From 4ea24c84fb56fe1834d0b537c1d706bcb3199013 Mon Sep 17 00:00:00 2001
From: Daniel Berlin <dberlin@dberlin.org>
Date: Fri, 22 May 2015 00:13:05 +0000
Subject: [PATCH] MergedLoadStoreMotion preserves MemoryDependenceAnalysis, it
 does not require it. (It already was coded assuming it can sometimes be null,
 so no other changes are necessary)

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@237978 91177308-0d34-0410-b5e6-96231b3b80d8
---
 lib/Transforms/Scalar/MergedLoadStoreMotion.cpp | 4 ++--
 1 file changed, 2 insertions(+), 2 deletions(-)

diff --git a/lib/Transforms/Scalar/MergedLoadStoreMotion.cpp b/lib/Transforms/Scalar/MergedLoadStoreMotion.cpp
index 73f42961cb1..611a941b0b2 100644
--- a/lib/Transforms/Scalar/MergedLoadStoreMotion.cpp
+++ b/lib/Transforms/Scalar/MergedLoadStoreMotion.cpp
@@ -117,8 +117,8 @@ private:
   // This transformation requires dominator postdominator info
   void getAnalysisUsage(AnalysisUsage &AU) const override {
     AU.addRequired<TargetLibraryInfoWrapperPass>();
-    AU.addRequired<MemoryDependenceAnalysis>();
     AU.addRequired<AliasAnalysis>();
+    AU.addPreserved<MemoryDependenceAnalysis>();
     AU.addPreserved<AliasAnalysis>();
   }
 
@@ -580,7 +580,7 @@ bool MergedLoadStoreMotion::mergeStores(BasicBlock *T) {
 /// \brief Run the transformation for each function
 ///
 bool MergedLoadStoreMotion::runOnFunction(Function &F) {
-  MD = &getAnalysis<MemoryDependenceAnalysis>();
+  MD = getAnalysisIfAvailable<MemoryDependenceAnalysis>();
   AA = &getAnalysis<AliasAnalysis>();
 
   bool Changed = false;