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Optimize pointer::is_aligned_to #100169

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Aug 7, 2022
Merged

Optimize pointer::is_aligned_to #100169

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5 changes: 1 addition & 4 deletions library/core/src/ptr/const_ptr.rs
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Original file line number Diff line number Diff line change
Expand Up @@ -1336,11 +1336,8 @@ impl<T: ?Sized> *const T {
panic!("is_aligned_to: align is not a power-of-two");
}

// SAFETY: `is_power_of_two()` will return `false` for zero.
unsafe { core::intrinsics::assume(align != 0) };

// Cast is needed for `T: !Sized`
self.cast::<u8>().addr() % align == 0
self.cast::<u8>().addr() & align - 1 == 0
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@lygstate lygstate Aug 9, 2022 •
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self.cast::<u8>().addr() & (align - 1) == 0 are easier to understand

}
}

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5 changes: 1 addition & 4 deletions library/core/src/ptr/mut_ptr.rs
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Original file line number Diff line number Diff line change
Expand Up @@ -1614,11 +1614,8 @@ impl<T: ?Sized> *mut T {
panic!("is_aligned_to: align is not a power-of-two");
}

// SAFETY: `is_power_of_two()` will return `false` for zero.
unsafe { core::intrinsics::assume(align != 0) };

// Cast is needed for `T: !Sized`
self.cast::<u8>().addr() % align == 0
self.cast::<u8>().addr() & align - 1 == 0
}
}

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