[CodeGen][NPM] VirtRegRewriter: Set VirtReg flag

Author: optimisan

llvm/include/llvm/CodeGen/VirtRegMap.h

@@ -248,6 +248,14 @@ class VirtRegRewriterPass : public PassInfoMixin<VirtRegRewriterPass> {
   static bool isRequired() { return true; }
 
   void printPipeline(raw_ostream &OS, function_ref<StringRef(StringRef)>) const;
+
+  MachineFunctionProperties getSetProperties() const {
+    if (ClearVirtRegs) {
+      return MachineFunctionProperties().set(
+          MachineFunctionProperties::Property::NoVRegs);
+    }
+    return {};
+  }
 };
 
 } // end llvm namespace

llvm/lib/CodeGen/VirtRegMap.cpp

@@ -302,6 +302,8 @@ bool VirtRegRewriterLegacy::runOnMachineFunction(MachineFunction &MF) {
 PreservedAnalyses
 VirtRegRewriterPass::run(MachineFunction &MF,
                          MachineFunctionAnalysisManager &MFAM) {
+  MFPropsModifier _(*this, MF);
+
   VirtRegMap &VRM = MFAM.getResult<VirtRegMapAnalysis>(MF);
   LiveIntervals &LIS = MFAM.getResult<LiveIntervalsAnalysis>(MF);
   LiveRegMatrix &LRM = MFAM.getResult<LiveRegMatrixAnalysis>(MF);