[clang] [clang][PAC] Fix builtins that claim address discriminated types are bitwise compatible (PR #154490)

[John McCall via cfe-commits]

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@@ -74,7 +74,7 @@ static_assert(__is_trivially_destructible(S3));
 static_assert(!__is_trivially_copyable(S3));
 static_assert(!__is_trivially_relocatable(S3)); // expected-warning{{deprecated}}
 //FIXME
-static_assert(__builtin_is_cpp_trivially_relocatable(S3));
+static_assert(!__builtin_is_cpp_trivially_relocatable(S3));
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rjmccall wrote:

Hmm, is this right? My understanding is that, while the pre-standardization concept of trivial relocatability implies bitwise relocation, the standardized concept does not and allows for arbitrary compiler-synthesized logic as long as that logic can't cause arbitrary side-effects. I would expect address-discriminated ptrauth to not disqualify a type from that.

https://github.com/llvm/llvm-project/pull/154490