From fbcafb85c587cf20bd6550cfb6510c3b20c4c61a Mon Sep 17 00:00:00 2001
From: Maybe Waffle <waffle.lapkin@gmail.com>
Date: Fri, 5 Aug 2022 17:11:47 +0400
Subject: [PATCH] Optimize `pointer::as_aligned_to`

---
 core/src/ptr/const_ptr.rs | 5 +----
 core/src/ptr/mut_ptr.rs   | 5 +----
 2 files changed, 2 insertions(+), 8 deletions(-)

diff --git a/core/src/ptr/const_ptr.rs b/core/src/ptr/const_ptr.rs
index e0655d68d..2cd6e23c7 100644
--- a/core/src/ptr/const_ptr.rs
+++ b/core/src/ptr/const_ptr.rs
@@ -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
     }
 }
 
diff --git a/core/src/ptr/mut_ptr.rs b/core/src/ptr/mut_ptr.rs
index fc3dd2a9b..56ad5f765 100644
--- a/core/src/ptr/mut_ptr.rs
+++ b/core/src/ptr/mut_ptr.rs
@@ -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
     }
 }