[clang][Interp] Fix returning primitive non-blockpointers

We can't deref() them, so return false here.

Author: tbaederr

clang/lib/AST/Interp/Pointer.cpp

@@ -347,7 +347,7 @@ std::optional<APValue> Pointer::toRValue(const Context &Ctx) const {
       Ty = AT->getValueType();
 
     // Invalid pointers.
-    if (Ptr.isDummy() || !Ptr.isLive() ||
+    if (Ptr.isDummy() || !Ptr.isLive() || !Ptr.isBlockPointer() ||
         (!Ptr.isUnknownSizeArray() && Ptr.isOnePastEnd()))
       return false;
 

clang/test/AST/Interp/literals.cpp

@@ -45,6 +45,8 @@ constexpr int Failed2 = Failed1 + 1; // both-error {{must be initialized by a co
 static_assert(Failed2 == 0, ""); // both-error {{not an integral constant expression}} \
                                  // both-note {{initializer of 'Failed2' is not a constant expression}}
 
+const int x = *(volatile int*)0x1234;
+
 namespace ScalarTypes {
   constexpr int ScalarInitInt = int();
   static_assert(ScalarInitInt == 0, "");