Revert "Reland "r364412 [ExpandMemCmp][MergeICmps] Move passes out of CodeGen into opt pipeline.""

This reverts commit r371502, it broke tests
(clang/test/CodeGenCXX/auto-var-init.cpp).

llvm-svn: 371507
diff --git a/llvm/lib/CodeGen/CodeGen.cpp b/llvm/lib/CodeGen/CodeGen.cpp
index 095f86e..d369160 100644
--- a/llvm/lib/CodeGen/CodeGen.cpp
+++ b/llvm/lib/CodeGen/CodeGen.cpp
@@ -31,6 +31,7 @@
   initializeEarlyIfPredicatorPass(Registry);
   initializeEarlyMachineLICMPass(Registry);
   initializeEarlyTailDuplicatePass(Registry);
+  initializeExpandMemCmpPassPass(Registry);
   initializeExpandPostRAPass(Registry);
   initializeFEntryInserterPass(Registry);
   initializeFinalizeISelPass(Registry);