Update CGExprConstant for change to emit padding values as undef.
 - This fixes 2003-05-21-BitfieldHandling.

git-svn-id: https://llvm.org/svn/llvm-project/cfe/trunk@90876 91177308-0d34-0410-b5e6-96231b3b80d8
diff --git a/lib/CodeGen/CGExprConstant.cpp b/lib/CodeGen/CGExprConstant.cpp
index 9289f78..d428983 100644
--- a/lib/CodeGen/CGExprConstant.cpp
+++ b/lib/CodeGen/CGExprConstant.cpp
@@ -167,7 +167,11 @@
       }
 
       // Or in the bits that go into the previous byte.
-      Tmp |= cast<llvm::ConstantInt>(Elements.back())->getValue();
+      if (llvm::ConstantInt *Val = dyn_cast<llvm::ConstantInt>(Elements.back()))
+        Tmp |= Val->getValue();
+      else
+        assert(isa<llvm::UndefValue>(Elements.back()));
+
       Elements.back() = llvm::ConstantInt::get(CGM.getLLVMContext(), Tmp);
 
       if (FitsCompletelyInPreviousByte)