[MemorySSA] Re-enable MemorySSA use.

Differential Revision: https://reviews.llvm.org/D58311

llvm-svn: 370957
diff --git a/llvm/lib/Analysis/MemorySSA.cpp b/llvm/lib/Analysis/MemorySSA.cpp
index ae1e4b8..442d0b4 100644
--- a/llvm/lib/Analysis/MemorySSA.cpp
+++ b/llvm/lib/Analysis/MemorySSA.cpp
@@ -84,7 +84,7 @@
 #endif
 /// Enables memory ssa as a dependency for loop passes in legacy pass manager.
 cl::opt<bool> llvm::EnableMSSALoopDependency(
-    "enable-mssa-loop-dependency", cl::Hidden, cl::init(false),
+    "enable-mssa-loop-dependency", cl::Hidden, cl::init(true),
     cl::desc("Enable MemorySSA dependency for loop pass manager"));
 
 static cl::opt<bool, true>