[LICM] Preserve DT and LoopInfo specifically

Summary:
In LICM, CFG could be changed in splitPredecessorsOfLoopExit(), which update
only DT and LoopInfo. Therefore, we should preserve only DT and LoopInfo specifically,
instead of all analyses that depend on the CFG (setPreservesCFG()).

This change should fix PR37323.

Reviewers: uabelho, davide, dberlin, Ka-Ka

Reviewed By: dberlin

Subscribers: mzolotukhin, bjope, mcrosier, llvm-commits

Differential Revision: https://reviews.llvm.org/D46775

llvm-svn: 333198

1 files changed, 6 insertions, 2 deletions

diff --git a/llvm/lib/Transforms/Scalar/LICM.cpp b/llvm/lib/Transforms/Scalar/LICM.cpp
index 8c0747782d7..98599dea050 100644
--- a/llvm/lib/Transforms/Scalar/LICM.cpp
+++ b/llvm/lib/Transforms/Scalar/LICM.cpp
@@ -170,7 +170,8 @@ struct LegacyLICMPass : public LoopPass {
   /// loop preheaders be inserted into the CFG...
   ///
   void getAnalysisUsage(AnalysisUsage &AU) const override {
-    AU.setPreservesCFG();
+    AU.addPreserved<DominatorTreeWrapperPass>();
+    AU.addPreserved<LoopInfoWrapperPass>();
     AU.addRequired<TargetLibraryInfoWrapperPass>();
     if (EnableMSSALoopDependency)
       AU.addRequired<MemorySSAWrapperPass>();
@@ -220,7 +221,10 @@ PreservedAnalyses LICMPass::run(Loop &L, LoopAnalysisManager &AM,
     return PreservedAnalyses::all();
 
   auto PA = getLoopPassPreservedAnalyses();
-  PA.preserveSet<CFGAnalyses>();
+
+  PA.preserve<DominatorTreeAnalysis>();
+  PA.preserve<LoopAnalysis>();
+
   return PA;
 }