap().highest_one(),
+                            <$T>::BITS - 1,
+                        );
+                    }
+                }
+            )+
+        };
+    }
+
+    macro_rules! nonzero_uint_impl {
+        ($($T:ty),+) => {
+            $(
+                {
+                    for i in 0..<$T>::BITS {
+                        // Set single bit.
+                        assert_eq!(NonZero::<$T>::new(1 << i).unwrap().highest_one(), i);
+                        // Set lowest bits.
+                        assert_eq!(
+                            NonZero::<$T>::new(<$T>::MAX >> i).unwrap().highest_one(),
+                            <$T>::BITS - i - 1,
+                        );
+                        // Set highest bits.
+                        assert_eq!(
+                            NonZero::<$T>::new(<$T>::MAX << i).unwrap().highest_one(),
+                            <$T>::BITS - 1,
+                        );
+                    }
+                }
+            )+
+        };
+    }
+
+    nonzero_int_impl!(i8, i16, i32, i64, i128, isize);
+    nonzero_uint_impl!(u8, u16, u32, u64, u128, usize);
+}
+
+#[test]
+fn test_nonzero_lowest_one() {
+    macro_rules! nonzero_int_impl {
+        ($($T:ty),+) => {
+            $(
+                {
+                    for i in 0..<$T>::BITS {
+                        // Set single bit.
+                        assert_eq!(NonZero::<$T>::new(1 << i).unwrap().lowest_one(), i);
+                        if i > <$T>::BITS {
+                            // Set lowest bits.
+                            assert_eq!(
+                                NonZero::<$T>::new(<$T>::MAX >> i).unwrap().lowest_one(),
+                                0,
+                            );
+                        }
+                        // Set highest bits.
+                        assert_eq!(
+                            NonZero::<$T>::new(-1 << i).unwrap().lowest_one(),
+                            i,
+                        );
+                    }
+                }
+            )+
+        };
+    }
+
+    macro_rules! nonzero_uint_impl {
+        ($($T:ty),+) => {
+            $(
+                {
+                    for i in 0..<$T>::BITS {
+                        // Set single bit.
+                        assert_eq!(NonZero::<$T>::new(1 << i).unwrap().lowest_one(), i);
+                        // Set lowest bits.
+                        assert_eq!(
+                            NonZero::<$T>::new(<$T>::MAX >> i).unwrap().lowest_one(),
+                            0,
+                        );
+                        // Set highest bits.
+                        assert_eq!(
+                            NonZero::<$T>::new(<$T>::MAX << i).unwrap().lowest_one(),
+                            i,
+                        );
+                    }
+                }
+            )+
+        };
+    }
+
+    nonzero_int_impl!(i8, i16, i32, i64, i128, isize);
+    nonzero_uint_impl!(u8, u16, u32, u64, u128, usize);
+}
diff --git a/library/coretests/tests/num/int_macros.rs b/library/coretests/tests/num/int_macros.rs
index ca32fce861f8c..1611a6466f5ab 100644
--- a/library/coretests/tests/num/int_macros.rs
+++ b/library/coretests/tests/num/int_macros.rs
@@ -227,6 +227,46 @@ macro_rules! int_module {
             }
         }
 
+        #[test]
+        fn test_highest_one() {
+            const ZERO: $T = 0;
+            const ONE: $T = 1;
+            const MINUS_ONE: $T = -1;
+
+            assert_eq!(ZERO.highest_one(), None);
+
+            for i in 0..<$T>::BITS {
+                // Set single bit.
+                assert_eq!((ONE << i).highest_one(), Some(i));
+                if i != <$T>::BITS - 1 {
+                    // Set lowest bits.
+                    assert_eq!((<$T>::MAX >> i).highest_one(), Some(<$T>::BITS - i - 2));
+                }
+                // Set highest bits.
+                assert_eq!((MINUS_ONE << i).highest_one(), Some(<$T>::BITS - 1));
+            }
+        }
+
+        #[test]
+        fn test_lowest_one() {
+            const ZERO: $T = 0;
+            const ONE: $T = 1;
+            const MINUS_ONE: $T = -1;
+
+            assert_eq!(ZERO.lowest_one(), None);
+
+            for i in 0..<$T>::BITS {
+                // Set single bit.
+                assert_eq!((ONE << i).lowest_one(), Some(i));
+                if i != <$T>::BITS - 1 {
+                    // Set lowest bits.
+                    assert_eq!((<$T>::MAX >> i).lowest_one(), Some(0));
+                }
+                // Set highest bits.
+                assert_eq!((MINUS_ONE << i).lowest_one(), Some(i));
+            }
+        }
+
         #[test]
         fn test_from_str() {
             fn from_str<T: std::str::FromStr>(t: &str) -> Option<T> {
diff --git a/library/coretests/tests/num/uint_macros.rs b/library/coretests/tests/num/uint_macros.rs
index 8f389de70aa2e..c7d10ea4d880a 100644
--- a/library/coretests/tests/num/uint_macros.rs
+++ b/library/coretests/tests/num/uint_macros.rs
@@ -184,6 +184,40 @@ macro_rules! uint_module {
             }
         }
 
+        #[test]
+        fn test_highest_one() {
+            const ZERO: $T = 0;
+            const ONE: $T = 1;
+
+            assert_eq!(ZERO.highest_one(), None);
+
+            for i in 0..<$T>::BITS {
+                // Set single bit.
+                assert_eq!((ONE << i).highest_one(), Some(i));
+                // Set lowest bits.
+                assert_eq!((<$T>::MAX >> i).highest_one(), Some(<$T>::BITS - i - 1));
+                // Set highest bits.
+                assert_eq!((<$T>::MAX << i).highest_one(), Some(<$T>::BITS - 1));
+            }
+        }
+
+        #[test]
+        fn test_lowest_one() {
+            const ZERO: $T = 0;
+            const ONE: $T = 1;
+
+            assert_eq!(ZERO.lowest_one(), None);
+
+            for i in 0..<$T>::BITS {
+                // Set single bit.
+                assert_eq!((ONE << i).lowest_one(), Some(i));
+                // Set lowest bits.
+                assert_eq!((<$T>::MAX >> i).lowest_one(), Some(0));
+                // Set highest bits.
+                assert_eq!((<$T>::MAX << i).lowest_one(), Some(i));
+            }
+        }
+
         fn from_str<T: core::str::FromStr>(t: &str) -> Option<T> {
             core::str::FromStr::from_str(t).ok()
         }