[llvm] [flang][runtime] fix intrinsics case of extends_type_of (PR #161466)

[Andre Kuhlenschmidt via llvm-commits]

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@@ -227,6 +227,7 @@ class Descriptor {
   RT_API_ATTRS bool IsPointer() const {
     return raw_.attribute == CFI_attribute_pointer;
   }
+  RT_API_ATTRS bool IsAssociated() const { return raw_.base_addr != nullptr; }
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akuhlens wrote:

Do you mean you would like me to use `IsAllocated`? It seems like I would have to know the underlying representation of the descriptor in order to know that was the right function to call. I can do that, but it adds complexity to the codebase in the form of the implicit knowledge that pointers and allocatable are both represented with the same check in `Descriptor`. I thought about renaming `IsAllocatedOrAssociated` but that would have been a much more pervasive change.

https://github.com/llvm/llvm-project/pull/161466