[PATCH] XCore target: fix bug in dereferencing null pointer.

[Richard Osborne]

LGTM

================
Comment at: test/CodeGen/xcore-abi.cpp:17
@@ +16,3 @@
+
+// Make sure null 'VarDecl*' are not indirected.
+class C {
----------------
This comment could be made clearer. What was the actual bug? Did it crash when emitting the destructor or did it crash because of an implicitly generated method?

http://reviews.llvm.org/D3450