--- /dev/null
+Remove unreferenced footnotes which causes a build failure on ubuntu 18.04
+
+diff -u -r ../llvm-6.0.0.src/docs/Proposals/VectorizationPlan.rst ./docs/Proposals/VectorizationPlan.rst
+--- ../llvm-6.0.0.src/docs/Proposals/VectorizationPlan.rst 2017-11-20 13:01:47.000000000 +0100
++++ ./docs/Proposals/VectorizationPlan.rst 2018-04-30 00:30:45.270760735 +0200
+@@ -212,7 +212,7 @@
+ Polly [7]_.
+
+ 3. Loop Vectorizer: the Vectorization Plan aims to upgrade the infrastructure of
+- the Loop Vectorizer and extend it to handle outer loops [8,9]_.
++ the Loop Vectorizer and extend it to handle outer loops [8]_, [9]_.
+
+ References
+ ----------