[clang] [clang] Implement `__is_pointer_interconvertible_base_of()` (PR #88473)

[Vlad Serebrennikov via cfe-commits]

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@@ -19710,6 +19710,27 @@ bool Sema::IsLayoutCompatible(QualType T1, QualType T2) const {
   return isLayoutCompatible(getASTContext(), T1, T2);
 }
 
+//===-------------- Pointer interconvertibility ----------------------------//
+
+bool Sema::IsPointerInterconvertibleBaseOf(const TypeSourceInfo *Base,
+                                           const TypeSourceInfo *Derived) {
+  QualType BaseT = Base->getType().getCanonicalType().getUnqualifiedType();
+  QualType DerivedT =
+      Derived->getType().getCanonicalType().getUnqualifiedType();
+
+  if (BaseT->isStructureOrClassType() && DerivedT->isStructureOrClassType() &&
+      getASTContext().hasSameType(BaseT, DerivedT))
+    return true;
+
+  if (!IsDerivedFrom(Derived->getTypeLoc().getBeginLoc(), DerivedT, BaseT))
+    return false;
+
+  if (DerivedT->getAsCXXRecordDecl()->isStandardLayout())
+    return true;
----------------
Endilll wrote:

Added.

https://github.com/llvm/llvm-project/pull/88473