Only passes that preserve MemorySSA must mark it as preserved.

Summary:
The method `getLoopPassPreservedAnalyses` should not mark MemorySSA as
preserved, because it's being called in a lot of passes that do not
preserve MemorySSA.
Instead, mark the MemorySSA analysis as preserved by each pass that does
preserve it.
These changes only affect the new pass mananger.

Reviewers: chandlerc

Subscribers: mehdi_amini, jlebar, Prazek, george.burgess.iv, llvm-commits

Tags: #llvm

Differential Revision: https://reviews.llvm.org/D62536

llvm-svn: 363091
diff --git a/llvm/lib/Transforms/Scalar/LoopInstSimplify.cpp b/llvm/lib/Transforms/Scalar/LoopInstSimplify.cpp
index 6df32b0..31191b5 100644
--- a/llvm/lib/Transforms/Scalar/LoopInstSimplify.cpp
+++ b/llvm/lib/Transforms/Scalar/LoopInstSimplify.cpp
@@ -233,6 +233,8 @@
 
   auto PA = getLoopPassPreservedAnalyses();
   PA.preserveSet<CFGAnalyses>();
+  if (EnableMSSALoopDependency)
+    PA.preserve<MemorySSAAnalysis>();
   return PA;
 }