<table border="1" cellspacing="0" cellpadding="8">
    <tr>
        <th>Issue</th>
        <td>
            <a href=https://github.com/llvm/llvm-project/issues/81369>81369</a>
        </td>
    </tr>

    <tr>
        <th>Summary</th>
        <td>
            Subclasses of subclasses of NSObject are part of the non-fragile abi even when direct subclasses of NSObject are not
        </td>
    </tr>

    <tr>
      <th>Labels</th>
      <td>
            new issue
      </td>
    </tr>

    <tr>
      <th>Assignees</th>
      <td>
      </td>
    </tr>

    <tr>
      <th>Reporter</th>
      <td>
          AtariDreams
      </td>
    </tr>
</table>

<pre>
    Even when the offsets are fixed, clang is assuming classes that can be proven to inherit from classes that inherit from NSObject and so on are not fixed-width, even though they are and a lot of missed optimizations are because of it. 

@"OBJC_IVAR_$_StaticLayoutSubClass.static_layout_ivar2" = hidden global i64 24

it should be hidden constant i64 24

@interface NSObject {
  int these, will, never, change, ever;
}
@end

@interface StaticLayout : NSObject
@end

@implementation StaticLayout {
  int static_layout_ivar;
}
-(void)meth {
  static_layout_ivar = 0;
 // CHECK-NOT: load i64, ptr @"OBJC_IVAR_$_StaticLayout
}
@end

@interface StaticLayoutSubClass : StaticLayout
@end

@implementation StaticLayoutSubClass {
  int static_layout_ivar2;
}
-(void)meth2 {
  static_layout_ivar2 = 0;
  // CHECK: load i64, ptr @"OBJC_IVAR_$_StaticLayoutSubClass
  // CHECK-NOT: load i64, ptr @"OBJC_IVAR_$_StaticLayoutSubClass
}
@end

</pre>
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