[ChangeLog] Add entries for SE-0333, -0334, and -0349

# Conflicts:
#	CHANGELOG.md

Author: glessard

CHANGELOG.md

@@ -5,6 +5,72 @@ _**Note:** This is in reverse chronological order, so newer entries are added to
 
 ## Swift 5.7
 
+* [SE-0349][]:
+
+  Loading data from raw memory represented by `UnsafeRawPointer`,
+  `UnsafeRawBufferPointer` and their mutable counterparts now supports unaligned
+  accesses. This previously required a workaround involving an intermediate
+  copy:
+
+  ```swift
+  let result = unalignedData.withUnsafeBytes { buffer -> UInt32 in
+    var storage = UInt32.zero
+    withUnsafeMutableBytes(of: &storage) {
+      $0.copyBytes(from: buffer.prefix(MemoryLayout<UInt32>.size))
+    }
+    return storage
+  }
+  ```
+  Now:
+  ```swift
+  let result = unalignedData.withUnsafeBytes { $0.loadUnaligned(as: UInt32.self) }
+  ```
+  Additionally, the counterpart `storeBytes(of:toByteOffset:as:)` had its
+  alignment restriction lifted, so that storing to arbitrary offsets of raw
+  memory can now succeed.
+
+* [SE-0334][]:
+
+  - `UnsafeRawPointer` and `UnsafeMutableRawPointer` have new functionality for
+  pointer arithmetic, adding functions to obtain a pointer advanced to the next
+  or previous alignment boundary:
+
+    ```swift
+    extension UnsafeRawPointer {
+      public func alignedUp<T>(for: T.type) -> UnsafeRawPointer
+      public func alignedDown<T>(for: T.type) -> UnsafeRawPointer
+      public func alignedUp(toMultipleOf alignment: Int) -> UnsafeRawPointer
+    	public func alignedDown(toMultipleOf alignment: Int) -> UnsafeRawPointer
+    }
+    ```
+  - It is now possible to use a pointer to `struct` to obtain a pointer to one
+  of its stored properties:
+
+    ```swift
+    withUnsafeMutablePointer(to: &myStruct) {
+      let interiorPointer = $0.pointer(to: \.myProperty)!
+      return myCFunction(interiorPointer)
+    }
+    ```
+  - Comparisons between pointers have been simplified by being more permissive.
+  Since pointers are representations of memory locations within a single pool of
+  underlying memory, Swift now allows comparing pointers without requiring type
+  conversions with the `==`, `!=`, `<`,`<=`,`>`, and `>=` operators. 
+
+* [SE-0333][]:
+
+  It is now possible to use the `withMemoryRebound<T>()` method on raw memory,
+  that is `UnsafeRawPointer` , `UnsafeRawBufferPointer` and their mutable
+  counterparts. Additionally, we clarified the semantics of
+  `withMemoryRebound<T>()` when used on typed memory (`UnsafePointer<Pointee>`,
+  `UnsafeBufferPointer<Pointee>` and their mutable counterparts). Whereas
+  `Pointee` and `T` were previously required to have the same stride, you can
+  now rebind in cases where `Pointee` is an aggregate of `T` or vice-versa. For
+  example, given an `UnsafeMutableBufferPointer<CGPoint>`, you can now use
+  `withMemoryRebound` to operate temporarily on a
+  `UnsafeMutableBufferPointer<CGFloat>`, because `CGPoint` is an aggregate of
+  `CGFloat`.
+
 * [SE-0352][]:
 
   It's now possible to call a generic function with a value of protocol type
@@ -9175,6 +9241,8 @@ Swift 1.0
 [SE-0327]: <https://github.com/apple/swift-evolution/blob/main/proposals/0327-actor-initializers.md>
 [SE-0328]: <https://github.com/apple/swift-evolution/blob/main/proposals/0328-structural-opaque-result-types.md>
 [SE-0331]: <https://github.com/apple/swift-evolution/blob/main/proposals/0331-remove-sendable-from-unsafepointer.md>
+[SE-0333]: <https://github.com/apple/swift-evolution/blob/main/proposals/0333-with-memory-rebound.md>
+[SE-0334]: <https://github.com/apple/swift-evolution/blob/main/proposals/0334-pointer-usability-improvements.md>
 [SE-0337]: <https://github.com/apple/swift-evolution/blob/main/proposals/0337-support-incremental-migration-to-concurrency-checking.md>
 [SE-0335]: <https://github.com/apple/swift-evolution/blob/main/proposals/0335-existential-any.md>
 [SE-0341]: <https://github.com/apple/swift-evolution/blob/main/proposals/0341-opaque-parameters.md>
@@ -9184,6 +9252,7 @@ Swift 1.0
 [SE-0345]: <https://github.com/apple/swift-evolution/blob/main/proposals/0345-if-let-shorthand.md>
 [SE-0326]: <https://github.com/apple/swift-evolution/blob/main/proposals/0326-extending-multi-statement-closure-inference.md>
 [SE-0347]: <https://github.com/apple/swift-evolution/blob/main/proposals/0347-type-inference-from-default-exprs.md>
+[SE-0349]: <https://github.com/apple/swift-evolution/blob/main/proposals/0349-unaligned-loads-and-stores.md>
 [SE-0352]: <https://github.com/apple/swift-evolution/blob/main/proposals/0352-implicit-open-existentials.md>
 
 [SR-75]: <https://bugs.swift.org/browse/SR-75>