[NPM][NFC] Chain PreservedAnalyses methods (#129505)

Author: optimisan

llvm/include/llvm/IR/Analysis.h

@@ -128,30 +128,36 @@ class PreservedAnalyses {
   }
 
   /// Mark an analysis as preserved.
-  template <typename AnalysisT> void preserve() { preserve(AnalysisT::ID()); }
+  template <typename AnalysisT> PreservedAnalyses &preserve() {
+    preserve(AnalysisT::ID());
+    return *this;
+  }
 
   /// Given an analysis's ID, mark the analysis as preserved, adding it
   /// to the set.
-  void preserve(AnalysisKey *ID) {
+  PreservedAnalyses &preserve(AnalysisKey *ID) {
     // Clear this ID from the explicit not-preserved set if present.
     NotPreservedAnalysisIDs.erase(ID);
 
     // If we're not already preserving all analyses (other than those in
     // NotPreservedAnalysisIDs).
     if (!areAllPreserved())
       PreservedIDs.insert(ID);
+    return *this;
   }
 
   /// Mark an analysis set as preserved.
-  template <typename AnalysisSetT> void preserveSet() {
+  template <typename AnalysisSetT> PreservedAnalyses &preserveSet() {
     preserveSet(AnalysisSetT::ID());
+    return *this;
   }
 
   /// Mark an analysis set as preserved using its ID.
-  void preserveSet(AnalysisSetKey *ID) {
+  PreservedAnalyses &preserveSet(AnalysisSetKey *ID) {
     // If we're not already in the saturated 'all' state, add this set.
     if (!areAllPreserved())
       PreservedIDs.insert(ID);
+    return *this;
   }
 
   /// Mark an analysis as abandoned.
@@ -161,7 +167,10 @@ class PreservedAnalyses {
   ///
   /// Note that you can only abandon a specific analysis, not a *set* of
   /// analyses.
-  template <typename AnalysisT> void abandon() { abandon(AnalysisT::ID()); }
+  template <typename AnalysisT> PreservedAnalyses &abandon() {
+    abandon(AnalysisT::ID());
+    return *this;
+  }
 
   /// Mark an analysis as abandoned using its ID.
   ///
@@ -170,9 +179,10 @@ class PreservedAnalyses {
   ///
   /// Note that you can only abandon a specific analysis, not a *set* of
   /// analyses.
-  void abandon(AnalysisKey *ID) {
+  PreservedAnalyses &abandon(AnalysisKey *ID) {
     PreservedIDs.erase(ID);
     NotPreservedAnalysisIDs.insert(ID);
+    return *this;
   }
 
   /// Intersect this set with another in place.

llvm/lib/CodeGen/MachineScheduler.cpp

@@ -602,11 +602,10 @@ MachineSchedulerPass::run(MachineFunction &MF,
   if (!Changed)
     return PreservedAnalyses::all();
 
-  PreservedAnalyses PA = getMachineFunctionPassPreservedAnalyses();
-  PA.preserveSet<CFGAnalyses>();
-  PA.preserve<SlotIndexesAnalysis>();
-  PA.preserve<LiveIntervalsAnalysis>();
-  return PA;
+  return getMachineFunctionPassPreservedAnalyses()
+      .preserveSet<CFGAnalyses>()
+      .preserve<SlotIndexesAnalysis>()
+      .preserve<LiveIntervalsAnalysis>();
 }
 
 bool PostMachineSchedulerLegacy::runOnMachineFunction(MachineFunction &MF) {