implement codegen support for preinc as an lvalue, PR5514.

llvm-svn: 93076
diff --git a/clang/test/CodeGenCXX/expr.cpp b/clang/test/CodeGenCXX/expr.cpp
index 6d641dc..d92cfb4 100644
--- a/clang/test/CodeGenCXX/expr.cpp
+++ b/clang/test/CodeGenCXX/expr.cpp
@@ -10,3 +10,7 @@
   char *xpto;
   while ( true && xpto[0] );
 }
+
+// PR5514
+int a;
+void test2() { ++a+=10; }