[MemorySSA & LoopPassManager] Update MemorySSA in formDedicatedExitBlocks.

MemorySSA is now updated when forming dedicated exit blocks.
Resolves PR40037.

llvm-svn: 354623
diff --git a/llvm/lib/Transforms/Utils/LoopUnrollRuntime.cpp b/llvm/lib/Transforms/Utils/LoopUnrollRuntime.cpp
index a9d4194..2f1a759 100644
--- a/llvm/lib/Transforms/Utils/LoopUnrollRuntime.cpp
+++ b/llvm/lib/Transforms/Utils/LoopUnrollRuntime.cpp
@@ -938,11 +938,11 @@
   if (OtherExits.size() > 0) {
     // Generate dedicated exit blocks for the original loop, to preserve
     // LoopSimplifyForm.
-    formDedicatedExitBlocks(L, DT, LI, PreserveLCSSA);
+    formDedicatedExitBlocks(L, DT, LI, nullptr, PreserveLCSSA);
     // Generate dedicated exit blocks for the remainder loop if one exists, to
     // preserve LoopSimplifyForm.
     if (remainderLoop)
-      formDedicatedExitBlocks(remainderLoop, DT, LI, PreserveLCSSA);
+      formDedicatedExitBlocks(remainderLoop, DT, LI, nullptr, PreserveLCSSA);
   }
 
   auto UnrollResult = LoopUnrollResult::Unmodified;