[clang][bytecode] Diagnose weak reads in final load (#109515)

They aren't allowed here either.

Author: tbaederr

clang/lib/AST/ByteCode/Interp.cpp

@@ -620,6 +620,8 @@ bool CheckFinalLoad(InterpState &S, CodePtr OpPC, const Pointer &Ptr) {
     return false;
   if (!CheckTemporary(S, OpPC, Ptr, AK_Read))
     return false;
+  if (!CheckWeak(S, OpPC, Ptr))
+    return false;
   if (!CheckMutable(S, OpPC, Ptr))
     return false;
   return true;

clang/test/CodeGenCXX/weak-init.cpp

@@ -1,4 +1,5 @@
 // RUN: %clang_cc1 -triple=x86_64-pc-linux-gnu -emit-llvm %s -o - | FileCheck %s
+// RUN: %clang_cc1 -triple=x86_64-pc-linux-gnu -emit-llvm %s -o - -fexperimental-new-constant-interpreter | FileCheck %s
 
 extern const int W __attribute__((weak)) = 99;
 const int S = 77;