Index: lib/Analysis/AliasAnalysis.cpp
===================================================================
--- lib/Analysis/AliasAnalysis.cpp
+++ lib/Analysis/AliasAnalysis.cpp
@@ -79,10 +79,8 @@
 
 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.
+  // AAResults preserves the AAManager by default, due to the stateless nature
+  // of AliasAnalysis. Do not invalidate it here.
 
   // Check all of the dependencies registered.
   for (AnalysisKey *ID : AADeps)
Index: test/Analysis/MemoryDependenceAnalysis/invalidation.ll
===================================================================
--- test/Analysis/MemoryDependenceAnalysis/invalidation.ll
+++ test/Analysis/MemoryDependenceAnalysis/invalidation.ll
@@ -1,17 +1,16 @@
 ; Test that memdep gets invalidated when the analyses it depends on are
 ; invalidated.
 ;
-; Check AA specifically.
+; Check AA. AA is stateless, there's nothing to invalidate.
 ; RUN: opt -disable-output -debug-pass-manager -aa-pipeline='basic-aa' %s 2>&1 \
 ; RUN:     -passes='require<memdep>,invalidate<aa>,gvn' \
 ; RUN:     | FileCheck %s --check-prefix=CHECK-AA-INVALIDATE
 ; CHECK-AA-INVALIDATE: Running pass: RequireAnalysisPass
 ; CHECK-AA-INVALIDATE: Running analysis: MemoryDependenceAnalysis
 ; CHECK-AA-INVALIDATE: Running pass: InvalidateAnalysisPass
-; CHECK-AA-INVALIDATE: Invalidating analysis: AAManager
-; CHECK-AA-INVALIDATE: Invalidating analysis: MemoryDependenceAnalysis
+; CHECK-NOT-AA-INVALIDATE: Invalidating analysis: MemoryDependenceAnalysis
 ; CHECK-AA-INVALIDATE: Running pass: GVN
-; CHECK-AA-INVALIDATE: Running analysis: MemoryDependenceAnalysis
+; CHECK-NOT-AA-INVALIDATE: Running analysis: MemoryDependenceAnalysis
 ;
 ; Check domtree specifically.
 ; RUN: opt -disable-output -debug-pass-manager %s 2>&1 \
Index: test/Other/new-pass-manager.ll
===================================================================
--- test/Other/new-pass-manager.ll
+++ test/Other/new-pass-manager.ll
@@ -355,13 +355,11 @@
 ; CHECK-AA-MODULE-INVALIDATE: Running analysis: AAManager
 ; CHECK-AA-MODULE-INVALIDATE: Finished llvm::Function pass manager run
 ; CHECK-AA-MODULE-INVALIDATE: Running pass: InvalidateAnalysisPass
-; CHECK-AA-MODULE-INVALIDATE: Invalidating analysis: AAManager
 ; CHECK-AA-MODULE-INVALIDATE: Invalidating analysis: GlobalsAA
 ; CHECK-AA-MODULE-INVALIDATE: Running pass: RequireAnalysisPass
 ; CHECK-AA-MODULE-INVALIDATE: Running analysis: GlobalsAA
 ; CHECK-AA-MODULE-INVALIDATE: Starting llvm::Function pass manager run
 ; CHECK-AA-MODULE-INVALIDATE: Running pass: AAEvaluator
-; CHECK-AA-MODULE-INVALIDATE: Running analysis: AAManager
 ; CHECK-AA-MODULE-INVALIDATE: Finished llvm::Function pass manager run
 ; CHECK-AA-MODULE-INVALIDATE: Finished llvm::Module pass manager run
 
Index: unittests/Transforms/Scalar/LoopPassManagerTest.cpp
===================================================================
--- unittests/Transforms/Scalar/LoopPassManagerTest.cpp
+++ unittests/Transforms/Scalar/LoopPassManagerTest.cpp
@@ -572,7 +572,6 @@
   // invalidation and running.
   EXPECT_CALL(MFPHandle, run(HasName("f"), _))
       .WillOnce(Return(getLoopPassPreservedAnalyses()));
-  EXPECT_CALL(MLAHandle, invalidate(_, _, _)).Times(3);
   EXPECT_CALL(MLAHandle, run(HasName("loop.0.0"), _, _));
   EXPECT_CALL(MLAHandle, run(HasName("loop.0.1"), _, _));
   EXPECT_CALL(MLAHandle, run(HasName("loop.0"), _, _));