[clang] [clang] Implement a bitwise_copyable builtin type trait. (PR #86512)

[Ilya Biryukov via cfe-commits]

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@@ -2749,6 +2749,17 @@ bool QualType::isTriviallyCopyableType(const ASTContext &Context) const {
                                      /*IsCopyConstructible=*/false);
 }
 
+bool QualType::isBitwiseCloneableType(const ASTContext & Context) const {
+  if (const auto *RD = getCanonicalType()->getAsCXXRecordDecl()) {
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ilya-biryukov wrote:

Should we also disallow the objects that return true for `hasNonTrivialObjCLifetime`?
That's the part of the `is_trivially_copyable` that seems relevant. I don't have a good understanding of ObjC, so I'd rather lean on the safe side here. (I.e. maybe there are low-level ways to update the reference counters after `memcpy`, I don't really know. But assuming there aren't, I'd rather lean on the side of returning false for this trait)

https://github.com/llvm/llvm-project/pull/86512