Index: include/llvm/Analysis/ProfileSummaryInfo.h
===================================================================
--- include/llvm/Analysis/ProfileSummaryInfo.h
+++ include/llvm/Analysis/ProfileSummaryInfo.h
@@ -40,7 +40,7 @@
 // units. This would require making this depend on BFI.
 class ProfileSummaryInfo {
 private:
-  Module &M;
+  Module *M;
   std::unique_ptr<ProfileSummary> Summary;
   void computeSummary();
   void computeThresholds();
@@ -48,7 +48,7 @@
   Optional<uint64_t> HotCountThreshold, ColdCountThreshold;
 
 public:
-  ProfileSummaryInfo(Module &M) : M(M) {}
+  ProfileSummaryInfo(Module *M) : M(M) {}
   ProfileSummaryInfo(ProfileSummaryInfo &&Arg)
       : M(Arg.M), Summary(std::move(Arg.Summary)) {}
   /// \brief Returns true if \p F is a hot function.
@@ -59,6 +59,8 @@
   bool isHotCount(uint64_t C);
   /// \brief Returns true if count \p C is considered cold.
   bool isColdCount(uint64_t C);
+  /// \brief Checks if \p newM is up-to-date, if not, invalidate Summary.
+  void resetModule(Module *NewM);
 };
 
 /// An analysis pass based on legacy pass manager to deliver ProfileSummaryInfo.
Index: lib/Analysis/ProfileSummaryInfo.cpp
===================================================================
--- lib/Analysis/ProfileSummaryInfo.cpp
+++ lib/Analysis/ProfileSummaryInfo.cpp
@@ -57,7 +57,7 @@
 void ProfileSummaryInfo::computeSummary() {
   if (Summary)
     return;
-  auto *SummaryMD = M.getProfileSummary();
+  auto *SummaryMD = M->getProfileSummary();
   if (!SummaryMD)
     return;
   Summary.reset(ProfileSummary::getFromMD(SummaryMD));
@@ -113,6 +113,13 @@
       getMinCountForPercentile(DetailedSummary, ProfileSummaryCutoffCold);
 }
 
+void ProfileSummaryInfo::resetModule(Module *newM) {
+  if (newM == M)
+    return;
+  M = newM;
+  Summary.reset(nullptr);
+}
+
 bool ProfileSummaryInfo::isHotCount(uint64_t C) {
   if (!HotCountThreshold)
     computeThresholds();
@@ -127,7 +134,9 @@
 
 ProfileSummaryInfo *ProfileSummaryInfoWrapperPass::getPSI(Module &M) {
   if (!PSI)
-    PSI.reset(new ProfileSummaryInfo(M));
+    PSI.reset(new ProfileSummaryInfo(&M));
+  else
+    PSI->resetM(&M);
   return PSI.get();
 }
 
@@ -142,7 +151,7 @@
 char ProfileSummaryAnalysis::PassID;
 ProfileSummaryInfo ProfileSummaryAnalysis::run(Module &M,
                                                ModuleAnalysisManager &) {
-  return ProfileSummaryInfo(M);
+  return ProfileSummaryInfo(&M);
 }
 
 // FIXME: This only tests isHotFunction and isColdFunction and not the