Initialize the barrier pass llvm::initializeIPO

The barrier pass is a temporary hack, and should go away soon. Nevertheless, if
we don't initialize it, then opt will not understand -barrier, and this will
break bugpoint (because when it dumps the passes from the default pass manager
-barrier will be there).

llvm-svn: 197177
diff --git a/llvm/lib/Transforms/IPO/IPO.cpp b/llvm/lib/Transforms/IPO/IPO.cpp
index 5d563d8..b4d31d8 100644
--- a/llvm/lib/Transforms/IPO/IPO.cpp
+++ b/llvm/lib/Transforms/IPO/IPO.cpp
@@ -44,6 +44,7 @@
   initializeStripDebugDeclarePass(Registry);
   initializeStripDeadDebugInfoPass(Registry);
   initializeStripNonDebugSymbolsPass(Registry);
+  initializeBarrierNoopPass(Registry);
 }
 
 void LLVMInitializeIPO(LLVMPassRegistryRef R) {