Extend lvalue evaluation in ExprConstant.cpp to handle CK_LValueBitCast (which is completely trivial). PR8836.

llvm-svn: 141604

clang/lib/AST/ExprConstant.cpp

@@ -481,7 +481,10 @@ public:
       return false;
 
     case CK_NoOp:
+    case CK_LValueBitCast:
       return Visit(E->getSubExpr());
+
+    // FIXME: Support CK_DerivedToBase and friends.
     }
   }
 

clang/test/SemaCXX/i-c-e-cxx.cpp

@@ -57,3 +57,7 @@ int foo() { return A::B; }
 // PR11040
 const int x = 10;
 int* y = reinterpret_cast<const char&>(x); // expected-error {{cannot initialize}}
+
+// This isn't an integral constant expression, but make sure it folds anyway.
+struct PR8836 { char _; long long a; };
+int PR8836test[(__typeof(sizeof(int)))&reinterpret_cast<const volatile char&>((((PR8836*)0)->a))];