Fix a problem that Eli noticed, and that Doug helped me fix.

git-svn-id: https://llvm.org/svn/llvm-project/cfe/trunk@75265 91177308-0d34-0410-b5e6-96231b3b80d8
diff --git a/lib/CodeGen/CGDebugInfo.cpp b/lib/CodeGen/CGDebugInfo.cpp
index cf8e19a..8fa1e9c 100644
--- a/lib/CodeGen/CGDebugInfo.cpp
+++ b/lib/CodeGen/CGDebugInfo.cpp
@@ -792,8 +792,8 @@
     return Slot = getOrCreateType(cast<TypeOfType>(Ty)->getUnderlyingType(),
                                   Unit);
   case Type::Decltype:
-    return Slot = getOrCreateType(cast<DecltypeType>(Ty)->getUnderlyingExpr()
-                                  ->getType(), Unit);
+    return Slot = getOrCreateType(cast<DecltypeType>(Ty)->getUnderlyingType(),
+                                  Unit);
   }
   
   return Slot;