Index: llvm/lib/Transforms/Scalar/LoopSink.cpp
===================================================================
--- llvm/lib/Transforms/Scalar/LoopSink.cpp
+++ llvm/lib/Transforms/Scalar/LoopSink.cpp
@@ -70,7 +70,7 @@
     cl::desc("Enable MemorySSA for LoopSink in new pass manager"));
 
 static cl::opt<bool> EnableMSSAInLegacyLoopSink(
-    "enable-mssa-in-legacy-loop-sink", cl::Hidden, cl::init(false),
+    "enable-mssa-in-legacy-loop-sink", cl::Hidden, cl::init(true),
     cl::desc("Enable MemorySSA for LoopSink in legacy pass manager"));
 
 /// Return adjusted total frequency of \p BBs.