[clang][Interp] Protect stores against dummy pointers

Author: tbaederr

clang/lib/AST/Interp/Interp.cpp

@@ -399,6 +399,8 @@ bool CheckLoad(InterpState &S, CodePtr OpPC, const Pointer &Ptr) {
 bool CheckStore(InterpState &S, CodePtr OpPC, const Pointer &Ptr) {
   if (!CheckLive(S, OpPC, Ptr, AK_Assign))
     return false;
+  if (!CheckDummy(S, OpPC, Ptr))
+    return false;
   if (!CheckExtern(S, OpPC, Ptr))
     return false;
   if (!CheckRange(S, OpPC, Ptr, AK_Assign))

clang/test/Sema/warn-cast-qual.c

@@ -1,5 +1,6 @@
 // RUN: %clang_cc1 -triple x86_64-unknown-unknown -fsyntax-only -Wcast-qual -verify %s
-// RUN: %clang_cc1 -triple x86_64-unknown-unknown -x c++ -fsyntax-only -Wcast-qual -verify %s
+// RUN: %clang_cc1 -triple x86_64-unknown-unknown -fsyntax-only -Wcast-qual -verify %s -fexperimental-new-constant-interpreter
+// RUN: %clang_cc1 -triple x86_64-unknown-unknown -x c++ -fsyntax-only -Wcast-qual -verify %s -fexperimental-new-constant-interpreter
 
 #include <stdint.h>