add a new method

Author: optimisan

llvm/include/llvm/IR/PassManager.h

@@ -491,6 +491,22 @@ template <typename IRUnitT, typename... ExtraArgTs> class AnalysisManager {
   /// invalidate them, unless they are preserved by the PreservedAnalyses set.
   void invalidate(IRUnitT &IR, const PreservedAnalyses &PA);
 
+  /// Directly clear a cached analysis for an IR unit.
+  ///
+  /// Using invalidate() over this is preferred unless you are really
+  /// sure you want to *only* clear this analysis without asking if it is
+  /// invalid.
+  template <typename AnalysisT> void clearAnalysis(IRUnitT &IR) {
+    AnalysisResultListT &ResultsList = AnalysisResultLists[&IR];
+    AnalysisKey *ID = AnalysisT::ID();
+
+    auto I =
+        llvm::find_if(ResultsList, [&ID](auto &E) { return E.first == ID; });
+    assert(I != ResultsList.end() && "Analysis must be available");
+    ResultsList.erase(I);
+    AnalysisResults.erase({ID, &IR});
+  }
+
 private:
   /// Look up a registered analysis pass.
   PassConceptT &lookUpPass(AnalysisKey *ID) {

llvm/lib/CodeGen/MachineFunctionAnalysis.cpp

@@ -48,6 +48,6 @@ MachineFunctionAnalysis::run(Function &F, FunctionAnalysisManager &FAM) {
 
 PreservedAnalyses FreeAllAnalysesPass::run(Function &F,
                                            FunctionAnalysisManager &FAM) {
-  FAM.clear(F, F.getName());
+  FAM.clearAnalysis<MachineFunctionAnalysis>(F);
   return PreservedAnalyses::all();
 }