[AliasAnalysis] AAResults preserves AAManager.

Summary:
AAResults should not invalidate AAManager.
Update tests.

Reviewers: chandlerc

Subscribers: mehdi_amini, jlebar, llvm-commits

Tags: #llvm

Differential Revision: https://reviews.llvm.org/D60914

llvm-svn: 359014

1 files changed, 4 insertions, 6 deletions

diff --git a/llvm/lib/Analysis/AliasAnalysis.cpp b/llvm/lib/Analysis/AliasAnalysis.cpp
index 06a33f659c1..4bb3b80511a 100644
--- a/llvm/lib/Analysis/AliasAnalysis.cpp
+++ b/llvm/lib/Analysis/AliasAnalysis.cpp
@@ -79,12 +79,10 @@ AAResults::~AAResults() {
 
 bool AAResults::invalidate(Function &F, const PreservedAnalyses &PA,
                            FunctionAnalysisManager::Invalidator &Inv) {
-  // Check if the AA manager itself has been invalidated.
-  auto PAC = PA.getChecker<AAManager>();
-  if (!PAC.preserved() && !PAC.preservedSet<AllAnalysesOn<Function>>())
-    return true; // The manager needs to be blown away, clear everything.
-
-  // Check all of the dependencies registered.
+  // AAResults preserves the AAManager by default, due to the stateless nature
+  // of AliasAnalysis. There is no need to check whether it has been preserved
+  // explicitly. However, we still need to check if any of the dependencies end
+  // up being invalidated, and invalidate ourselves in that case.
   for (AnalysisKey *ID : AADeps)
     if (Inv.invalidate(ID, F, PA))
       return true;