[clang][bytecode] Tighten double-destroy check (#129528)

The instance pointer of the current function being the same as the one
we're destroying is only relevant if said function is also a destructor.

Author: tbaederr

clang/lib/AST/ByteCode/Interp.cpp

@@ -992,7 +992,8 @@ static bool runRecordDestructor(InterpState &S, CodePtr OpPC,
   const Record *R = Desc->ElemRecord;
   assert(R);
 
-  if (Pointer::pointToSameBlock(BasePtr, S.Current->getThis())) {
+  if (Pointer::pointToSameBlock(BasePtr, S.Current->getThis()) &&
+      S.Current->getFunction()->isDestructor()) {
     const SourceInfo &Loc = S.Current->getSource(OpPC);
     S.FFDiag(Loc, diag::note_constexpr_double_destroy);
     return false;

clang/test/AST/ByteCode/new-delete.cpp

@@ -558,6 +558,11 @@ namespace DeleteThis {
   }
   static_assert(super_secret_double_delete()); // both-error {{not an integral constant expression}} \
                                                // both-note {{in call to 'super_secret_double_delete()'}}
+
+  struct B {
+    constexpr void reset() { delete this; }
+  };
+  static_assert(((new B)->reset(), true));
 }
 
 namespace CastedDelete {