Don't try to emit CK_LValueBitCast casts as constants. PR9558.

llvm-svn: 142863

clang/lib/CodeGen/CGExprConstant.cpp

@@ -573,7 +573,6 @@ public:
     case CK_CPointerToObjCPointerCast:
     case CK_BlockPointerToObjCPointerCast:
     case CK_AnyPointerToBlockPointerCast:
-    case CK_LValueBitCast:
     case CK_BitCast:
       if (C->getType() == destType) return C;
       return llvm::ConstantExpr::getBitCast(C, destType);
@@ -589,6 +588,7 @@ public:
     case CK_ARCConsumeObject:
     case CK_ARCReclaimReturnedObject:
     case CK_ARCExtendBlockObject:
+    case CK_LValueBitCast:
       return 0;
 
     // These might need to be supported for constexpr.

clang/test/CodeGenCXX/const-init.cpp

@@ -36,3 +36,7 @@ namespace test2 {
   double t0 = A::d;
   double t1[] = { A::d, A::f };
 }
+
+// We don't expect to fold this in the frontend, but make sure it doesn't crash.
+// CHECK: @PR9558 = global float 0.000000e+0
+float PR9558 = reinterpret_cast<const float&>("asd");